Dissertations / Theses on the topic 'Ichthyoplankton'

Understanding the early life stages of fishes and the processes influencing their survival has been at the heart of the fisheries oceanography since the beginning of the 20th century. By focusing on spatial and temporal patterns in the ichthyoplankton (those early stages whose horizontal location is largely determined by currents), it is possible to gain some understanding of interrelationships among environmental conditions, fish spawning phase and dispersal/survival dynamics of the planktonic stages of fish. The different physical and/or biological processes controlling Larval Fish Assemblages (LFAs) variability (abundances, composition and distribution) act at very different space and time scales. Sampling the sea at the appropriate frequency and at adequate time and space scales is required to evaluate those mechanisms. These studies are insufficiently developed in the Balearic Archipelago, a hotspot for biodiversity located in an extremely dynamic area of the Mediterranean. With this premise in mind, the main objective of the thesis was to deepen in the knowledge of LFA dynamics in the Balearic Sea (NW Mediterranean) at different spatio-temporal scales. Four different approaches were addressed. At a sub-seasonal temporal scale, the influence of coastal environmental conditions during the shift from winter-spring to summer on fish larvae assemblages in a temperate area was evaluated. Larval fish assemblages were sampled fortnightly at three stations located in coastal waters off southern Mallorca from March to August 2007, covering the main spawning period for the resident coastal fish in this region. The larval fish assemblage showed clear seasonality with higher specific abundance but lower diversity in the spring, probably linked to a spatial (at the vertical scale) shift in the energy flow, which may trigger the summer spawning of many bottom-dwelling species. At the submesoscale domain, the factors that may regulate the previously suggested high levels of larval self-recruitment were explored in Cabrera National Park (CNP), an insular Marine Protected Area (MPA) located off southern Mallorca. Our study attributes the regulation of larval arrival to the MPA to a combination of retention by topographically generated circulation patterns around the island and shelf break frontal dynamics. Also at scales smaller than the mesoscale, we examined fish larval distribution drivers in Palma Bay, a large (~20 Km) wind-driven microtidal bay in the southern coast of Mallorca. Distributions and abundances of fish larvae in the Bay were analyzed and interpreted in the context of the observed circulation patterns, adult habitat distribution and spawning traits. Acoustic Doppler Current Profiler (ADCP) observations showed the presence of retentive flow patterns in the middle of the Bay enhancing local larval accumulation and self-recruitment. A multivariate approach based on Redundancy Analysis (RDA) revealed differences between the larval fish assemblages in the Bay, constituted by small pelagic and benthopelagic families (Gobiidae, Chromis chromis and Serranus hepatus) and offshore larvae, mostly from meso and large pelagic fish. These larval fish assemblages were structured according to depth variations and zooplankton abundance, and remained relatively unmixed because of the circulation patterns in the mouth of the Bay that uncouple its dynamics from alongshelf circulation. At mesoscale level, we investigated the effect of two hydrographic scenarios, representing well-known contrasting examples of the early summer mesoscale dynamics in the archipelago, on the summer larval fish assemblages during two cruises in 2004 and 2005. While depth was the most important variable in explaining the assemblage structure and diversity observed under both scenarios, indicators of mesoscale activity (dynamic height, geostrophic velocity) contributed significantly to understanding the dynamics of the larval fish community. The larval assemblage dynamics are discussed in terms of species-specific and extrinsic factors, including future consequences of potential changes in these environmental scenarios. The main results of this thesis are put together in context in a general discussion section and shortcomings and future directions are explored.
Desde principios del siglo veinte, el estudio de los estadios tempranos de los peces y de los procesos que influyen en su supervivencia forma parte de la oceanografía pesquera. La investigación de los patrones temporales y espaciales del ictiopláncton hace posible entender las relaciones entre las condiciones del ambiente, la fase reproductiva de los adultos y la dinámica de supervivencia y retención de los estadios planctónicos de los peces. Los diferentes procesos físicos y/o biológicos que controlan la variabilidad (abundancia, composición y distribución) en las comunidades de larvas de peces (a partir de aquí LFA, del inglés Larval Fish Assemblage) actúan a escalas espaciales y temporales muy diferentes. Se hace necesario por tanto muestrear en el mar con la frecuencia apropiada y a la escala espacio-temporal adecuada para evaluar esos mecanismos. Este tipo de estudios son escasos en el archipiélago Balear, punto de interés de la biodiversidad y situado en un área del Mediterráneo extremadamente dinámica. Teniendo todo lo anterior en cuenta, el principal objetivo de la tesis fue profundizar en el conocimiento de la dinámica de las LFA en el Mar Balear, a diferentes escalas espacio-temporales. Se realizaron cuatro aproximaciones diferentes. A escala temporal, se evaluó la influencia de las condiciones ambientales costeras durante la transición primavera temprana-verano sobre las LFAs. Se realizaron muestreos quincenales entre marzo y agosto (cubriendo el pico de puesta de la mayoría de las especies de la zona) en tres estaciones de la zona costera del sur de Mallorca. Las LFAs reflejaron claramente la estacionalidad de la zona con una alta abundancia de especies pero bajas densidades de larvas en primavera, probablemente relacionada con la transición espacial (en el plano vertical) del flujo de energía que seguramente desencadena la puesta estival de muchas de las especies cercanas al fondo. A una escala menor que mesoescala, se estudiaron los factores que regulan los altos niveles de auto reclutamiento previamente sugeridos para el Parque Nacional de Cabrera. Nuestro estudio atribuye la regulación de la llegada de larvas al área a una combinación de retención por los patrones de circulación generados por la topografía alrededor de Mallorca y la dinámica asociada a un frente de plataforma. También a escala inferior a la mesoescala, examinamos los agentes responsables de la distribución de LFAs en la bahía de Palma en la costa sur de Mallorca. Se analizaron e interpretaron la abundancia y distribución horizontal de las larvas de peces en la bahía en el contexto de los patrones de circulación observados, el hábitat de los adultos y las estrategias de puesta. Mediante observaciones de un perfilador de corrientes mediante Doppler, se describió la presencia de patrones retentivos de circulación en el medio de la bahía que favorecen la acumulación de larvas locales y el auto reclutamiento. Una aproximación multivariante basada en el análisis de redundancia (RDA) reveló diferencias entre la comunidad de la bahía formada por familias bentopelágicas y de pequeños pelágicos y una LFA de especies más lejanas a la costa, principalmente mesopelágicos y grandes pelágicos. Esas comunidades estaban estructuradas según variaciones en profundidad de abundancia de zooplancton y permanecían relativamente separadas debido a que los patrones de circulación a la entrada de la bahía separan su dinámica interna de la circulación en la plataforma. A nivel de mesoescala investigamos mediante dos campañas en años consecutivos el efecto que ejercen dos escenarios hidrográficos (que representan ejemplos de escenarios muy contrastados entre sí característicos de la dinámica de mesosescala en verano en el archipiélago) sobre las LFAs estivales en la zona. Bajo ambos escenarios, la profundidad resultó ser la variable que mejor explicaba la estructura de la comunidad y su diversidad. Aun así, los indicadores de actividad mesoescalar (altura dinámica, velocidad geostrófica) contribuyeron de manera significativa a entender la dinámica de las LFAs. Los principales resultados de esta tesis se tratan como conjunto en una discusión general final donde también se comentan las limitaciones y se exploran las posibilidades de futuro.
Des de principis del segle vint, l’estudi dels estadis primerencs dels peixos i dels processos que influeixen en la seva supervivència forma part de l’oceanografia pesquera. La recerca dels patrons temporals i espacials del ictioplàncton fa possible entendre les relacions entre les condicions de l’ambient, la fase reproductiva dels adults i la dinàmica de supervivència i retenció dels estadis planctònics dels peixos. Els diferents processos físics i biològics que controlen la variabilitat (abundància, composició i distribució) en les comunitats de larves de peixos (d’aquí endavant LFA, de l’anglès larval Fish Assemblage) actuen a escales espacials i temporals molt diferents. Es fa necessari per tant mostrejar la mar amb la freqüència adient i a la escala espaitemporal adequada per avaluar aquests mecanismes. Aquest tipus d’estudi son escassos a les Illes Balears, punt d’interès de la biodiversitat i situades a un àrea de la Mediterrània extremadament dinàmica. Amb tot lo anterior en ment, l’objectiu principal d’aquesta tesi va ser augmentar el coneixement de la dinàmica de les LFA a la Mar Balear, a diferents escales espai-temporals. Es varen realitzar quatre aproximacions diferents. A l’escala temporal, es va avaluar la influencia de les condicions ambientals costaneres durant la transició primavera-estiu sobre les LFAs. Es varen realitzar mostreigs quinzenals de març a agost (pic de posta de la majoria de les especies de la zona) a tres estacions costaneres del sud de Mallorca. Les LFAs varen reflectir clarament la estacionalitat de la zona amb una alta abundància d’espècies però amb baixes densitats de larves a la primavera amb molta probabilitat relacionada amb la transició espacial (dins del pla vertical) del flux d’energia que segurament desencadena la posta estival de moltes especies properes al fons. A una escala menor que la mesoescala, es varen estudiar els factors que regulen els alts nivells de auto reclutament prèviament suggerits per el Parc Nacional de Cabrera. El nostre estudi atribueix la regulació de l’arribada de larves al àrea a una combinació de retenció pels patrons de circulació generats per la topografia al voltant de Mallorca i la dinàmica associada a un front de plataforma. També a escala inferior a mesoescala, vàrem examinar els agents responsables de la distribució del LFA a la badia de Palma a la costa sud de Mallorca. Es varen analitzar i interpretar la abundància i distribució horitzontal de les larves de peixos a la badia en el context dels patrons de circulació observats, l’habitat dels adults i les estratègies de posta. Mitjançant observacions amb un perfilador de corrents Doppler es va descriure la presencia de patrons retentius de circulació al mig de la badia que afavoreixen la acumulació de larves locals i el auto reclutament. Una aproximació multivariant basada en l’anàlisi de redundàncies (RDA) va revelar diferencies entre la comunitat de la badia formada per famílies bentopelàgiques i de petits pelàgics i una LFA d’espècies mes allunyades de costa, principalment mesopelàgics i grans pelàgics. Aquestes comunitats estaven estructurades segons variacions en profunditat de abundància de zooplàncton i romanien relativament separades degut a que els patrons de circulació a l’entrada de la badia separen la seva dinàmica interna de la circulació a la plataforma. A nivell de mesoescala vàrem investigar mitjançant dues campanyes a anys consecutius l’efecte que exerceixen dos escenaris hidrogràfics (que representen exemples d’escenaris molt contrastats l’un de l’altre característics de la dinàmica de mesoscale a l’estiu a l’arxipèlag) sobre les LFAs estiuenques a la zona. Sota ambdós escenaris, la fondària va resultar ésser la variable que millor explicava l’estructura de la comunitat i la seva diversitat. Tot i això, els indicadors d’activitat mesoscalar (alçada dinàmica i velocitat geostrofica) varen contribuir se manera significativa a entendre la dinàmica de les LFAs. Els principals resultat d’aquesta tesi es tracten com a conjunt a una discussió general final on també es comenten les limitacions i s’exploren les possibilitats de futur.

Ichthyoplankton dynamics in the permanently open Kowie Estuary, in the warm temperate region of South Africa was investigated. The composition, abundance, distribution and seasonality of larval fishes were studied over a two year period between 2004 and 2006. Additionally, tidal exchange of ichthyoplankton and the use of frontal zones in the mouth region of the estuary were also explored between 2008 and 2009. Temporal and spatial trends in occurrence of larval fishes within the estuary and associated marina were obtained from data collected seasonally using boat-based plankton netting at 14 sampling stations along the length of the estuary. A total of 11 128 larval fishes were collected, representing 23 families and 38 taxa. Clupeidae and Gobiidae were the dominant fish families, contributing 47.0 % and 24.7 % respectively to the total catch. Estuarine resident species dominated the overall catch (91 %). A notable absence of older stage larvae and early juveniles characterised the artificial channels of the marina and estuary mouth region. This was attributed to the absence of a shallow, marginal water habitat typical of successful estuarine nursery areas. Tidal exchange of larval fishes was investigated in the Kowie Estuary using a new technique. A set of drifting light traps were set repetitively on the ebb and flood tide every second night for two consecutive 14 day periods during the peak estuarine recruitment period. A total of 553 larval fishes were caught during the study, representing nine families and 26 species. Blenniidae and Clupeidae dominated the catches. Family and species occurrence changed with tide state. Species richness (d) and diversity (H’) varied with tide and was highest on flood tides. Estuary-dependent species, such as Omobranchus woodii were more dominant on flood tides, whilst larvae of marine-spawned species, such as Sardinops sagax, were dominant on the ebb tide. Light trap catches yielded a different composition in terms of development stage / size and species, when compared to towed net studies. Towed plankton nets were again used to study the shear fronts that characterise the mouth region of the canalised Kowie Estuary. It was hypothesised that the convergence zone of the front provides feeding opportunities for ichthyoplankton. Ichthyoplankton, zooplankton and phytoplankton was collected from within and immediately outside of the convergence zone during frontal conditions. Species specific distribution trends emerged from this study. Postflexion larvae and early juvenile stages of the estuary dependent Mugilidae were only present in the foam line of the convergence zones. Some known predators of ichthyoplankton were also present in slightly higher numbers in the convergence zone (isopods) while other predators such as mysid shrimps, chaetognaths and cnidarians were more abundant out of the convergence zone. It appears that these zones may provide access to temporary food patches in the lower estuary but will be accompanied by a trade-off with increased isopod predators. The Kowie Estuary is a heavily impacted system and lack of adequate freshwater supply; artificial channelling and pollution ultimately have a negative impact of the success of this system as a nursery area. Rehabilitation of marginal areas in the lower estuary and marina is suggested as remedial action to re-establish the integrity of the nursery function this system could offer.

Many lotic fish species use natural patterns of variation in discharge and water temperature as spawning cues and these natural patterns are often altered by river regulation. The effects of spring discharge and water temperature variation on the spawning of shovelnose sturgeon Scaphirhynchus platorynchus and other fishes in the upper Missouri River have not been well documented. In 2006, 2007, and 2008, I had the unique opportunity to study the effects of experimental discharge levels on ichthyoplankton density in the lower Marias River, a regulated tributary to the upper Missouri River. The objective of this study was to evaluate the effects of contrasting discharge treatments and water temperature variation on spatial and temporal variation in spawning of shovelnose sturgeon (and other species sampled as bycatch) as measured by embryonic and larval fish density in the lower Marias River. Ichthyoplankton was sampled about every four days in June and July of 2006, 2007, and 2008. Overall larval fish density was greater in 2006 than in 2007, and increased density was associated with increased discharge in 2006. In 2006, shovelnose sturgeon spawning occurred in the Marias River in conjunction with the ascending, peak (134 m 3/s), and descending portions of the spring hydrograph and water temperatures from 16 oC to 19 oC. No evidence of sturgeon spawning was documented in the lower Marias River in 2007 when peak discharge remained low (9 m 3/s to 14 m 3/s) despite the occurrence of water temperatures suitable for shovelnose sturgeon embryo development. In 2008, shovelnose sturgeon spawning occurred in conjunction with the peak (118 m 3/s) and descending portions of the spring hydrograph, and during a prolonged period of increased discharge (28 m 3/s to 39 m 3/s), coupled with water temperatures from 11 oC to 23 oC in the lower Marias River. These data suggest that discharge must reach a threshold level (28 m 3/s), and should be coupled with water temperatures suitable (12 oC to 24 oC) or optimal (16 oC to 20 oC) for shovelnose sturgeon embryo development, to provide a spawning cue to shovelnose sturgeon in the lower Marias River.

The objective of this dissertation was to examine sailfish (Istiophorus platypterus) and blue marlin (Makaira nigricans) spawning in the Straits of Florida, with a specific focus on 1) the physical and biological characteristics of the spawning environment, and 2) the role of the region within the broader spawning patterns of these two species. In order to accomplish these objectives, two years of monthly ichthyoplankton collections and physical measurements across the Straits of Florida were combined with a finer-scale Lagrangian study. Additionally, a molecular species-identification methodology was developed that was both high-throughput and suitable for use with a broad taxonomic range of species. An initial analysis considered the diversity, assemblages and associated habitat of the larvae of large and medium size pelagic species. In total 36 species and 14,295 individuals were collected during this study, with the highest diversity occurring during the summer, and in the western frontal region of the Florida Current. Sailfish were included in an assemblage with Auxis rochei, A. thazard and Euthynnus alleterattus, all species found in highest abundance during the summer along the western edge of the Straits of Florida. Blue marlin grouped most closely with Thunnus atlanticus, Ruvettus pretiosus and Lampris guttatus, all summer spawners, whose larvae tended to occur further offshore. The primary environmental factors associated with these assemblages were SST (highest summer-early fall), day-length (highest early summer), thermocline depth (shallowest on the Florida side) and fluorescence (highest on the Florida side). A Lagrangian sampling effort was then used to more specifically evaluate the role of frontal zones in sailfish spawning. The results of this sampling indicated that the highest levels of sailfish spawning occurred in a frontal zone associated with the formation of a submesoscale frontal eddy. This spawning resulted in the first-feeding larvae occupying an area rich in prey items. Given the small spatial-scale of the front, and the distribution of the eggs of adult prey items, the results of this work would suggest that sailfish are actively targeting features for spawning that are favorable to the growth and survival of their larvae. Finally the relative importance of the Straits of Florida as a spawning ground was evaluated by calculating the annual egg production of both sailfish and blue marlin within this region. In total it was estimated that 2.1% of western Atlantic sailfish spawning and 1.6% of Atlantic wide blue marlin spawning occurs in the SF. Pop-up satellite tags deployed on sailfish at the start of the spawning season revealed their short residency times in the SF, suggesting that a large (≈10%) transient portion of the sailfish population is responsible for the SF egg production. These results indicate that the SF is a migratory bottleneck for sailfish. In conclusion the results of this study indicate that a hierarchy of physical and biological processes influence the distribution of billfish spawning in space and time. The results provide insights into the movement patterns and life history strategies of these species, and ultimately may aid in the development of the spatially explicit ecosystem based management approaches that are currently being advocated.

Biophysical dispersal models (BDMs) — a hydrodynamic model coupled with a biological model — lend themselves to inferring potential connectivity patterns, as experimental studies using current methods are inherently difficult over extended spatial and temporal scales. This thesis explored the biological processes that affect the connectivity patterns of ichthyoplankton using four related data chapters. The first data chapter, a meta-analysis of connectivity studies using BDMs, investigated both trends and consequences of modelling choices on derived connectivity patterns. The results of this meta-analysis provide a useful framework on parameter choice for future consideration of connectivity studies. The second data chapter is an experiment measuring the ontogenetic vertical migration of reef fish off the coast of south-eastern Australia. The ichthyoplankton sampled demonstrated deeper migration with both increasing ontogenetic stage and length. The third data chapter is a theoretical modelling chapter that investigated the effect of different swimming and migration behaviours and differences in the parameterisation and implementation of vertical migration in a BDM. The fourth data chapter synthesised the results from the previous three data chapters and explored the predicted connectivity patterns of an endemic and threatened Australian reef fish, the black cod (Epinephelus daemelii) using a BDM. E. daemelii larvae showed strong connections to both the natal and proximate regions. Within the context of the current marine protected area (MPA) network of NSW, strong settlement regions had only moderate or no no-take areas. The results of this thesis increase our understanding of the influence of behaviour on the dispersal patterns of marine larvae along the east Australian coast.

Thesis (M.S.) -- University of Maryland, College Park, 2004.
Thesis research directed by: Marine, Estuarine, Environmental Sciences Graduate Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

On April 20th, 2010, a fire broke out on the Deepwater Horizon (DWH) offshore oil drilling rig on the Macondo prospect located off the coast of the Gulf of Mexico (GOM). This fire and resulting explosions resulted in the sinking of the Deepwater Horizon rig and the largest marine oil spill in history. An estimated 4.9 million (+/- 10%) barrels were released into the Gulf of Mexico over the ensuing 87 days. Many economically important fish species spawn in northern Gulf of Mexico waters; the spawning seasons and pelagic larval phase of many of these species occur within the temporal extent of the DWH oil spill (April through July). Fish eggs and larvae in waters exposed to Macondo oil likely experienced lethal and sublethal physiological effects, leading to potential losses in year class strength depending on the proportion of a population’s larval production encountering oil. Differing spatial distributions of larvae due to different spawning locations and seasons could predict that some species were disproportionately affected by the DWH oil spill. This study aims at quantifying the impact of the spill across numerous taxa, by estimating the proportion of species-, genus-, or family-specific fish larval abundances located within the spatial/temporal domain of the DWH spill until the Macondo well was capped. Estimates and related uncertainties were based on empirical ichthyoplankton data collected over 27 years and on observed and modeled distribution of surface oil slicks and concentrations. In addition, two hypothetical oil spills were simulated on the Western Florida Slope and on the Western interior of the Gulf of Mexico to assess the impact of oil spills to the ichthyoplankton from different offshore locations that would have occurred during the DWH spill period. Ichthyoplankton data collected during annual plankton surveys (and other resource surveys) as part of the Southeast Area Monitoring and Assessment Program – Gulf of Mexico (SEAMAP) during years 1982-2009 were used to describe the composition and distribution of ichthyoplankton in the northern Gulf of Mexico. The SEAMAP larval fish data along with oil surface distributions (both actual and simulated) were used to estimate the proportions of larvae of 115 selected fish taxa that were potentially exposed to DWH oil. Bootstrapping methods were applied to the SEAMAP data to quantify the variability. Proportions of larval fish potentially exposed to oil were calculated for four oil spill scenarios: (1) the DWH spill, (2) an September-December oil spill with the same spatial footprint as the DWH spill but occurring later in the year, (3) a west Florida Slope spill occurring during the months of April-July and centered at 27˚N, 85˚W, and (4) a western GOM spill occurring during the spring and centered at 27˚N, 93.5˚W. Spill scenarios (3) and (4) were modeled using the Connectivity Modeling System (CMS). The CMS is a Lagrangian model which predicts oil droplet distribution and degradation based on oil properties and ocean currents. Significant differences in the proportion of larvae potentially exposed were found in the DWH spill and the three simulations. The proportion of fish larvae exposed to the DWH spill varied between 0% (many species) and 26.8% (Cynoscion nebulosus). The proportion of fish larvae exposed to simulated spills varied between 0% and 78.9% (Bonapartia pedaliota in Western GOM spill). Both the west Florida Slope oil spill and the western GOM spills had a disproportionally greater impact on a larger number of taxa than the DWH spill, even after correcting for their larger spatial extent. For the DWH spill (Scenario 1), the potentially most impacted taxa were Cynoscion nebulosus, Engraulidae, Rachycentron canadum, and Etropus spp. If the DWH spill had occurred in the fall (Scenario 2), the most potentially impacted taxa would have been Leiostomus xanthurus, Elopidae, and Pomatomus saltatrix. For a west Florida slope exposure (Scenario 3), the potentially most impacted taxa would be Holocentridae, Acanthocybium solandri, Coryphaena spp., and Pomacanthidae. For a western GOM spill (Scenario 4), the most potentially impacted taxa would be Bonapartia pedaliota, Thunnus thynnus, Caranx spp., and Holocentridae.. The historical SEAMAP data set combined with the CMS modeling tool provides a powerful planning tool to understand the potential impacts of oil spills in the northern GOM and the relative sensitivity of locations in the Northern GOM to oil spill effects.

Fish larvae in Australian waters have been studied progressively in the last 2-3 decades including the distribution and abundance of taxa, growth and age, their prey and predators. However, the effect of nutrient limitation on ichthyoplankton is unstudied, particularly in the oligotrophic Australian waters. My study was aimed to examine the effect of natural or anthropogenic nutrients on the abundance, distribution, growth and condition of fish larvae along-shore of the NSW coast (latitude 30-34S), where the East Australian Current departs the NSW coast and generates local upwelling of cool nutrient-rich water. This study shows no significant difference in the total abundance or diversity of either larval fishes amongst the 112 taxa (111 families and 1 order), among regions within or upstream of the upwelling. However in both months, there were distinctive ichthyoplankton assemblages at the family level. The Carangidae, Labridae, Lutjanidae, Microcanthidae, Myctophidae and Scombridae were more abundant in the EAC or oceanic water masses, while the Callionymidae, Clupeidae, Platycephalidae, Sillaginidae and Terapontidae were mostly found in the surface or deep upwelled/uplifted water masses. This pattern is observed in other ichthyoplankton studies and may be a general and useful method to determine mixing of water masses. Larvae of silver trevally (Pseudocaranx dentex) and yellowtail scad (Trachurus novaezelandiae) were generally larger and less abundant in the topographically induced upwelling region, than north of the region in pre-upwelled conditions of the East Australian Current. Both species were mostly at the preflexion stage (less than 4.3 mm in body length and less than 10 days old) in the pre-upwelled conditions, particularly during November, and proportionally more larger and older larvae in the upwelled waters (mostly post-flexion, greater than 4.3 mm in body length and greater than 10 days old). Ages from sagittal otoliths ranged from 2-25 increments (~days) and exhibited linear growth for both species and months over the size range (3-15 mm standard length). The otolith radius-length relationship and the growth rates were similar between species and months, despite the 3-4C difference between months. Overall growth rates of the younger larvae were uniform throughout the entire sampling area (0.5-0.6 mm.d-1), while older larvae grew significantly faster in the upwelled water (0.41 mm.d-1) compared to the non-upwelled conditions (0.34 mm.d-1). Both species tended to be depleted in 13C in the upwelling region (from ???18.5 to ???19.0), consistent with expected ratios from deeper water, whereas the 15N composition tended to increase in Pseudocaranx, but decrease in Trachurus indicating different diets and possibly trophic level. The early life history of both species indicates spawning in pre-upwelled waters, but larval transport into upwelled waters is necessary for faster growth in the post-flexion stage. The assemblage of larval fishes did differ between the upwelled region and a region south of Sydney???s deepwater outfalls, but the difference was ascribed to a latitudinal effect and the EAC. Both larval carangids were enriched in 15N, possibly due to the enriched dissolved organic matter of primary treated sewage. In summary, this study found that the larval fish community can provide a biological means to trace water masses, and estimate their degree of mixing. Remarkably there was no significant effect of upwelling or sewage addition to the abundance or diversity of larval fish, in the nutrient poor waters of the East Australian Current. Larval carangids and pilchards were abundant in late spring off northern NSW, and their early life histories were inferred. Both larval carangid species seem to be spawned in the EAC waters, but as post-flexion larvae grew faster in the upwelled zone. Pre-flexion (less than 10 day old) larval carangids of both genera indicated spawning in the EAC, and the rarer post-flexion (greater than 10 days old) carangids grew faster in the upwelled waters. Here, both genera had stable isotope signatures characteristic of upwelled waters for carbon, but had different nitrogen signatures, indicative of different diets and trophic level status. Larval pilchards actually grew more slowly in the upwelling region, as observed in coastal waters off Japan, and their nursery grounds may be further offshore in the Tasman Front, analogous to their early life history in the Kuroshio Extension.

Larval fish assemblages were investigated during a three-year multidisciplinary project conducted off the coast of south-western Australia. Larvae were sampled using replicated oblique bongo net tows along a five-station transect extending from inshore (18m depth) to offshore waters (1000m depth). A total of 148 taxa from 93 teleost families were identified. Larvae of Gobiidae, and Blenniidae were abundant inshore, while larvae of pelagic and reef-dwelling families, such as Clupeidae, Engraulidae, Carangidae and Labridae were common in continental shelf waters. Larvae of oceanic families, particularly Myctophidae, Phosichthydae and Gonostomatidae, dominated offshore assemblages. Inshore larval fish assemblages were the most seasonal, in terms of species composition and abundance, with offshore assemblages the least so. Multivariate statistical analyses revealed larval fish assemblages to have a strong temporal and spatial structure. Assemblages were closely correlated to water masses, with species distributions reflecting both cross shelf and along-shore oceanographic processes and events. The strength and position of the warm, southward flowing Leeuwin Current, and of the cool, seasonal, northward flowing Capes Current were shown to drive much of the variability in the marine environment, and thus larval fish assemblages. Many of the distinctions between larval fish assemblages on the continental shelf were attributable to patterns of abundance in clupeiform larvae. While larvae of Engraulis australis and Spratelloides robustus showed clear seasonal and spatial distribution patterns, larvae of Sardinops sagax and Etrumeus teres were found throughout the year, with high interannual variability in abundance. Abundances of larvae from all pelagic clupeiform species were negatively correlated to microzooplankton concentrations. Peaks of abundance of S. sagax and E. teres, in particular, appeared to be better aligned with favourable transport and retention conditions. A detailed comparison of the horizontal and vertical distribution of larval fishes highlighted the influence of contrasting oceanographic conditions between summer and winter on larval fish assemblages. Although most fish larvae were found above the thermocline, depth distributions differed between taxa, and were shown to influence their offshore transport. Neustonic fish larvae showed potential for significant dispersion during summer, as a result of offshore Ekman transport. Mesoscale Leeuwin Current eddies were a feature of the oceanography of the region, and their influence on larval fish assemblages was examined in both an anti-cyclonic eddy (warm-core) and a cyclonic eddy (cold-core). The warm-core eddy contained larval fish assemblages that were distinct from those in the cold-core eddy, with lower larval fish concentrations, especially in the eddy centre. Although the eddies originated near the continental shelf, larval fish assemblages within both eddies were largely oceanic, probably a result of the age of the eddies when they were sampled (about 5 months). Overall, larval fish assemblages showed strong temporal and spatial structure, and were well aligned to water masses in the region. The unique oceanography off south western Australia thus has considerable implications for both larval fish transport, and potential recruitment to regional fisheries.

Estuaries are widely recognized as important habitats for the early life history stages of commercially and recreationally important marine fish species. In general the estuaries of northeast Florida are understudied, and there is a need to characterize the ichthyoplankton community at this important faunal boundary between temperate and tropical marine zones. To determine community structure and temporal patterns in the distribution and abundance of larval fish ingressing in to the Guana-Tolomato-Matanzas (GTM) estuary through its two inlets (St. Augustine and Matanzas), ichthyoplankton were sampled bi-weekly for one year at both inlets during nighttime spring flood tides beginning in March 2012. Samples were collected with a plankton net (1 m diameter with 1mm mesh) suspended 1 m below the surface in the water column. Over 30,000 individuals were collected, representing 74 taxa. Four families made up 90 % of the collection: Gobiidae (34.8 %), Sciaenidae (26.1 %), Engraulidae (19.3 %), and Gerreidae (9.3 %). Examination of the ichthyoplankton community revealed seasonal trends in species richness and in larval fish density; species richness and larval fish density were generally greatest during the protracted summer season. Spring and summer pulses in recruitment were evident in nearshore summer spawners (e.g., gobiids and engraulids), and winter peaks in recruitment were evident in marine spawned species (e.g., sciaenids, sparids, haemulids). The variety of taxa collected, and the patterns in the seasonal species assemblage of the ichthyoplankton community of the GTM estuary align with its geographical position near a faunal boundary.

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This present work was realized out in a profile of the coastal and marine zone of the continental shelf of Maranhão (MCS). This order to describe the existence of structure patterns of fish larvae species in the coastal and marine zone of the MCS, testing the hypothesis that the community structure is related to the environmental conditions of the region. The sampling was performed and distributed at seven collection points (MA1, MA2, MA3, MA4, MA5, MA6 and MA7), throughout nine campaigns in the months of April, August, October and November 2013; January, March, May, July and September 2014. The ichthyoplankton was obtained by horizontal trawls on the surface, using a conical – cylinder plankton net with mesh of 300 μm and 60 cm of mouth diameter. The variables “temperature”, “salinity”, “conductivity”, total dissolved solids – TDS, Water transparency, dissolved oxygen, suspended particulate matter, dissolved nutrients (phosphate and nitrite) were obtained on the water surface at all collection points. The canonical correspondence analysis (CCA) was used to verify the influence of environmental variables on larval abundance and distribution. During the sample period, 4.011 fish larvae were collected, belonging to 23 families, 40 genera and 31 species. The most abundant were Anchovilla lepidentostole, Cynoscion acoupa, Sardinella brasiliensis e Mugil sp. The diversity and richness of species occurred in a way that, at the point MA1 was strongly influenced by many individuals and few species with a high degree of dominance, while in the MA7 was recorded the greatest diversity and richness of species. The more parsimonious CCA model constructed by the forward selection considered the variables water transparency (M), SPM, salinity, TSD and conductivity sufficient to explain the abundance distributions of the species. All together, these variables accounted for 89.6% of the total abundance variation in the larval species. These analyzes demonstrated the existence of two distinct sets of species, namely: i) a set of coastal species with estuarine influence; Ii) a set of marine species with oceanic influence. In general, the formation of fish larvae in the coastal and marine environments of MCS was influenced by the environmental variables of this region. The formation of these sets showed that in the MCS there is a diverse ichthyofauna of commercial and ecological importance. This indicates this area as a zone in need of conservation, in which its characteristics must be preserved.
O presente trabalho foi realizado em um perfil da zona costeira e marinha da Plataforma Continental Maranhense (PCM). O objetivo foi descrever a existência de padrões da estrutura do conjunto de espécies das larvas de peixes na zona costeira e marinha da PCM, testando a hipótese de que a estrutura da comunidade está relacionada às condições ambientais da região. A amostragem foi distribuída entre 7 pontos de coletas (MA1, MA2, MA3, MA4, MA5, MA6 e MA7) durante nove campanhas. Os meses amostrados foram: abril, agosto, outubro e novembro de 2013 e janeiro, março, maio, julho e setembro de 2014. O ictioplâncton foi obtido através de arrastos horizontais na superfície usando rede de plâncton – cônico cilíndrico, com abertura de malha de 300 μm e 30 cm de boca. Os parâmetros temperatura, salinidade, profundidade de transparência, oxigênio dissolvido, material particulado em suspensão (MPS), sólidos totais dissolvidos, condutividade, TDS, pH, fosfato e nitrito foram obtidos na superfície da água em todos os pontos de coleta. Foram utilizadas as análises de correspondência canônica (CCA) para verificar a influência das variáveis ambientais sobre a abundância das larvas. Durante o período amostral foram coletadas 4.011 larvas de peixes, sendo identificadas 43 famílias e 31 espécies. As espécies mais abundantes foram Anchoviella lepidentostolle, Cynoscion acoupa e Mugil sp. A diversidade e riqueza de espécies ocorreram de maneira que, no ponto MA1 foi fortemente influenciado por muitos indivíduos e com poucas espécies com alto grau de dominância, enquanto que no MA7 foi registrada a maior diversidade e riqueza de espécies. O modelo de CCA mais parcimonioso construído pela seleção forward considerou as variáveis transparência da água (m), MPS, salinidade, TDS e condutividade suficientes para explicar as distribuições de abundância das espécies. Consideradas juntas, estas variáveis explicaram 89,6% da variação total das abundâncias no conjunto de espécies de larvas. Estas análises demonstraram a existência de dois conjuntos de espécies distintos, a saber: i) um conjunto de espécies costeiras com influência estuarina; ii) um conjunto de espécies marinhas com influência oceânica. Em geral, a formação da estrutura da comunidade das espécies de larvas de peixes nas zonas costeira e marinha da PCM foi influenciada por variáveis ambientais atuantes nesta área. A formação dos conjuntos das larvas de peixes mostrou que a PCM possui uma diversificada ictiofauna de importância comercial e ecológica. Isto indica esta área como zona de conservação, na qual suas características devem ser preservadas.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
This work was developed in the estuary of the Vaza-Barris River, Sergipe, Brazil, and established nine sampling stations in the hope to ensure maximum representation of the study area. In order to characterize the environment and community ichthyoplankton, we tried to recognize trends and distribution of these organisms to evaluate the role of the estuary as an environment conducive to growth in the early stages of local ichthyofauna. The campaigns were carried out every three months, from April 2010 to January 2011, on two consecutive days during the tide quadrature. For sampling it was used network-cylindrical conical type (500 μm), operated in the flow of ebb tide day and night, with two types of hauls in the surface and one meter deep. The parameters water temperature, dissolved oxygen, salinity, inorganic phosphate, chlorophyll "a", phaeophytin, nitrate and turbidity were obtained in surface of all sampling stations. We collected 38,781 eggs and 3,526 fish larvae. Eggs and larvae were present in all months and all sampling stations. We identified 42 different taxa, distributed in 21 families. The distribution and composition of ichthyoplankton in the estuary of the Vaza-Barris River were strongly influenced by environmental conditions, mainly by the penetration of marine waters through the tidal currents. Some families, like Engraulidae, Gobiidae (Bathygobius soporator, Ctenogobius spp., Gobionellus oceanicus, Gobiosoma nudum and Microgobius meeki), Sciaenidae (Bairdiella ronchus, Cynoscion leiarchus, Macrodon ancylodon, Micropogonias furnieri, Stellifer rastrifer and S. stellifer) and Achiridae (Achirus sp. and Trinectes sp.), occurred throughout the period studied in higher densities, while other rare, as Ostraciidae (Acanthostracion sp.) and Microdesmidae (Microdesmus longipinnis), were recorded for the first time in the region. The fact that families, which are economically and ecologically important, use the estuary during the development of its life cycle, emphasizes the importance of the area in the maintenance of estuarine fish species and the adjacent coastal zone.
O presente trabalho foi desenvolvido no estuário do rio Vaza-Barris, Sergipe, Brasil, sendo estabelecidas nove estações de amostragem na expectativa de garantir a máxima representatividade da área de estudo. Com o objetivo de caracterizar o ambiente e a comunidade ictioplanctônica, procurou-se reconhecer as tendências de distribuição desses organismos e avaliar o papel do estuário como ambiente propício ao desenvolvimento das fases iniciais da ictiofauna local. As campanhas foram realizadas a cada três meses, de abril de 2010 a janeiro de 2011, em dois dias consecutivos durante a maré de quadratura. Para a amostragem foi utilizada rede do tipo cônico-cilíndrica (500 μm), operada nos períodos vazante-diurno e vazante-noturno, em arrastos na superfície e a um metro de profundidade. Os parâmetros temperatura da água, oxigênio dissolvido, salinidade, fosfato inorgânico, clorofila “a”, feofitina, nitrato e turbidez foram obtidos na superfície de todas as estações de amostragem. Foram coletados 38.781 ovos e 3.526 larvas de peixes. Os ovos e as larvas estiveram presentes em todos os meses de amostragem e em todas as estações de coleta . Foram identificados 42 taxa distintos, distribuídos em 21 famílias. A distribuição e composição do ictioplâncton do estuário do rio Vaza-Barris foram fortemente influenciadas pelas condições ambientais, principalmente pela penetração de águas marinhas através das correntes de maré. Algumas famílias, como Engraulidae, Gobiidae (Bathygobius soporator, Ctenogobius spp., Gobionellus oceanicus, Gobiosoma nudum e Microgobius meeki), Sciaenidae (Bairdiella ronchus, Cynoscion leiarchus, Macrodon ancylodon, Micropogonias furnieri, Stellifer rastrifer e S. stellifer) e Achiridae (Achirus sp. e Trinectes sp.), ocorreram durante todo o período estudado em maiores densidades, enquanto outras raras, como Ostraciidae (Acanthostracion sp.) e Microdesmidae (Microdesmus longipinnis), foram registradas pela primeira vez na região. O fato de famílias econômica e ecologicamente importantes utilizarem o estuário durante o desenvolvimento do seu ciclo de vida, enfatiza a importância da área na manutenção da ictiofauna estuarina e da zona costeira adjacente.

Artificial reefs (ARs) have been deployed on the inner shelf of Paraná State, south Brazil, to recuperate marine biodiversity and as protection against destructive trawling activities. The purpose of this study was to offer a first characterization of the ichthyoplankton community associated with the ARs and the adjacent archipelago of Currais. Two sampling methodologies were used; 1) plankton net attached to an underwater scooter and; 2) light-traps. A hydrodynamic model was used to study dispersal trajectories to and from the study area. Sampling was conducted between 31.07.14 and 04.04.16. A total of 13 families and 11 species were identified, expanding the total species list of the study area with six species and four families; 63% of fish larvae caught on the ARs were of reef associated species; abundance and species richness was higher on the ARs compared to samples taken at a distance from the ARs. First occurrence of the invasive muzzled blenny Omobranchus punctatus was registered. The hydrodynamic model provided insight on dispersal trajectories and connectivity. The results of this study can be used to better define guidelines for sustainable use of the ARs and the Currais archipelago, a Marine National Park since 2013.
Recifes Artificiais (RA) foram implantados na plataforma interna do Paraná, sul do Brasil, para atuar como unidades anti-arrasto e para oferecer habitat e abrigo para a fauna local, na tentativa de recuperar a biodiversidade marinha ameaçada pelo pesca de arrasto. O principal objetivo deste estudo foi oferecer uma primeira caracterização da assembleia ictioplanctônica associada aos RAs e ao arquipélago de Currais. Coletas foram realizadas utilizando duas metodologias; 1) rede de plâncton acoplado a uma \"scooter\" subaquática e; 2) armadilhas de luz. Excursões amostrais foram realizadas entre 31.07.14 e 04.04.16. Um total de 13 famílias e 11 espécies de peixes representadas no ictioplâncton foram identificadas. Foi registrada a primeira ocorrência do blenídeo invasivo Omobranchus punctatus. A abundância de ictioplâncton foi maior em amostras dos RAs comparado às coletas em área-controle; 63% das larvas capturadas nos RAs foram de espécies recifais. Um modelo hidrodinâmico forneceu uma visão sobre as trajetórias de dispersão larval e conectividade ecológica na região. Os resultados deste estudo podem ser usados para melhor definir diretrizes para o uso sustentável dos RAs e do arquipélago de Currais, um Parque Nacional Marinho desde 2013.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In order to evaluate the Salminus brasiliensis larval diet in natural environment was analyzed the stomach contents of 200 individuals with standard length ranging between 7.00 to 13.99 millimeters. For that, the food items have been identified, classified and quantified by numeric frequency and occurrence. Were also obtained some morphometric data of both S. brasiliensis larvae and prey captured by them. For the larvae were assessed standard length and size of the mouth, while the prey has been evaluated the maximum height of the body. The material analyzed was collected in the Ilha Grande National Park region in a lotic remaining stretch of the Paraná River, in 18 stations distributed in the main channel, its tributaries and oxbow lakes. The diet of the larvae was predominantly composed of fish larvae, especially of Characiformes and Siluriformes. Cannibalism cases were reported demonstrating that this is a characteristic behavior of the species, and is independent on the availability of other food items. Dorado's larvae show a negative allometric relationship between the proportion size of the upper jaw relative to the standard length, it means, those variables do not grow proportionally throughout the growth. It was observed that there is no selectivity when taking into consideration the height of consumed prey, but their sizes remained within the maximum intake limit, and neither the heights of prey or even the height of the mouth were a factor limiting of intake.
Com o objetivo de avaliar a dieta de larvas de Salminus brasiliensis em ambiente natural, foi analisado o conteúdo estomacal de 200 de indivíduos com comprimento padrão variando entre 7.00 a 13.99 milímetros. Para tanto, os itens alimentares foram identificados e quantificados quanto à frequência numérica e de ocorrência. Foram obtidos alguns dados morfométricos tanto das larvas de S. brasiliensis como das presas ingeridas. Para as larvas foram avaliados o comprimento padrão e tamanho da boca, enquanto que das presas foi avaliado a altura máxima do corpo. O material analisado foi coletado na região do Parque Nacional de Ilha Grande em um trecho do remanescente lótico do rio Paraná, em 18 estações distribuídas na calha principal, seus tributários e lagoas marginais. A dieta das larvas foi composta predominantemente por larvas de peixes, principalmente de Characiformes e Siluriformes. Casos de canibalismo foram registrados demonstrando que este é um comportamento característico da espécie, e independe da disponibilidade de outros itens alimentares. As larvas do dourado apresentam uma relação alométrica negativa entre a proporção do tamanho da maxila superior e o comprimento padrão, isto é, essas variáveis não se desenvolvem proporcionalmente ao longo do crescimento. Pôde-se observar também que não há uma seletividade alimentar quando se leva em consideração a altura das presas consumidas, mas que seus tamanhos mantiveram-se dentro do limite máximo de ingestão, sendo que tanto as alturas das presas e quanto a abertura da boca foram um fator limitante na ingestão.

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CNPq
Este estudo teve como objetivo avaliar a distribuição espacial e temporal das assembleias do ictioplâncton do rio Cuiabá e áreas adjacentes, no período de novembro de 2007 a fevereiro de 2008, bem como estudar as relações de densidades dos ovos e larvas com os fatores locais físicos (temperatura, velocidade da água) químicos (fosfato, nitrogênio total, nitrogênio amoniacal), como indicadores da produtividade no ambiente, fatores bióticos (densidades de fitoplâncton e zooplâncton) e com os fatores regionais (nível do rio e pluviosidade), formando condições e locais favoráveis para seu desenvolvimento e sobrevivência nos estágios iniciais de vida dos peixes. As coletas do ictioplâncton foram realizadas em 14 pontos ao longo do rio e áreas adjacentes, com arrastos sub-superficiais de 20 e 40 cm de profundidade, com rede tipo cilindro-cônica de malha 300 μm. Concomitantemente, foram coletadas amostras de fitoplâncton e zooplâncton, bem como realizadas as medidas das variáveis locais e regionais. Após as coletas as amostras foram triadas e identificadas ao menor nível taxonômico possível. Para avaliar as diferenças nas densidades de ovos e larvas nos locais e nos meses de estudo, foi utilizado o teste de ANOVA por medidas repetidas. Foi utilizada uma correlação de Spearman para a análise das densidades de ovos e larvas com as variáveis regionais e com as variáveis locais. Para avaliar as densidades das larvas com as densidades do fitoplâncton e do zooplâncton também foi utilizada a correlação de Spearman, porém, este teste foi feito com as larvas que foram identificadas em nível de gênero e espécie, e posteriormente, com cada espécie de larva de peixe migrador. Para analisar a composição das estruturas das assembleias de larvas através das densidades nos locais foi utilizado o teste de Mantel parcial, entre as distâncias de similaridades, distâncias ambientais e geográficas. Para avaliar a diferença temporal entre os grupos de Characiformes e Siluriformes foi feito o teste de ANOVA por medidas repetidas. Foi realizada uma ordenação direta das densidades das larvas dos migradores nos pontos amostrais. Os resultados espaciais com as densidades de ovos (F1;10= 0,572; p=0,467), e larvas (F1;10= 3,494 ; p=0,091) não foram significativos. Os resultados temporais com as densidades de ovos (F3;30= 0,533; p=0,663) não foram significativos, já para as larvas (F3;30= 4,539; p=0,009) foram significativos, com picos de densidades em novembro e janeiro. Houve correlação significativa entre as densidades das larvas com o nitrogênio total (r=-0,127; p=0,025) e a temperatura da água (r=0,292; p=0,035). O teste de Mantel parcial mostrou que a variação ambiental não foi fator determinante na distribuição da composição taxonômica dos grupos ao longo do rio (r=-0,214; p=0,966) e que as assembleias de larvas apresentam significativa dependência geográfica (r=0,459; p=0,001), quanto mais próximos os pontos geograficamente, mais similares foram as composições taxonômicas. Os resultados taxonômicos mostraram diferença temporal significativa (F3;48= 3,994; p=0,012) entre os grupos dos Siluriformes e Characiformes.
The aim of this study is to assess the spatial and temporal distribution of Ichthyoplankton assemblies of the Cuiabá River and adjacent areas, from November 2007 to February 2008. We also studied the relationships of egg and larvae density with local physical factors (temperature, water velocity) chemical (phosphate, total nitrogen, ammoniac nitrogen) as indicators of productivity in the environment, abiotic factors (densities of phytoplankton and zooplankton), and with regional factors (the river level and rainfall), as they form favorable conditions and locations for their development and survival in the earlier stages of fish life. Ichthyoplankton samples were conducted in 14 points along the river, with subsurface water of 20 and 40 cm deep, with cylinder-type nets of 300 μm. Concomitantly, were collected samples of phytoplankton and zooplankton, and measured the local and regional variables. After the data collecting, the samples were sorted out and identified to the lowest taxonomic level possible. To evaluate differences in densities of eggs and larvae in the localities and in the months of study, ANOVA for repeated measurements was applied. Spearman correlation was used for the analysis of densities of eggs and larvae with regional and local variables. To evaluate larval densities with densities of phytoplankton and zooplankton we also used the Spearman correlation, however, this test was done with larvae that were identified at the level of genus and species, and later, with each species of migrating fish larvae. To analyze the composition of the structure of assemblies of larvae through the densities at the localities, we applied the partial Mantel test, between the distances of similarities, environmental and geographic distances. To evaluate the temporal difference between the groups of Characiformes and Siluriformes, we applied an ANOVA for repeated measurements. A direct ordering of the migratory larvae densities in sampling points was done. The spatial results with egg densities (F1;10= 0,572; p=0,467), and larvae (F1;10= 3,494 ; p=0,091) were not significant. Temporal results with egg densities (F3;30= 0,533; p=0,663) were not significant, however for the larvae (F3;30= 4,539; p=0,009) the results were significant with peaks in November and January. There was a significant correlation between larval densities and total nitrogen (r=-0,127; p=0,025) and the water temperature (r=0,292; p=0,035). The partial Mantel test has shown that the environmental variation was not a determining factor in the distribution of the taxonomic composition of groups along the basin (r=-0,214; p=0,966). The larvae assemblies show significant geographic dependence (r=0,459; p=0,001), the closer the dots geographically, the more similar were the taxonomic compositions. Taxonomic results show significant temporal difference (F3;48= 3,994; p=0,012) between groups of Siluriformes and Characiformes.

This study was prompted by the need to remedy the situation that existed with respect to the poor status of our knowledge regarding the ichthyoplankton assemblage of the nearshore region along the south-east Cape coast of South Africa. The first chapter provides a brief introduction to the field of ichthyoplankton research and includes a summary of the status of research in southern Africa and an explanation of early life history terminology. The selection of all sample sites, times and strategies is also outlined. The study area along the south-east Cape coast with respect to its location, climate and physical oceanography is described in the second chapter, as is the gear used, bongo nets and an RMT1x6. A sampling protocol for the use of bongos from a small ski-boat, and the RMT from the research vessels, and for the handling and processing of samples was established. The selection of Middlebank as the main monthly sampling site within the Tsitsikamma National Park (TNP) was based on taxonomic diversity as well as logistical and safety constraints. The effect of mesh size and time of sampling with bongo nets on the catchability of ichthyoplankton was investigated in chapter three. Most data was accumulated during Sea Fisheries research cruises, with additional collections coming from the National Parks vessel. Although the differences were not significant, the 505 μ mesh nets captured larger larvae, with catches comprising higher percentages of flexion and postflexion larvae. Larval concentration and size were consistently greater in samples from periods of reduced light intensity, but significant differences were the exception. It was decided that sampling with 505 μ mesh nets during daylight would provide a representative sample of the available ichthyoplankton assemblage, while at the same time being the most practical and least time consuming with respect to handling, clogging and backflushing. In chapter four, the early life history stages of thiny of the seventy-five taxa sampled are described, reflecting the paucity of information which existed on the ichthyoplankton of the nearshore zone in the south-east Cape. These descriptions are seen as an important contribution towards any future research efforts in the region, but as many of these descriptions are based on few or single specimens, it is realised that the description of egg and larval stages will be an ongoing process. Based upon the data collected during this study, an ichthyoplankton species checklist was established in chapter five. Seventy-five taxa of fish larvae were identified to either family, genus or species level. A number of squid para-larvae were also encountered. Similarities and discrepancies with a previous survey in the region are presented. The temporal distribution of eggs and larvae between August 1993 and October 1996 was established, and the spatial distribution of ichthyoplankton along an offshore transect was determined between January 1995 and May 1996. Only 7 species from Middlebank and twelve from all stations combined displayed seasonal trends, with most of these being prevalent during winter months. Egg production, both over Middlebank and from all stations combined, appeared to be consistent, with no seasonal trends. Based upon the results from the offshore transect samples, it would appear that a single ichthyoplankton assemblage exists from Storms River out to fifteen nautical miles. Although a variety of statistical methods were applied to the data during this study, low egg and larval concentrations and a low sampling frequency meant that results had to be interpreted carefully. Chapter six describes the preliminary investigation into the vertical distribution of eggs and larvae. During two research cruises, discrete depth sampling using an RMT1x6 net was performed, with the majority of samples being accompanied by physical data provided by a CTD rosette sampler. No definite patterns could be seen as larval concentrations were low, and the short time scale did not allow for the identification of any diel migratory patterns. The relationship between total larvae and the physical environment was poor. The only possible relationship was that between plankton volume and total egg and total larval concentrations. The TNP may play an important role in the conservation of reef fish and the seeding of nearby fishing grounds through the export of pelagic eggs and larvae. Chapter seven describes a preliminary investigation into the dispersal potential of ichthyoplankton from the TNP. Based upon longshore currents determined from drogues, ADCP vectors and current meter readings, it was clear that if larvae were passive drifters, the potential for their dispersal from the TNP did exist. This pilot study showed that future work should concentrate not only on the oceanographic aspects, but on behavioural aspects of larvae which may enhance or retard dispersal. In the final discussion, it is emphasised that while this study went a long way to increasing our knowledge of the nearshore ichthyoplankton community, the true picture of the temporal and spatial dynamics of the species assemblage may only be revealed once more intensive sampling has been performed. The resolution of the early life history stages of the sparids and the identification of eggs to species level are seen as priorities for the near future. A complete species checklist for the TNP is provided based upon previous surveys (both on adult and larval fishes), this work and personal observations. A total of 171 species of fish from 70 families were identified, illustrating that the eggs and larvae of many species in the TNP have yet to be sampled. A brief description of the collaborative effort which is envisaged for the TNP over the next few years is provided.

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Made available in DSpace on 2017-02-16T16:11:23Z (GMT). No. of bitstreams: 1 Maviael Fonseca Castro.pdf: 1233142 bytes, checksum: c58b8e4b654dcc4d3c2792e185684e2b (MD5) Previous issue date: 2005-02-28
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Qualitative and quantitative surveys of ichthyoplankton are essential to understand the role of eggs and larvae in the pelagic food web and to indicate preferred spawning season and season. Salinity variation may be a primary factor influencing patterns of fish distribution along gradients of an estuarine environment, as well as temperature. Therefore, to better understand the variability of an ecosystem's processes, an analysis of these at different scales of space and time is fundamental. This work aimed at the identification, statistical, biological and ecological evaluation of the ichthioplankton assembly in the Rio Formoso estuary; Being one of the few that is in good condition in the state of Pernambuco. The studied area corresponds to that covering the estuarine complex of the Formoso river, south coast of state (08º 35 '00''S and 035º 95 '00''W), 85 Km from the city of Recife. The material was collected in the period from January to December / 2001 using a 0.5 mm-mesh conical-cylindrical mesh, 30 cm in diameter and 2.0 m in length, and a flowmeter was attached to it. The collections were carried out in the different phases and periods of tides, covering all the dynamics of the waters in the estuary. In the 39 collection campaigns carried out, 399 trawls were carried out, capturing a total of 2,875 fish larvae, 4,120 eggs and 691 juveniles. The occurrence of 30 taxa was identified. Those with the highest median abundance were: Anchovia clupeoides, Atherinella brasiliensis, Bathygobius soporator, Bairdiella ronchus and Gerreidae, with relative participation of 27%, 14%, 12%, 9% and 7%, respectively; Also occurring some species of oceanic habit, such as Hirundichthys affinis, and others difficult to catch, such as Microdesmus bahianus.
Os levantamentos qualitativos e quantitativos do ictioplâncton são essenciais para compreender o papel dos ovos e larvas na teia alimentar pelágica e para indicar local e época preferenciais de desova. A variação da salinidade pode ser um fator primário que influencia nos padrões de distribuição de peixes ao longo de gradientes de um ambiente estuarino, assim como a temperatura. Portanto, para melhor entender a variabilidade de processos de um ecossistema, é fundamental uma análise destes em diferentes escalas de espaço e tempo. Este trabalho objetivou a identificação, avaliação estatística, biológica e ecológica da assembléia ictioplanctônica no estuário do rio Formoso; sendo este um dos poucos que se encontra em bom estado de conservação no estado de Pernambuco. A área estudada corresponde àquela abrangendo o complexo estuarino do rio Formoso, litoral sul de estado (08º 35’ 00’’S e 035º 95’ 00’’W), a 85 Km da cidade de Recife. A coleta do material foi realizada no período de janeiro a dezembro/2001 com a utilização de rede cônico-cilíndrica com malha de 0,5 mm, com diâmetro de 30cm na boca e 2,0m de comprimento, sendo acoplada a esta um fluxômetro. As coletas foram realizadas nas diferentes fases e períodos de marés, abrangendo toda a dinâmica das águas no estuário. Nas 39 campanhas de coleta realizadas, foram efetuados 399 arrastos, capturando um total de 2.875 larvas de peixes, 4.120 ovos e 691 juvenis. Foiidentificada a ocorrência de 30 taxa. Aqueles de maior abundância mediana foram: Anchovia clupeoides, Atherinella brasiliensis, Bathygobius soporator, Bairdiella ronchus e Gerreidae, com participação relativa de 27%, 14%, 12%, 9% e 7%, respectivamente; ocorrendo ainda algumas espécies de hábito oceânico, como Hirundichthys affinis, e outros de difícil captura, como Microdesmus bahianus.

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Fundação Araucária
This study describes the development and allometric growth patterns of larval Piaractus mesopotamicus from induced reproduction. From hatching until the 19th day, twenty individuals were selected for eight stage of development (yolk sac larval, preflexion, initial of flexion, flexion, end of flexion and post flexion). Later, morphometric measurements were taken of each individual: total length, head length, trunk length, tail (post anal) length, head height, body height, muscle height at anus leveleye diameter, mouth length, caudal peduncle height and caudal peduncle length. Allometric growth coefficients were calculated by linear regression; the changes in the coefficients of growth relate to ontogenetic changes in the priorities of the larvae. During the developmental stages of larval yolk and pre-flexion (mean CT = 3.363 and 5.89 mm), the larvae showed an evident priority for feeding and swimming capabilities. From the flexion stage (mean CT = 9.33 mm) was observed a change in growth priorities, especially those relating to body height, important characteristic for this species. From the post-flexing stage (mean CT = 16.25 mm) a greater propensity to isometry was evident for all coefficients growths. These results confirm the informations that there are different growth patterns for priority functions during ontogeny initial larvae. This study of morphometric and allometric growth of larvae Piaractus mesopotamicus, may assist the fisheries biology, supporting management strategies and conservation of natural populations
Este estudo descreveu o desenvolvimento e os padrões de crescimento alométrico de larvas de Piaractus mesopotamicus provenientes de reprodução induzida. Desde a eclosão até o 19° dia, vinte indivíduos foram selecionados para oito estágios de desenvolvimento (larval vitelino, pré-flexão, início de flexão, flexão, final de flexão, início de pós-flexão, pós flexão e final de pós-flexão). Posteriormente, foram tomadas medidas morfométricas: comprimento da cabeça, comprimento do tronco, comprimento da cauda anal posterior, altura da cabeça, altura do corpo, altura do músculo em nível do ânus, diâmetro do olho, comprimento da boca, altura do pedúnculo caudal e comprimento do pedúnculo caudal. Os coeficientes de crescimento alométrico foram calculados por meio de regressões lineares; as alterações ocorridas nos coeficientes de crescimento referem-se as mudanças nas prioridades ontogenéticas das larvas. Durante os estágios de desenvolvimento de larval vitelino e pré-flexão (média CT= 3,36 e 5,89 mm) as larvas apresentaram uma evidente prioridade para as capacidades de alimentação e natação. A partir do estágio de flexão (média CT= 9,33 mm) foi observada uma mudança nas prioridades de crescimento, principalmente as relacionadas com a altura do corpo, característica importante para essa espécie. No estágio de pós-flexão (média CT=16,25 mm) uma propensão maior a isometria ficou evidente, para todos os coeficientes de crescimentos. Esses resultados confirmam as informações de que existem padrões diferenciados de crescimento para funções prioritárias durante a ontogenia inicial de larvas. Este estudo sobre morfometria e crescimento alométrico das larvas de Piaractus mesopotamicus, poderá auxiliar a biologia pesqueira, subsidiando as estratégias de manejo e conservação das populações naturais

O presente trabalho teve como objetivo principal descrever a distribuição espaço-temporal do ictioplâncton da região do cabo Frio (RJ) em relação aos processos físicos de mesoescala, com ênfase na distribuição vertical. A amostragem foi realizada em verão e inverno de 2001, com o N/Oc. Prof. W. Besnard, durante dois cruzeiros do projeto DEPROAS. O ictioplâncton foi coletado com rede Multinet, com 5 redes de 333 m, sendo que cada estrato amostrado teve 20 m, até os 100 m de profundidade. Em laboratório, foram realizadas a triagem do ictioplâncton e identificação das larvas. A análise dos dados foi realizada através de testes estatísticos paramétricos e não paramétricos e análises multivariadas. Não houve um padrão claro de distribuição vertical das larvas em função das classes de comprimento, salvo em alguns casos particulares, como Bregmaceros cantori que teve maior frequência de larvas em pré-flexão associadas à termoclina e também baixa frequência de larvas em pós-flexão próximas à superfície. O padrão de distribuição do ictioplâncton foi determinado, em parte, pelas porcentagens de ACAS, de AC e a concentração de clorofila-a, tanto nos dois períodos. Com base nos resultados obtidos, foi possível demonstrar a influência direta dos processos físicos de mesoescala (i.e. ressurgência e subsidência) e dos padrões de distribuição de clorofila-a sobre a distribuição vertical do ictioplâncton na região do cabo Frio.
The aim of the present work was to describe the spatial and temporal distributions of the ichthyoplankton in the cabo Frio (RJ) region in relation to mesoscale physical processes, with emphasis on its vertical distribution. Samples were taken in the summer and winter 2001 onboard the R/V Prof. W. Besnard, during the two sampling surveys of the DEPROAS project. The ichthyoplankton was collected using a Multinet device with 5 nets of 333 mm meshed; being that each layer had 20 m up to 100m depth. Ichthyoplankton sorting and larvae identification were done in the laboratory. Data analyses were performed using parametric and non-parametric statistical tests, and also multivariate analyses. A clear vertical distributional pattern of larvae in relation to their length classes was not observed, except in some particular cases such as Bregmaceros cantori, which had a higher frequency of pre-flexion larvae associated to the thermocline and also a low frequency of pos-flexion larvae near the surface. The distributional pattern of ichthyoplankton was determined in part, by the percentages of SACW, CW and chlorophyll-a concentration in both periods. Based on these results, it was possible to demonstrate the direct influence of mesoscale physical processes (i.e. upwelling and downwelling) and chlorophyll-a distribution patterns on the vertical distribution of the ichthyoplankton in the cabo Frio region.

Os objetivos deste estudo foram descrever a composição taxonômica e distribuição horizontal das larvas de Serranidae na Plataforma Continental Sudeste Brasileira (PCSE), e verificar a interferência dos fatores ambientais e bióticos na distribuição larval. O material provém de 10 cruzeiros oceanográficos realizados nos meses de janeiro, maio, setembro e dezembro de 1975 a 1981, entre cabo Frio (RJ) e cabo de Santa Marta Grande (SC) e depositados na \"Coleção Biológica Prof. E. F. Nonato\". As larvas de Serranidae (933) foram identificadas em 14 táxons (Diplectrum formosum, Diplectrum spp., Serranus spp., Epinephelus itajara, Epinephelus morio, Epinephelus nigritus, Epinephelus tipo 1, Epinephelus spp., Mycteroperca spp., Pseudogramma gregoryi, Rypticus spp., Anthias menezesi, Hemanthias vivanus, Pronotogrammus martinicensis), distribuídos em nove gêneros e três subfamílias (Serraninae, Anthiinae, Epinephelinae). Com exceção de D. formosum, que apresentou ampla distribuição na plataforma interna da PCSE, e Epinephelus tipo 1 e Hemanthias vivanus, que se distribuíram preferencialmente na região sul da PCSE, os demais táxons se distribuíram na região norte da PCSE (cabo Frio-RJ a São Sebastião-SP), não ultrapassando a isóbata de 200 m. Os fatores salinidade, distância das ilhas e latitude foram significativos na distribuição de Diplectrum formosum, Diplectrum spp., Serranus spp., Epinephelus tipo 1, e Mycteroperca spp., táxons mais abundantes. Foi obtido um avanço na identificação de Epinephelus (E. morio, E. itajara e E. nigritus) e ratificada a morfologia dos espinhos alongados de E. nigritus.
This study describes the taxonomic composition and horizontal distribution of Serranidae larvae along Southeastern Brazilian Continental Shelf (SBSC), and investigates how environmental and biological factors influence the larval distribuction. The samplers, deposited in the Marine Biological Collection \"Prof. E. F. Nonato\", were collected on the 10 survey cruisers conducted on january, may, september and december from 1975 to 1981, between cape Frio (RJ) to cape Santa Marta Grande (SC). Larvae of Serranidae (933) were identified into 14 taxa (Diplectrum formosum, Diplectrum spp., Serranus spp., Epinephelus itajara, Epinephelus morio, Epinephelus nigritus, Epinephelus tipo 1, Epinephelus spp., Mycteroperca spp., Pseudogramma gregoryi, Rypticus spp., Anthias menezesi, Hemanthias vivanus, Pronotogrammus martinicensis), included in nine genera and three subfamilies (Serraninae, Anthiinae and Epinephelinae). Except for Diplectrum formosum, that was widely distributed throughout the southeastern continental shelf, and Epinephelus type 1 and Hemanthias vivanus, that were distributed into the south portion of the SBSC, other taxa distributed into the north portion of the SBSC (from cape Frio to São Sebastião), not exceeding the 200 m isobath. The salinity, latitude and distance of islands were significant factors in the horizontal distribution of Diplectrum formosum, Diplectrum spp., Serranus spp., Epinephelus type 1 and Mycteroperca spp., most abundant taxa. A significant progress was considered in identifying grouper larvae (Epinephelus morio, Epinephelus itajara and Epinephelus nigritus) and ratified the morphology of the elongated spines of E. nigritus.

One of the most sensitive life periods for each species is the first life stages (larval and juvenile). The survival rates of pelagic fish larvae in these phases are usually very low and subject to fluctuations, consequently affecting the recruitment of new generations. From historical Tuna landing data, the stock's abundance is fluctuating, especially for Atlantic Bluefin Tuna (ABT) (Thunnus thynnus, Linnaeus, 1758) Eastern stock. It is the largest Mediterranean Tuna and one of the most expensive species in the world. Some studies hypothesized that the fluctuations are dictated by environmental factors, particularly in the early life stages. Therefore, it appears necessary to better understand the reproductive biology, structure of the reproductive population, and the recruitment processes related to the environmental drivers of the Mediterranean Sea. In fact, it is a crucial area for maintaining ABT at a global level. It is essential for the other two species too, which share time and space during spawning in summer and their first life stages: ABT, Albacore Tuna (Thunnus alalunga, Bonnaterre, 1788), and Bullet Tuna (Auxis rochei, Risso, 1810). They carry out an essential ecological role as top predators, are fisheries targets globally, and have a fundamental influence on the structure and function of marine communities. Therefore, their sustainable management is essential and depends on a better understanding of the fish ecology, especially early life-history (LH) traits. Despite the Strait of Sicily (Central Mediterranean Sea) being an important spawning site for Tuna species, little is known about the relationship between the environmental variables and their larval spatial distribution in this area. Using historical larval collections from seven yearly surveys, in-situ environmental measurements, and satellite data, in this thesis, the interaction between ecological conditions and Tuna LH traits, horizontal distribution and spatial structure of the three Tuna species at the larval stage has been modelled. A multidisciplinary approach involving lagrangian simulations, species distribution modelling, and morphometric analysis has been used to verify the influence of environmental conditions on the distribution pattern of Tuna spawning and its effects on larval development and, consequently, on their survival probability. Finally, the potential impacts of the identified main driver have been investigated through forecasting models to determine the Tuna larval habitat patterns under possible future climate change scenarios. Understanding what influences the growth and survival of individuals among large pelagic fish populations, particularly during the larval stage, is crucial because these factors will eventually determine recruitment variability and the number of survivors that reach the adult stage. This work aims to improve knowledge of the growth and survival of Tuna larval stages, casting the complex system of the Central Mediterranean Sea in a new light. A site where upwelling, gyres, and fronts play a key role and observations could indicate a meta-population structure in Tuna populations. Chapter 1 provides an introduction with a background on the topic of study. Chapter 2 is a work published during my PhD candidate career. It is the basis for the characterization and knowledge of the central Mediterranean larval habitat. The abundance and presence-absence of larval specimens for the three Tuna species were modelled to examine their relationships with environmental factors. The results suggest that temperature, salinity, and day of the year are the key factors for understanding these species' ecological mechanisms and geographical distribution in this area. In Chapter 3, we look back in time and evaluate the conditions experienced by larvae, starting from their hatching to the point at which we found them. In this way, it was possible to better know the larval habitat and the spawning areas selected by the adults. We hypothesized that the environments experienced along the passive transport period would affect the development of these organisms. It seems helpful to describe not the difference in morphometric measurement but an early or late development. This work also highlighted different spatial patterns between the species. Finally, in Chapter 4, predictive models have been structured to model recruitment under different future climate change scenarios. Thanks to these models, it was possible to verify how the proportion of species could change. Despite the potential habitat seeming to expand, the abundances do not always follow the same trend. The results of this study can help manage future adult stocks and understand recruitment patterns under different future climate change scenarios. In fact, thermal sensitivity is a fundamental physiological attribute and one of the main reasons for induced changes in natural communities.
One of the most sensitive life periods for each species is the first life stages (larval and juvenile). The survival rates of pelagic fish larvae in these phases are usually very low and subject to fluctuations, consequently affecting the recruitment of new generations. From historical Tuna landing data, the stock's abundance is fluctuating, especially for Atlantic Bluefin Tuna (ABT) (Thunnus thynnus, Linnaeus, 1758) Eastern stock. It is the largest Mediterranean Tuna and one of the most expensive species in the world. Some studies hypothesized that the fluctuations are dictated by environmental factors, particularly in the early life stages. Therefore, it appears necessary to better understand the reproductive biology, structure of the reproductive population, and the recruitment processes related to the environmental drivers of the Mediterranean Sea. In fact, it is a crucial area for maintaining ABT at a global level. It is essential for the other two species too, which share time and space during spawning in summer and their first life stages: ABT, Albacore Tuna (Thunnus alalunga, Bonnaterre, 1788), and Bullet Tuna (Auxis rochei, Risso, 1810). They carry out an essential ecological role as top predators, are fisheries targets globally, and have a fundamental influence on the structure and function of marine communities. Therefore, their sustainable management is essential and depends on a better understanding of the fish ecology, especially early life-history (LH) traits. Despite the Strait of Sicily (Central Mediterranean Sea) being an important spawning site for Tuna species, little is known about the relationship between the environmental variables and their larval spatial distribution in this area. Using historical larval collections from seven yearly surveys, in-situ environmental measurements, and satellite data, in this thesis, the interaction between ecological conditions and Tuna LH traits, horizontal distribution and spatial structure of the three Tuna species at the larval stage has been modelled. A multidisciplinary approach involving lagrangian simulations, species distribution modelling, and morphometric analysis has been used to verify the influence of environmental conditions on the distribution pattern of Tuna spawning and its effects on larval development and, consequently, on their survival probability. Finally, the potential impacts of the identified main driver have been investigated through forecasting models to determine the Tuna larval habitat patterns under possible future climate change scenarios. Understanding what influences the growth and survival of individuals among large pelagic fish populations, particularly during the larval stage, is crucial because these factors will eventually determine recruitment variability and the number of survivors that reach the adult stage. This work aims to improve knowledge of the growth and survival of Tuna larval stages, casting the complex system of the Central Mediterranean Sea in a new light. A site where upwelling, gyres, and fronts play a key role and observations could indicate a meta-population structure in Tuna populations. Chapter 1 provides an introduction with a background on the topic of study. Chapter 2 is a work published during my PhD candidate career. It is the basis for the characterization and knowledge of the central Mediterranean larval habitat. The abundance and presence-absence of larval specimens for the three Tuna species were modelled to examine their relationships with environmental factors. The results suggest that temperature, salinity, and day of the year are the key factors for understanding these species' ecological mechanisms and geographical distribution in this area. In Chapter 3, we look back in time and evaluate the conditions experienced by larvae, starting from their hatching to the point at which we found them. In this way, it was possible to better know the larval habitat and the spawning areas selected by the adults. We hypothesized that the environments experienced along the passive transport period would affect the development of these organisms. It seems helpful to describe not the difference in morphometric measurement but an early or late development. This work also highlighted different spatial patterns between the species. Finally, in Chapter 4, predictive models have been structured to model recruitment under different future climate change scenarios. Thanks to these models, it was possible to verify how the proportion of species could change. Despite the potential habitat seeming to expand, the abundances do not always follow the same trend. The results of this study can help manage future adult stocks and understand recruitment patterns under different future climate change scenarios. In fact, thermal sensitivity is a fundamental physiological attribute and one of the main reasons for induced changes in natural communities.

Utilizando-se materiais coletados durante qua-tro cruzeiros oceanográficos com o N/Oc .\"Prof. W. Besnard\", na região Sudeste do Brasil, compreendida entre Cabo Frio (RJ) e Florianópolis (SC), de janeiro de 1980 a março de 1982, foram realizados estudos quali quantitativos so-bre ocorrências de larvas de peixes, relacionando-as com fatores abióticos. Problemas concernentes aos processos de amostragem tambem foram verificadas. Realizaram-se dois tipos de arrastos: arrasto oblíquo com a rede Bongo usando-se malhagens de 0,333 mm (fina) e de 0,505 mm (regular), e arrasto horizontal de superfície com a rede de Neuston, de 0,333 mm de malhagem. Em cada estação oceanográfica, alem das amostras biologicas, efetuaram-se as medições de temperatura e coleta de água para determinação de salinidade. Um total de 35.090 larvas foram analisadas, incluíndo as coletas das redes fina e regular da Bongo e a rede de Neuston. Dentre estas, 61 grupos diferentes foram separados, chegando a níveis específicos em alguns casos.- Dois gêneros e quatro especies foram identificados pela primeira vez na região: Saurida spp, Hygophum spp, Trachinocephalus myops, Synodus foetens Bregmaceros can-tori e Maurolicus muelleri. As famílias predominantes foram Clupeidae, Engraulidae, Myctophidae e Gonostomatidae. De uma maneira geral, a região Sudeste apresentou grande riqueza em taxa, mas com o predomínio de poucos grupos, em termos de abundância. Análises da relação entre larvas de peixes e fatores abióticos revelaram a existência de padrões de ocorrência e distribuição próprios para cada espécie, dentro de uma determinada faixa de variaçao de temperatura e de salinidade. Estudos realizados durante uma estação fixa de 36 horas em Cabo Frio, mostraram uma situação típica da estrutura oceanográfica da região, notando-se mudanças de massas de água no local, devido ao fenômeno da ressurgiê-cia. Este fator, associado ao horário de coleta, deve ter exercido influência de maneira complexa sobre o componen-te biológico, induzindo mudanças na ocorrência de diferentes tipos de larvas. Dois transectos, um ao largo de Cabo Frio e ou-tro ao largo de paranaguá, foram analisados com o intuito de obter-se informações a respeito da ocorrência e distribuição de larvas de acordo com a distância da costa. Os dados hidrográficos comprovam a existincia de diferentes massas de água compondo a estrutura oceanográfica daregião, que por sua vez influenciam a ocorrência e distribuição de larvas. A família Gerreidae teve a maior abundância associada à massa costeira. Sardinella brasiliensis, Harenguia jaguna e Engraulis anchoita foram de distribuição tipicamente nerítica, assim como as famílias Sciaenidae, Bleniidae, Ophidiidae, Carangidae e Cynoglossidae. Por ou-tro lado, Myctophidae, Gonostomatidae, Paralepedidae e Scombridae ocorreram preferencialmente na região ocêanica, que sofre influência da Corrente do Brasil. Análise do material coletado com a rede de Neuston comprovam a importância deste tipo de amostragem su-perficial para os estudos relacionados com o ictioplâncton, uma vez que esta rede captura uma porcentagem da população que é subamostrada pela rede Bongo. Observou-se a tendência de estratificação na camada superficial, principalmete de formas jovens, como no caso de Sardinella brasiliensis. Um aspecto especialmente notável foi o caso das fa-mílias Mugilidae e Mullidae em que a captura se deu significativamente em maior número no arrasto de superfície do que no arrasto oblíquo. Comparando-se os materiais coletados com as re-des finas e regular da Bongo, pôde-se verificar dois pro-blemas relacionados com a seletividade: o entupimento da rede e o escape de larvas menores através da malhagem. Ecomparando-se os materiais coletados durante os períodos diurno e noturno, pôde-se verificar o outro problema importante de seletividade, que é a fuga da boca da rede de larvas maiores. As nossas amostragens parecem nao ter sido afetadas pelo problema de entupimento, como mostram as análises do volume de água filtrada. Já o escape de lar-vas menores foi constatado em vários grupos, tendo sido de terminado para três especies o tamanho a partir do qual este problema começa a se tornar evidente: 7,5 mm para Sardinella brasiliensis e 6,5 mm para Harengula jaguana e Engraulis anchoita. A fuga da boca da rede ocorreu em lar-vas maiores durante o dia, concluindo-se que este problema varia conforme a especie, o padrão de migração vertical e o desenvolvimento do sistema visual.
Four oceanographic cruises have heen carried out off the southeastern Brazilian coast from Cabo Frio (23ºS) to Florianópolis (27°S) during the period from January 1980 to March 1982 by the R/V\" Prof. W. Besnard ,\". Fish larvae taken during these cruises were analysed and influences of abiotic factors on their occurrence were discussed.Problems regarding the sampling process were also discussed. Two kinds of sampling gears were used: Bongo nets fitted with a 0.505 mm and 0.333 mm mesh nets for oblique tow and Neuston net with a 0.333 mesh net for surface horizontal tow. At each sampling station, hydrographic data were sampled in addition to biological data. Total of 35,090 larvae were analysed. Sixty one groups were classified and some dominant ones were identified to spec1es level. Larvae belonging to two genera and four species were identified for the first time in the region under observation, i. e. Saurida spp., Hygophum spp., Synodus foetens, Trachinocephalus myops, Bregmaceros cantori and Maurolicus muelleri. The most abundant families were clupeidae, Engraulidae, Myctophidae and Gonostomatidae. In general, the ichthyoplankton from the southeastern Brazilian coast showed a large variety of larvae, but just few groups were outstandingly abundant. Analysing the relations between occurrence of fish larvae and hydrographic parameters, we found specific distri-bution patterns for each species. At the fixed station off Cabo Frio (22°59\'S; 042º05\'7W), 36 hour observations have been done and biological and hydrographic data have been collected every two hours. A change in the local oceanographic structure during the survey period has been observed along with wind induced coastal upwelling. A change of the oceanographic conditions associated with sampling time, may have influenced the occurrence of fish larvae. In order to obtain information on the distribution patterns of fish larvae in relation to distance from the coast, the samples collected on two transects off Cabo Frio and paranaguá were analysed. The presence of four different water masses in this region was confirmed and the occurrence and distribution of larvae seems to have close relationship with those water masses. Larvae of the family Gerreidae were more abundant in the coas tal water mass and those of Sardinella braziliensis, Harengula jaguana and Engraulis anchoita showed typical neritic distribution. Larvae belonging to the families Sciaenidae, Blenniidae, Ophídiidae, Carangidae and Cynoglossidae also showed the same distribution pattern. On the other hand, larvae belonging to the families Myctophidae, Gonostomatidae, Paralepedidae and Scombridae occurred mainly in the oceanic region where the influence of the Brazil Current is eminent. The ichthyoplankton collected at surface layer with Neuston net showed quite different types and size composition of fish larvae, In comparison with those taken with Bongo nets. Clear tendency of stratification in size composition at the surface layer was observed on some species (e.g. S.braziliensis). Larvae belonging to the families Mugilidae and Mullidae seems to be more concentrated at the surface layer, since they were more frequently sampled with the Neuston neto Three problems related to selectivity of plankton net (clogging, extrusion and avoidance) can be studied compar1ng the materials collected with the Bongo ets fitted with different mesh size nets and sampled at different times of the day. As shown in Figs. 23 and 24, there is no evidence of clogging of the fine mesh net during this survey. On the other hand, the extrusion of smaller larvae was confirmed for many groups and it was observed at sizes smaller than 7.5 mm, 6.5 mm, and 6.5 mm, respectively for S.brasiliensis, H.jaguana and E. anchoita. The avoidance was more remarkeble during the day time for larger larvae, but this problem varies depending on spec1es, migration pattern, and development stage of the visual system of each larvae

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The species Steindachneridion melanodermatum is an endemic fish to the Iguaçu River basin. Has great potential for pisciculture, however its initial development is still unclear, which limits the progress in the cultivation of this species. In this way, this study aimed to characterize the development ontogenetic of Surubim-do-iguaçu. The eggs larvae were obtained by induced spawning performed at the Experimental Station of Ichthyological Studies of the Ney Braga Power Plant (Salto Segredo Power Plant), Energy Company of Paraná (COPEL), between the months of January to March 2009. The morphometric and meristic variables were analyzed in 529 eggs, 370 larvae in preflexion, flexion and postflexion stages, and 117 juveniles. The eggs are spherical, transparent and non-adhesive, have an average diameter of 3.17 mm, perivitelline space of 0.96 mm and 2.12 mm calf. The larvae hath 33 hours and 30 minutes after fertilization (26.5° C). The larvae have a fusiform body without pigmentation initial, median eyes, intestine that goes beyond the middle portion of the body and the number of total myomeres ranged from 42 to 48. The juveniles resemble an adult, with a standard length of 28.43 mm and pigmentation formed by chromatophores punctiform irregularly distributed throughout the body
A espécie Steindachneridion melanodermatum é um peixe endêmico a bacia do rio Iguaçu que apresenta um grande potencial para a piscicultura, porém seu desenvolvimento inicial ainda é pouco conhecido, o que limita os progressos no cultivo desta espécie. Dessa forma, o presente estudo teve como objetivo caracterizar o desenvolvimento ontogenético do Surubim-do-iguaçu. Os ovos e larvas foram obtidos através de desovas induzidas realizadas na Estação Experimental de Estudos Ictiológicos da Usina Ney Braga (Salto Segredo), Companhia Paranaense de Energia (COPEL), entre os meses de janeiro e março de 2009. Foram analisadas as variáveis morfométricas e merísticas em 529 ovos, 370 larvas em diferentes estágios (pré-flexão, flexão e pós-flexão) e 117 juvenis. Os ovos são esféricos, transparentes e não adesivos, apresentam um diâmetro médio de 3,17 mm, espaço perivitelino de 0,96 mm e vitelo de 2,12 mm. A eclosão ocorreu 33 horas e 30 minutos após a fertilização a uma temperatura de 26,5 °C. As larvas apresentam um corpo fusiforme, sem pigmentação inicial, olhos medianos, intestino que ultrapassa a porção mediana do corpo e o número de miômeros totais que varia entre 42 48. Os juvenis se assemelham a um adulto, com um comprimento padrão de 28,43 mm e pigmentação formada por cromatóforos puntiforme distribuídos irregularmente pelo corpo

Com o objetivo de investigar a influência das massas de água sobre a distribuição horizontal e vertical das larvas de Myctophidae e de analisar a condição nutricional, o crescimento e a mortalidade de Myctophum affine, amostragens foram realizadas através de arrastos oblíquos (rede bongô) e estratificados (rede Multinet), em águas do sudeste brasileiro, desde a costa até o talude, entre cabo de São Tomé (RJ) e ilha de São Sebastião (SP). A intrusão da Água Central do Atlântico Sul diminuiu a extensão da Água Tropical (AT) sobre a plataforma. Como as larvas de Myctophidae foram associadas à AT, esse processo reduziu a ocorrência dessas larvas na plataforma. As espécies apresentaram diferentes padrões de distribuição vertical e horizontal, ressaltando a importância da identificação em nível taxonômico específico para a obtenção de um padrão de distribuição mais refinado. A análise histológica dos hepatócitos de Myctophum affine, a espécie mais abundante, evidenciou que a maioria das larvas estava em boa condição nutricional; apenas aquelas nos estágios menos avançados apresentavam sinais de inanição severa. Sua taxa de crescimento média (0,33 mm/dia) foi considerada intermediária entre os mictofídeos e a duração de seu período larval uma das menores. A taxa de mortalidade (11,8%) ficou abaixo da média obsevada para espécies de peixes marinhos, sendo similar a de alguns epipelágicos da região. Dessa forma, a alta abundância, baixa taxa de mortalidade e boa condição nutricional das larvas de M. affine mostraram que essa área é um importante berçário para essa espécie, e provavelmente para outros mictofídeos.
In order to investigate the influence of water masses on the horizontal and vertical distribution of Myctophidae larvae and to analyze the nutritional condition, growth and mortality of Myctophum affine, oblique and stratified tows were done using bongo net and Multinet respectively, in the southeastern Brazilian Bight, between São Tomé cape (RJ) and São Sebastião island (SP) from the coastal region to the continental slope. The intrusion of South Atlantic Central Water (SACW) reduced the extent of Tropical Water (TW) over the shelf. As Myctophidae larvae were associated with TW, this process reduced larval abundance in the shelf. Species showed different patterns of vertical and horizontal distribution, emphasizing the importance of identification at species level to obtain a more detailed distribution pattern. Histological analysis of hepatocytes of the M. affine, the most abundant species, showed that the majority of larvae was in good nutritional condition; only those in early stages presented signs of severe starvation. The average growth rate of the M. affine (0.33 mm/day) was considered intermediate among lanternfishes, and the duration of its larval period is among the shortest one. The mortality rate (11.8%) was below average compared with other marine fish species, but it was similar to some epipelagic fishes that occur in the region. Therefore, high abundance, low mortality rate and good nutritional condition of M. affine larvae, showed that this is an important nursery area for this species, and probably to other lanternfishes.

The main objective of this dissertation was to evaluate long-term fluctuations in the distribution and abundance of Engraulis anchoita eggs and larvae in the Southeastern Brazilian Bight (SBB). Engraulis anchoita is a fish species that is ecologically and economically important. We analyzed samples and abiotic data from eighteen oceanographic cruises conducted during austral late spring and early summer from 1974 to 2010. Two different stocks were detected in the SBB based on egg size, with the predominant stock in the area having smaller eggs than the stock in the region further south. Using indicative kriging, we identified occasional (e.g. Florianópolis - 27°S and off Santos Bay) and avoided (e.g. off São Sebastião Island and off Cananéia-Iguape Coastal System) spawning sites. Through zero-inflated models, spatial factors (different areas and the local depth) were related to the probability of sampling false zeros and temporal and oceanographic conditions (different years and temperature) with egg and larvae abundance. We also described faster and more accurate methodology to identify E. anchoita eggs, and compared the mesh-size efficiency to sample eggs and analyzed how egg size varied seasonally. Our results may support future studies and may assist a future fishery management of E. anchoita, a species not yet exploited in the SBB.
O principal objetivo dessa tese foi analisar as flutuações de longo-prazo na distribuição e abundância de ovos e larvas de Engraulias anchoita, uma espécie de peixe de importância econômica e ecológica, na Plataforma Continental Sudeste do Brasil (PCSE). Nós analisamos amostras e dados abióticos de dezoito cruzeiros oceanográficos realizados durante o fim da primavera e o começo do verão de 1974 a 2010. Dois estoques distintos foram identificados com base no tamanho dos ovos, um predominante e com menor tamanho e outro de maior tamanho ao sul da PCSE. Através de \"krigagem\" indicativa, foram identificadas áreas de desova ocasional (como ao norte de Florianópolis e a área ao largo da baía de Santos) e áreas em que a desova foi evitada (como em frente à Ilha de São Sebastião e ao Sistema Costeiro Cananéia-Iguape). Usando modelos inflacionados de zeros, os fatores espaciais (diferentes áreas e profundidades amostradas) foram relacionados com a probabilidade de se amostrar falso zero, enquanto os fatores temporais e oceanográficos (diferentes anos e temperatura) foram relacionados com a abundância de ovos e larvas. Apresentamos também uma metodologia mais rápida e mais eficiente para identificar os ovos de E. anchoita, comparamos as amostragens realizadas com duas malhagens diferentes e analisamos variações sazonais do tamanho dos ovos capturados. Assim, nossos resultados poderão auxiliar estudos futuros e também no manejo pesqueiro da espécie em questão, ainda não explorada comercialmente na área de estudo.

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The heterogeneity of the habitat assumes that structurally complex habitats can increase the diversity of species. In aquatic environments these complex habitats also play an important role in the biological diversity, in the interspecific relations and in the system s productivity. Studies have shown that several fish species seek sites with structured habitats for their reproduction. This study intends to evaluate the influence of the structural complexity provided by submerged trees on the ichthyplankton in the influence area of two reservoirs located in Parana River basin, demonstrating the importance of such sites known as paliteiros. The samples were carried out in places with and without the presence of submerged trees from October 2009 to March 2010. For these samples, we used plankton nets with mesh size of 0.5mm equipped with a measurer to obtain the volume of filtered water. The process was realized with continuous drag, using two plankton nets. We determined the abundance of larvae, number of species, Shannon s diversity index and the indicator taxons for each environment analyzed. To determine if there were any significant spatial variation we applied the t-test. The composition of the ichthyoplanktonic assemblage in the different environments was summarized based on a correspondence analysis (CA). During the study 122,099 individuals were captured, belonging to 22 species, six orders, 19 families. Within this sample, 78.84% are individuals captured in environments without any structure, whereas 21.16% are individuals captured in structured environments. In both places the most abundant species were Hypophthalmus edentatus and Plagioscion squamosissimus. The places with submerged trees presented the highest values in richness and abundance of species, which indicates that spawning may have been occurring in headwaters located in areas with submerged vegetation, and that eggs, as well as larvae, are passively carried by water flows to development areas, located at lower areas in the reservoir. This study indicates that areas with submerged vegetation play a very important part in fish reproduction in the sampled reservoirs and, therefore, their preservation may be indispensable for the future presence of many fish species in these environments.
A heterogeneidade do habitat assume que habitats estruturalmente complexos podem aumentar a diversidade de espécies, em ambientes aquáticos esses habitats complexos também tem importante papel na diversidade biológica, nas relações interespecíficas e na produtividade do sistema. Estudos têm demonstrado que, várias espécies de peixes procuram locais com habitats estruturados para se reproduzirem. Assim, este estudo teve por objetivo avaliar a influência da complexidade estrutural fornecida pelas árvores submersas sobre a assembleia ictioplanctônica na área de influência de dois reservatórios da bacia do rio Paraná, demonstrando a importância dos paliteiros para a reprodução da ictiofauna. As amostragens foram realizadas em locais com e sem a presença de árvores submersas nos reservatórios de Mourão e Itaipu, entre os meses de outubro de 2009 a março de 2010. Para as coletas foram utilizadas redes de plâncton cônico-cilindricas de malha 0,5mm equipadas com medidor de fluxo para obtenção do volume de água filtrada, o processo foi realizado em arrasto contínuo, com uso de duas redes de plâncton. Foram determinadas as abundâncias de larvas, o número de espécies (riqueza), o índice de diversidade de Shannon e determinado os táxons indicadores para cada ambiente analisado através do valor indicador. Para determinar se houveram diferenças espaciais significativas entre as médias dos atributos avaliados foi aplicado um teste t. A composição da assembleia ictioplanctônica nos diferentes ambientes foi sumarizada a partir de uma análise de correspondência (CA). Durante o estudo foram capturados 122.099 indivíduos, pertencentes a 22 espécies, seis ordens, 19 famílias. Destes, 78,84% foram indivíduos capturados em locais sem estrutura, enquanto 21,16% foram capturados em locais estruturados. Para ambos os locais as espécies mais abundantes foram Hypophthalmus edentatus e Plagioscion squamosissimus. Os locais sem árvores submersas tiveram os maiores valores de riqueza e abundância de espécies o que indica que, as desovas podem estar ocorrendo nas áreas de cabeceira e que tanto os ovos como as larvas são passivamente transportados por correntes de água para áreas de desenvolvimento, localizadas em áreas inferiores do reservatório. Esse estudo demonstrou que, trechos com vegetação submersa desempenham importante papel na reprodução dos peixes na área dos reservatórios amostrados e, por tanto, sua preservação pode ser indispensável para a representação futura de muitas espécies de peixes nesses ambientes.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The aim was to detect morphometric differences in the stages of larval development Hemisorubim platyrhynchos and Pseudoplatystoma corruscans and allometric growth in these two fish species of ecological and economic relevance in South America Larvae were separated into six stages of development ontogenetic larval (yolk sac larval, preflexion, initial of flexion, flexion, end of flexion and post flexion). That allowed Landmarks grouping them in three series of geometric distances. Was applied to PCA for each series of distances between different stages of larval development of both species to examine the morphometric patterns (similar or not). The factorial analysis of variance (species and stage of development) was used above retained axes of PCA for interpretation of data and test the possible differences. To verify the existence of allometric pattern in species, the scores generated by the first axis of PCA was used to estimate the multivariate allometric coefficients. The series I from PCA segregated (H. platyrhynchos and P. corruscans) the species and stages (larval yolk and pre-flexion). In the series II H. platyrhynchos showed no differences between the larval stages, but for P. corruscans was marked development from the flexion stage to the late flexion allowing a separation of H. platyrhynchos. In post-flexion stage (series III) morphometric discrimination between species was not evident. In relation to the allometric growth, the increase regions-median cephalic and caudal was accentuated in the early stages of both species in question, tending to isometry as the species developed. This work was possible morphometric differentiation of species in larval stages of development, aside from a post-flexion.
O objetivo deste trabalho foi detectar diferenças morfométricas entre as larvas de Hemisorubim platyrhynchos e Pseudoplatystoma corruscans em diferentes estágios de desenvolvimento larval, como também no crescimento alométrico dessas duas espécies de peixes de relevância econômica e ecológica na América do Sul. As larvas foram separadas em seis estágios de desenvolvimento larval ontogenético (larval vitelino, pré-flexão, início de flexão, flexão, final de flexão e pós-flexão), determinando marcos anatômicos que possibilitaram agrupá-las em três séries de distâncias geométricas. Para encontrar possíveis padrões morfométricos (similar ou não) entre as larvas das duas espécies nos diferentes estágios de desenvolvimento foi aplicada a Análise de Componentes Principais (ACP) para cada série de distâncias. A análise de variância bifatorial (espécies e estágio de desenvolvimento) foi usada sobre os eixos retidos da ACP para a interpretação dos dados e testar as possíveis diferenças. Para verificar a existência de padrão alométrico nas espécies, os escores gerados pelo eixo 1 da ACP foram utilizados para estimar os coeficientes alométricos multivariados. A ACP para a série I separou as espécies (H. platyrhynchos e P. corruscans) e estágios (larval vitelino e pré-flexão). Na série II H. platyrhynchos não mostrou diferença entres os estágios larvais, porém para P. corruscans ocorreu desenvolvimento acentuado a partir do estágio de flexão ao final de flexão, possibilitando a separação de H. platyrhynchos. No estágio de pós-flexão (série III), a separação morfométrica entre as espécies não foi evidente. As espécies são distintas morfometricamente especialmente nos estágios iniciais de desenvolvimento larval, diferenças atribuídas principalmente ao formato e volume do saco vitelino à eclosão e ao tamanho das larvas, apesar de algumas similaridades nos padrões de crescimento de diferentes regiões do corpo. O crescimento alométrico das larvas correspondeu a eventos do desenvolvimento e comportamentais observados na ontogenia inicial das espécies. Este estudo sobre morfometria geométrica e crescimento alométrico das larvas de H. platyrhynchos e P. corruscans poderá auxiliar as pesquisas em biologia pesqueira, subsidiando as estratégias de manejo e conservação das populações naturais.

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Itaipu Binacional
The study of initial stages of the lifecycle of the fish is important for understanding the success of species in the environment and determine areas and spawning periods. This study analyzed the composition and structure of the assembly of fish larvae in a region of the last lotic stretch of the Paraná River at Ilha Grande National Park, searching for differences in spatial and temporal patterns of abundance, richness, diversity of larvae and indicator taxa and to examine the possible influence of some abiotic factors on the catch. Samples were taken monthly at night and six consecutive breeding seasons (October-March) between 2001 and 2008 (periods I, II, III, IV, V and VI) in three different environments (river, lake and tributaries). To this end, we used networks of conical-cylindrical plankton mesh 0.5 mm, equipped with a flowmeter to obtain the volume of filtered water. Simultaneously to the data were obtained at water temperature, dissolved oxygen, electrical conductivity and pH. Besides these, were also obtained data on the river level and rainfall. Was determined, besides the abundance of larvae, the number of species (richness), the diversity index of Shannon and the specific indicator taxa for each environment and periods analyzed using the indicator value (IndVal). To determine whether there were significant differences between the biotic, was applied to analysis of variance of main effects (ANOVA, one-way) and Tukey's test, modified for number of elements between different groups (Unequal) to determine which levels differed. To assess the relationship of environmental variables and abundances was applied to multiple regression analysis. The assemblage of fish larvae of the National Park of Ilha Grande was composed for the most part by bodies covered by the order Characiformes. Periods I and IV were the highest density of larvae, while the latter showed the highest richness and diversity of species. The indicator species of the periods were mostly sedentary, but Rhinelepis aspera and Salminus brasiliensis, captured in the (V and I, respectively) higher river level and rainfall. Between environments, pond was significantly different from tributaries and the catches were quite high, with high wealth and low diversity. Among indicator species of this environment, we find migratory and non migratory species. The House of larvae was related to water temperature, pH, dissolved oxygen, river level and rainfall. It was then possible to observe the existence of spatial and temporal differences in assemblage structure and composition of larvae in the region of the Ilha Grande National Park, mainly related to the characteristics of the study sites and environmental factors. It was observed further that lentic provided favorable characteristics for development of both sedentary species as migratory, while the tributaries are apparently being used as a migratory route and spawning areas due to capture of newly hatched larvae, demonstrating the importance of adopting measures to protect these types of environment, not only in the region of Ilha Grande National Park, but throughout the remainder of the lotic stretch of the floodplain of the Paraná River.
O estudo das fases inicias do ciclo de vida dos peixes é importante para entendimento do sucesso das espécies no ambiente e determinar áreas e períodos de desova. Este estudo analisou a composição e a estrutura da assembleia de larvas de peixes em uma região do último trecho lótico do rio Paraná, no Parque Nacional de Ilha Grande, buscando a existência de diferenças espaciais e temporais nos padrões de abundância, riqueza, diversidade de larvas e táxons indicadores, bem como analisar possíveis influências de alguns fatores abióticos sobre as capturas. As amostragens foram noturnas e realizadas mensalmente em seis períodos reprodutivos (outubro a março) entre 2001 e 2008 (períodos I, II, III, IV, V e VI) em três ambientes distintos (rio, tributários e lagoa). Para tanto, foram utilizadas redes de plâncton cônico-cilíndricas de malha 0,5 mm, equipadas com fluxômetro para a obtenção do volume de água filtrada. Concomitantemente às amostragens, foram obtidos dados de temperatura da água, oxigênio dissolvido, condutividade elétrica e pH. Além destes, também foram obtidos dados referentes ao nível fluviométrico e pluviosidade. Foram determinadas, além das abundâncias de larvas, o número de espécies (riqueza), o índice de diversidade de Shannon e determinado os táxons indicadores para cada ambiente e períodos analisados através do valor indicador (IndVal). Para determinar se houve diferenças significativas entre os fatores bióticos, foi aplicada a análise de variância de efeitos principais (ANOVA; one-way) e o teste de Tukey, modificado para número de elementos distintos entre grupos (Unequal) para determinar qual nível diferiu. Para avaliar a relação das variáveis ambientais e as abundâncias foi aplicada a análise de regressão múltipla. A assembleia de larvas de peixes do Parque Nacional de Ilha Grande foi composta em sua maior parcela por organismos enquadrados na ordem Characiformes. Os períodos I e IV foram os de maior densidade de larvas, sendo que o último apresentou a maior riqueza e diversidade de espécies. As espécies indicadoras dos períodos foram na maioria sedentárias, com exceção de Rhinelepis aspera e Salminus brasiliensis, capturadas nos períodos (V e I, respectivamente) de maior nível fluviométrico e pluviosidade. Entre os ambientes, lagoa foi significativamente diferente de tributários e as capturas foram bastante elevadas, com alta riqueza e baixa diversidade. Dentre as espécies indicadoras deste ambiente, encontramos espécies migradoras e não migradoras. A assembleia de larvas esteve relacionada com a temperatura da água, pH, oxigênio dissolvido, nível fluviométrico e pluviosidade. Com isso foi possível observar a existência de diferenças espaciais e temporais na composição e estrutura da assembléia de larvas na região do Parque Nacional de Ilha Grande, principalmente relacionadas às características dos ambientes amostrados e aos fatores ambientais. Foi possível observar ainda que os ambientes lênticos proporcionaram características favoráveis ao desenvolvimento tanto de espécies sedentárias como de migradoras, enquanto que os tributários aparentemente estão sendo utilizados como rota migratória e áreas de desova devido a captura de larvas recém eclodidas, demonstrando a importância da adoção de medidas visando a proteção destes tipos de ambiente, não só na região do Parque Nacional de Ilha Grande, mas em todo o remanescente do trecho lótico da planície de inundação do alto rio Paraná.

Fish larvae are particularly sensitive to a number of factors and, since larval survival may directly influence future abundances of adult stocks, understanding how larval survival and populational fluctuations affects the yearly recruitment strength and spatial distribution of populations becomes of key importance. The main objectives of this research were to perform a taxonomic characterization of the ichthyoplankton collected along the Cacheu river, assess its biodiversity and how it fluctuates with environmental variability. To achieve this, we performed a taxonomical identification and quantification of fish larvae, down to the lowest possible taxonomic level, collected from zooplankton sampling tows at four stations along the Cacheu river, in the Republic of Guinea-Bissau (RGB). With the abundance data gathered from this, we assessed the biodiversity within the estuary and how environmental factors (i.e.: depth, O2 saturation, salinity, and temperature) drove each taxon’s distribution along the stream. Our results have shown that there seems to be no correlation between the variation of larval abundance and that of the environmental factors. However, the overall abundance was observed to decrease with depth, increase from upstream to downstream and to have different distributions in each season. We found 10 taxa in our samples: Atherinidae (no previous records of presence in the area), Carangidae, Clupeidae, Congridae, Gobiidae, Mugilidae, Syngnathidae, Clupeiformes, Heterosomata (Pleuronectiformes), and Elops. Overall, Gobiidae larvae represented the majority of the fish larvae identified, followed by Clupeidae and Carangidae. The relative difference in abundances between Clupeidae and Carangidae is in accordance with two previous studies undertaken off the coast of the RGB, however the predominance of Gobiidae is not, which may be due to the sampling environment of the present study being estuarine whereas in both previous studies it was marine. This appears to be the first study regarding taxonomic characterization of ichthyoplankton (more specifically, fish larvae) within an estuarine environment, in the RGB, and may thusly be of significance in aiding the characterization of the biodiversity of the Cacheu river, providing a baseline reference for future taxonomic studies within it.
As larvas de peixe são particularmente sensíveis a vários factores e, como a sobrevivência larvar pode influenciar directamente as futuras abundâncias dos stocks adultos, torna-se particularmente importante compreender como a sobrevivência larvar e as flutuações populacionais afectam a força do recrutamento anual e a distribuição espacial de populações. Os principais objectivos deste estudo foram a caracterização taxonómica do ictioplâncton do rio Cacheu, a aferição da sua biodiversidade e de como esta varia com a variabilidade ambiental. Para este propósito, procedeu-se à identificação taxonómica e quantificação de larvas de peixe, até ao nível taxonómico mais baixo possível, capturadas em amostragens de zooplâncton realizadas em quatro estações de amostragem ao longo do rio Cacheu, na República da Guiné-Bissau (RGB). Com os dados de abundância recolhidos, foi aferida a biodiversidade dentro do estuário e a forma como os factores ambientais (i.e.: profundidade, saturação de O2, salinidade e temperatura) impulsionaram a distribuição de cada táxon ao longo do curso de água. Os resultados demonstraram que parece não haver uma correlação entre a variação da abundância larvar e a dos factores ambientais. No entanto, observou-se que a abundância geral diminui com a profundidade, aumenta de montante para jusante e tem distribuições diferentes em cada estação do ano. Foram encontrados 10 taxa: Atherinidae (sem registos prévios de presença nesta zona), Carangidae, Clupeidae, Congridae, Gobiidae, Mugilidae, Syngnathidae, Clupeiformes, Heterosomata (Pleuronectiformes) e Elops. No geral, as larvas de Gobiidae representam a maioria das larvas de peixe identificadas, seguidas por Clupeidae e Carangidae. A diferença relativa de abundâncias entre Clupeidae e Carangidae está em concordância com dois estudos anteriores, levados a cabo ao largo da costa da RGB, mas a predominância de Gobiidae não, o que pode dever-se ao facto de o meio de amostragem deste estudo ser estuarino, enquanto em ambos os estudos anteriores o meio era marinho. Este parece ser o primeiro estudo dedicado à caracterização taxonómica de ictioplâncton (ou mais concretamente, larvas de peixe) dentro de um ambiente estuarino na RGB e poderá assim ter importância no auxílio da caracterização da biodiversidade do rio Cacheu, fornecendo uma base de referência para futuros estudos taxonómicos neste rio.
Mestrado em Biologia Marinha Aplicada

Indiana University-Purdue University Indianapolis (IUPUI)
Recently there has been a lot of effort in developing systems for sampling and automatically classifying plankton from the oceans. Existing methods assume the specimens have already been precisely segmented, or aim at analyzing images containing single specimen (extraction of their features and/or recognition of specimens as single targets in-focus in small images). The resolution in the existing systems is limiting. Our goal is to develop automated, very high resolution image sensing of critically important, yet under-sampled, components of the planktonic community by addressing both the physical sensing system (e.g. camera, lighting, depth of field), as well as crucial image extraction and recognition routines. The objective of this thesis is to develop a framework that aims at (i) the detection and segmentation of all organisms of interest automatically, directly from the raw data, while filtering out the noise and out-of-focus instances, (ii) extract the best features from images and (iii) identify and classify the plankton species. Our approach focusses on utilizing the full computational power of a multicore system by implementing a parallel programming approach that can process large volumes of high resolution plankton images obtained from our newly designed imaging system (In Situ Ichthyoplankton Imaging System (ISIIS)). We compare some of the widely used segmentation methods with emphasis on accuracy and speed to find the one that works best on our data. We design a robust, scalable, fully automated system for high-throughput processing of the ISIIS imagery.

The study and the analysis of marine ecosystems is a significant part of the marine science research. These systems are valuable resources for fisheries, improving water quality and can even be used in drugs production. The investigation of ichthyoplankton inhabiting these ecosystems is also an important research field. Ichthyoplankton are fish in their early stages of life. In this stage, the fish have relatively similar shape and are small in size. The currently used way of identifying them is not optimal. Marine scientists typically study such organisms by sending a team that collects samples from the sea which is then taken to the lab for further investigation. These samples need to be studied by an expert and usually end needing a DNA sequencing. This method is time-consuming and requires a high level of experience. The recent advances in AI have helped to solve and automate several difficult tasks which motivated us to develop a classification tool for ichthyoplankton. We show that using machine learning techniques, such as generative adversarial networks combined with transfer learning solves such a problem with high accuracy. We show that using traditional machine learning algorithms fails to solve it. We also give a general framework for creating a classification tool when the dataset used for training is a limited dataset. We aim to build a user-friendly tool that can be used by any user for the classification task and we aim to give a guide to the researchers so that they can follow in creating a classification tool.

碩士
國立臺灣海洋大學
環境生物與漁業科學學系
97
This study was carried out in four cruises in December 2003 and February、May、August 2004 on board of the “Fishery Research Ⅰ” for understanding the seasonal variation of ichthyoplankton community in the southern East China Sea. The results showed that the hydrology condition of the southern China Sea had the seasonal characteristic and the spatial change. In December 2003, the temperature ranged from 17.7 to 23.7 degrees and the salinity fell from 32.12 to 34.61 psu. During the year of 2004, the temperature ranged from 15.5-24.8 degrees in February, 22.7-27.8 degrees in May, and 27.1-29.0 degrees in August.On the other hand, the salinity fell between 32.47 to 34.34 psu in February, 34.23 and 34.50 psu in May, and 34.02 to 34.29 psu in August. Total numbers of 2,274 larvae,which came from 24 samplings and was identified to 119 taxa and 76 families, were collected in this study. In the four sampling cruises, it was founded that the abundances of larval fish were highest, about 743.64 inds./1000m3 during late fall-winter and lowest, about 39.41 inds./1000m3 during late winter-spring The dominant species in each season were Gonostoma gracile (December, 2003), Trachurus japonicus (February, 2004), Sarda sp. (May, 2004) and Engraulididae (August, 2004). By the CCA (Canonical Correlation Analysis) we can suggest that the seasonal transformation, the structural characteristic include composition、diversity、evenness、concentration、richness and abundance etc. of the larval fish would also change.

碩士
國立中山大學
海洋資源學系研究所
88
Abstract: There were 75 families, 119 genera and 182 species of ichthyoplankton found in the adjacent areas of Kaohsiung and Liuchiu Yu Island. Fifty families, 82 genera and 111 species were collected in the surface waters, and 37 families, 54 genera and 68 species were collected in oblique tows to 100m with an open 1 m net, while 41 families, 48 genera and 73 species were collected by a multiple opening-closing net. Engraulis japonicus was the most dominant species, and was found all year round; other dominant species included coastal fish species (Apogonidae and Pomacentridae), anadromous species (Scombridae), oceanic species (Engraulidae and Myctophidae), and demersal species (Gobiidae). There were only 3 species of ichthyoplankton belonging to 3 genera and 2 families found in the Tapong Bay, all these species are benthic species. The coastal waters of Kaohsiung and Liuchiu Yu Island might be influenced both by the river and the topography of Kaping Trench, and thus the hydrological conditions of this area were more complex, and the ichthyoplankton was more diverse. On the other hand, the hydrological conditions of the semi-closed Tapong Bay changed less than that of the estuary of Kaoping river, thus the species composition of larval fish was simple and less diverse. Overall, the highest abundance of the ichthyoplankton in the adjacent areas of Kaohsiung and Liuchiu Yu Island was found in the wet season(June), with an average of 108± 116 ind./100 m3. E. japonicus was the most abundant in February, revealed that might be the breeding season of this species. Other dominant species (eg. Bregmaceros japonica and Tridentiger sp.) also showed significant seasonal variation. Higher abundance of ichthyoplankton was usually found in the entrance of Kaohsiung first harbor(St.1) and the estuary of Kaoping river(ie. St.4~6). No significant diel vertical migration of the ichthyoplankton was observed in this study. Most ichthyoplankton were found in the water column above 100 m during both day and night.

Estuaries play a key role as nurseries for fish larvae and are critical for the early life stages of fish development. However, these can be highly affected by direct human impacts as well as climate change. Climate variability distresses the ichthyoplankton assemblages with consequences in the marine pelagic food webs and fish populations biology (namely recruitment). This study aims to investigate the influence of environmental variability on interannual abundance of ichthyoplankton assemblages of the Mondego estuary (Portugal), on a long-term scale. For this, an ichthyoplankton sampling programme of 13 years (2003-2015) along six distinct sampling stations was analysed to evaluate spatial, seasonal and interannual changes of fish larvae distribution over periods of wet, regular and dry conditions. The larval fish community was dominated by Pomatoschistus spp. and Pomatoschistus microps across all seasons and precipitation regimes, with higher abundances of larvae occurring during summer and spring. Main changes on the ichthyoplankton community were related with species seasonality and phenology as well as a reduction on total larval abundance and an increase of marine species during extreme events. River flow, precipitation and consequently salinity appeared as the main factors influencing not only the abundance and number of species but also their distribution in the estuarine area, with a major appearance of marine species inside the estuary during dry periods.
Os estuários desempenham um papel crucial enquanto berçário para larvas de peixe sendo fundamentais durante as primeiras fases do ciclo de vida do desenvolvimento dos peixes. Os ecossistemas estuarinos são altamente afetados por impactos humanos e também por alterações climáticas. A variabilidade climática afeta as comunidades de ictioplâncton levando a alterações na cadeia trófica pelágica marinha e nos recursos pesqueiros (recrutamento). Este estudo tem como objetivo investigar a influência que a variabilidade ambiental tem nas alterações de abundância interanual de ictioplâncton no estuário do Mondego (Portugal). Para tal foi efetuado um programa de recolha de amostras ao longo de 13 anos (2003-2015) em seis locais de amostragem ao longo do estuário de modo a avaliar a distribuição espacial e sazonal das larvas de peixe relativamente a períodos de seca, chuvosos e regulares. A comunidade de larvas de peixe foi dominada por Pomatoschistus spp. e Pomatoschistus microps durante todas as estações do ano com abundância de larvas de peixe superior durante o verão e a primavera, independentemente das condições climáticas. As principais alterações à comunidade estão relacionadas com a sazonalidade e fenologia das espécies bem como uma redução na abundância total de larvas e um aumento de espécies marinhas durante eventos extremos. O caudal do rio, a precipitação e, consequentemente, a salinidade parecem ser os principais fatores a influenciar não só a abundância e o número de espécies, mas a sua distribuição dentro do estuário, com uma maior prevalência de espécies marinhas dentro do estuário durante anos secos.
Mestrado em Biologia Aplicada

博士
國立臺灣大學
動物學系
86
The area 24.5-27 oN and 120-123 oE off northeastern Taiwan was selected for ichthyoplankton study. It included the three watermasses--southern East China Sea (SECS), mixing zone (MIX) and Kuroshio (KUR) and thus three hydrographic ecotopes were identified. The seasonal variation of the fish fauna based on ichthyoplankton was analyzed. This study also applied the biological parameters of Japanese anchovy larvae, which hatch in early spring, to interpret the effects of the hydrographic dynamic on the recruitment of the population off northeastern Taiwan. The major purpose of this study were to explore the effects of water masses on the distribution, growth and nutritional condition of ichthyoplankton, and to clarify the variation of year stock in coastal fishery. A total of 327 ichthyoplankton samples were taken during 14 cruises from June 1989 to September 1992 in the waters off northeastern Taiwan. The density of ichthyoplankton was lowest in winter, increased in spring, reached the maximum in summer, and declined in autumn. Average densities of the ichthyoplankton in the 3 hydrographic ecotopes were highest in the SECS, moderate in the KUR, and lowest in the MIX. In total, 59 789 individuals of ichthyoplankton belonging to at least 124 families and 547 species were collected.The major ichthyoplankton species, comprising about 60% of the total catch, were distinctive in different seasons and waters. Decapterus spp. (14.0%) and Auxis spp. (6.2%) were abundant in spring; Auxis spp. (6.9%) and Benthosema pterotum (5.8%) in summer; B. pterotum (55.2%), gobiids (4.1%), and Synagrops sp. (3.2%) in autumn; and B. pterotum (15.4%) and Gonostoma gracile (7.5%) in winter. B. pterotum (23.0%) and Auxis spp. (5.1%) were abundanct in SECS; Decapterus spp. (28.6%) and Auxis spp. (7.1%) in MIX; and B. pterotum (5.6%) and Vinciguerria nimbaria (4.4%) in KUR. The dendrogram of these major ichthyoplankton species exhibits 7 species-associated groups. The survival of Japanese anchovy larvae is affected by water masses off northeastern Taiwan. Three conclusions were drawn from this study: 1. The RNA/DNA ratio of the larvae were different significantly among the hydrographic ecotopes. Based on the RNA/DNA ratios, the nutritional condition of Japanese anchovy larvae from the KUR was poorer than that from the SECS and MIX. The starvation probability was higher (27.9﹪) in the KUR than in the SECS (2.8﹪) and MIX (5.0﹪). 2. Indices of the fluctuating asymmetry (FA) were calculated for 3 otolith traits, i.e., mean absolute asymmetry (differences between right and left) maximum radius (MOR), perimeter (OP) and surface area (OA)). Mean absolute asymmetry in MOR and OP were not significantly different among the hydrographic ecotopes. Mean absolute asymmetry in OA was significantly different among the hydrographic ecotopes, greater in KUR than in the SECS and MIX. 3. According to the growth equation, the daily somatic and otolith growth of larval anchovy was faster in the KUR than in the MIX. The relative growth between the MOR and standard length was not significantly different among the hydrographic ecotopes. The length frequency distribution of the larval Japanese anchovy exhibited significant differences between year classes and among the hydrographic ecotopes.

博士
國立臺灣海洋大學
環境生物與漁業科學學系
102
In this study, nine cruises that stationed 287 times were conducted from June 2006 to October 2011 onboard Ocean Research I and II to investigate how ichthyoplankton assemblages are affected by the hydrological environment in the East China Sea. Principal components and canonical correlation analysis were used to illustrate the relationships between the abundance, composition, diversity, and dominant species of larval fish and the hydrological environment. Cluster analysis was implemented to examine the variation of ichthyoplankton assemblages and composition structure in the East China Sea. The spatial distribution of Engraulis japonicas and Benthosema pterotum, the two dominant species among the samples, are described in this study. Regarding hydrographic conditions, various structures in surface temperature were observed among the seasons, and significantly distinct salinity structures were observed during summers as caused by a runoff of diluted water from the Yangtze River (<31), indicating that hydrographic environments varied seasonally. Water from the Kuroshio Current, the Taiwan Strait, and the Yellow Sea was observed to seasonally meet in the East China Sea. The results indicated that water from the Kuroshio current and Taiwan Strait flowed into the continental shelf of the East China Sea during the summer, and that cold water flowed along the coast of Mainland China because of the southward flow of China’s coastal current with water from the Yellow Sea during the winter. In addition, during the summer, diluted water from the Yangtze River caused drastic changes. Regarding biological samples, 59,340 larval fish were collected from 174 stations. The larvae gathered comprised 401 taxa belonging to 139 families and 183 genera, yielding a total abundance of 176,862 ind./1,000 m3. The top nine dominant species of larval fish (>1%) included E. japonicus (70.61%), B. pterotum (7.91%), Sillago japonica (4.59%), Bregmaceros arabicus (1.49%), Setipinna tenuifilis (1.40%), Sigmops gracilis (1.32%), Saurida elongata (1.29%), Diaphus B group (1.15%), and Vinciguerria nimbaria (1.03%). The larval abundance exhibited a significant difference among seasons (Mann–Whitney U test, p < .05), but not between day and night in each cruise. In spring and summer, the two dominant species were E. japonicas (2.82–68.18%) and B. pterotum (2.30–3.14%), respectively, whereas the dominant species included S. gracilis (4.40–10.43%), and Diaphus A (3.14–6.31%) and B (4.94–11.93%) groups in autumn and winter. The average larval abundance range during spring and summer was between 738–2,716 ind./1,000 m3, which is higher than that during autumn and winter (150–753 ind./1,000 m3). Larval abundance was also associated with the environment except during autumn. It was significantly and positively correlated with temperature but negatively correlated with salinity in summer; moreover, it was positively correlated with chlorophyll in spring, and positively correlated with dissolved oxygen in winter. In addition, the abundance of fish larvae was significantly positively correlated with the runoff of the Yangtze River, which was the opposite effect on the abundance of zooplankton. The species richness of larval fish increased with salinity and surface temperature, but decreased with surface dissolved oxygen and zooplankton abundance. Evenness of larval fish was positively correlated with bottom temperature, but negatively correlated with chlorophyll a. Finally, six assemblages were recognized based on cluster analysis and water mass analysis. They were the coastal water group, Taiwan Strait water group, coastal mixed water group, Taiwan Strait mixed water group, Yellow Sea water group, and Kuroshio water group. The most dominant species of larvae in the Kuroshio group were the gonostomatid, phosichthyid, and myctophid species. During summer, the most dominant species in Taiwan Strait water were Auxis spp., B. pterotum, and Bregmaceros spp. In the same waters, the most dominant species in winter were Moolgarda spp. and scorpaenid; scorpaenid also appears in the Yellow Sea water group. In addition, we focused on the distribution of E. japonicas and B. pterotum, the two most dominant species in this survey. The former was positively correlated with chlorophyll a but negatively correlated with surface salinity. A substantial correlation was also observed between E. japonicas and the runoff of the Yangtze River; the distribution of this species was possibly influenced by the diluted water from the Yangtze River and the phases of the moon. The latter exhibited varied distribution depending on the development stage. In early development stages, a substantial and negative correlation was observed with surface dissolved oxygen and zooplankton abundance; in later development stages, a positive correlation was observed with chlorophyll a.

碩士
國立臺灣海洋大學
環境生物與漁業科學學系
96
This study was carried out in two cruises (CR1462 and 1463) from 31-July 2007 to 4-August 2007 on board of the “Ocean Research II”. We investigated the summertime diel assemblages of ichthyoplankton in the Pacific waters northeast of Taiwan. The range of water temperature was from 23.9 to 29.3�aC in the surface at the edge of upwelling, from 28.3 to 30.2�aC in the Kuroshio zone, and from 22.2 to 29.6�aC in the coastal area (I-Lan Bay). Salinity was higher in the Kuroshio zone than in the vicinity of upwelling and the I-Lan Bay. Total numbers of 2,863 larvae were collected from 3 stations, and 132 taxa contributing to 75 families were identified. The relationships of the ichthyoplankton assemblage between stations could be divided into 3 groups by Cluster Analysis. The most dominant species of each group were Diaphus B group (14%), Callionymidae (9%), Apogonidae (7%), Diaphus A group (6%), and Gobiidae (4%) at edge of upwelling zone; Diaphus B group (10%), Diaphus A group (10%), Cyclothone alba (7%), Serranidae (6%), and Vinciguerria nimbaria (4%) in the Kuroshio zone; Benthosema pterotum (22%), Hygophum proximum (14%), Callionymidae (13%), Gobiidae (11%), and Diaphus B group (5%) in the I-Lan Bay. The vertical migration of larvae was observed in Benthosema pterotum and Diaphus spp. The alternate migration of Diaphus A and B group suggested that separation of habitat at larval stage might be effective in reducing cannibalism.

碩士
國立臺灣海洋大學
環境生物與漁業科學學系
99
This study was carried out in three cruise in June , December 2009 and December 2010 on the board of the “ Ocean Research II ” for understanding the factual distribution of the fish larvae assemblage during the winter and summer time in the Southern East China Sea. The range of water temperature was varied from 17.08℃ to 27.86℃ in June 2009 , from 14.64℃ to 22.74℃ in December 2009, and from 16.21℃ to 23.60℃ in December 2010. The range of water salinity was from 32.39psu to 34.63psu in June 2009, from 30.08psu to 34.64psu in December 2009, and from 29.92psu to 34.66psu in December 2010. Total numbers of 2,317 larvae were collected from 27 stations, and 145 taxa contributing to 74 families were identified. The most dominant species in summer were Decapterus spp. (26.7%), SCIAENIDAE spp. (11.3%), and Auxis spp. (6.7%). The most dominant species in winter 2009 were Trichiurus lepturus (17.1%), Gonostoma gracile (12.4%), and Lampadena spp. (8.6%), and the most dominant species of winter in 2010 were Trichiurus lepturus (12.3%), Bregmaceros spp. (7.2%), and Gonostoma gracile (5.1%). In addition, the abundances of larval fish were 1279.57 ± 380.78 inds./1000m3, higher during summer than 234.56 ± 261.76 inds./1000m3 and 224.42 ± 216.71 inds./1000m3 during winter. By the ANOVA test, the species composition and abundances of larval fish in both season and mesh size were significant difference(p&lt;0.05). For the diversity, Shannon diversity and richness index were higher in summer, while evenness index were higher in winter. For the difference in the mesh size, Shannon diversity and richness index were highest in the mesh of 330μm, and evenness index were highest in the mesh of 1000μm. All the stations could be divided into summer and winter group. Four groups(A~D) were divided by the two-way cluster analysis. The A group species were included Schindleria spp., Trichiurus lepturus and Bregmaceros spp. while is dominated in winter, but fewer in summer. The B and D group species dominated in winter and summer, respectively were included Lampadena spp., Myctophum asperum and Gonostoma gracile, and SCIAENIDAE spp., Decapterus spp., Cynoglossus joyneri and Auxis spp.. The C group species were widely distributed included SCORPAENIDAE spp., Diaphus A group, MUGILIDAE spp. and Benthosema pterotum in summer and winter. It suggested that the spatial distribution of larval fish in summer was widely distributed, while it was aggregated and possibly influenced by Kuroshio current in winter.

碩士
國立臺灣海洋大學
環境生物與漁業科學學系
104
This study was tried to investigate summer ichthyoplankton assemblages associated with the hydrologic conditions in Changjiang estuary using the ORI net and CTD hydrological sampling from 2006 to 2014. 　　Sea surface temperature was varied between 17.61℃ and 28.41℃, while sea water surface salinity was ranged from 18.00 to 34.85. In addition, total number of 18729 fish larvae were collected from 27 stations, and 119 taxa contributing to 56 families were identified. The five most dominant species were Gobiidae spp. (42.81%), Engraulis japonicas (35.92), Benthosema pterotum (3.61%), Auxis spp.(2.64%), Cynoglossus spp. (2.1%) and Bregmaceros arabicus (1.80%). Their composition and average abundances of ichthyoplankton in six cruises were significantly different (p<0.05) while the abundances were varied between 1325.5 and 23151.6 ind/1000m3. 　　For the biology diversity including the Richness, Shannon and Evenness, these indices were decreased with the distance away from the coast. And the percentage for the development of larval life in Preflexion larva stage was the highest about 51.5%, proved the Changjiang estuary for a great nursery ground. 　　Four summer communities of fish larvae were recognized by cluster analysis as coastal group, continental shelf group, mixing group and central continental shelf group. The most dominant species in coastal group were Gobiidae spp. (89%), E. japonicas (4.32%). The most dominant species in continental shelf group were E. japonicas (70.93%), Auxis spp. (4.85%), B. pterotum (4.62%) and Gobiidae spp. (4.34%). And the most dominant species in mixing group were E. japonicas (13.16%), Cynoglossus spp. (11.56%), B. arabicus (8.42%), Gobiidae spp. (6.68%), Chaetodontidae spp. (5.56%) and Auxis spp. (5.41%). The Pearson correlation coefficient of dominant species with temperature and salinity indicated that the species of B. arabicus and B. pterotum like to inhabit at the relative high temperature and low salinity, as E. japonicas inhabit at the relative low temperature and salinity and Auxis spp. inhabit at the relative high temperature and salinity. It sugguested that change in hydrologic pattern could give response to the ichthyoplankton communities.