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1
Griffiths, Marc H. "The taxonomy and life-history of Argyrosomus japonicus and A. inodorus, two important sciaenids off the South African coast." Thesis, Rhodes University, 1996. http://hdl.handle.net/10962/d1005169.
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A study of the biology, anatomy and taxonomy of the sciaenid fishes of the genus Argyrosomus from South Africa and Namibia revealed that three species were confused under the name "Argyrosomus Izololepidotus (Lacepède 1801)". Comparison of morphometric and meristic data, otoliths, swim-bladders, drumming muscles, and other morphological features of specimens from southern Africa, Madagascar, the Mediterranean, the eastern Atlantic Ocean, Japan and Australia, revealed that "A. hololepidotus" is a complex of four species: A. japonicus (Temminck & Schlegel 1843), which occurs off southern Africa, Japan and Australia; A. inodorus sp. nov., which is known from Namibia to the Kei River (32°40'S) on the east coast of South Africa; A. coronus sp. nov., which is known from central and northern Namibia and Angola, and A. hololepidotus, which appears to be endemic to Madagascar. Both A. japonicus and A. inodorus are important recreational and commercial linefish species in South Africa. Although A. inodorus occurs on the east and west coasts of South Africa, and A. japonicus is found between Cape Point and Mozambique, the former species is abundant only between Cape Point and the Kei River, and the latter species from Cape Agulhas to northern KwaZulu/Natal. The life-histories of Argyrosomus japonicus and A. inodorus, within these respective ranges, were elucidated using length-at-age, reproductive, catch and effort, size composition, otolith dimension/fish length and tagging data. Median sizes at maturity (L₅₀) for A. japonicus were 920 mm TL (5 years) for males and 1070 mm TL (6 years) for females. All males >1100 mm TL (7 years) and all females >1200 mm TL (8 years) were mature. Females grew faster than males, but in both sexes growth slowed dramatically after maturity. Maximum age recorded was 42 years, but fish older than 27 years were rare. Adult A. japonicus were predominantly found in the nearshore marine environment, but also occurred in estuaries and in the surf zone. Spawning takes place in the nearshore environment, from August to November in Natal, and from October to January in the Southern and South-Eastern Cape regions. A large proportion of the adult population migrate to Natal to spawn, although spawning may continue once they return to the Cape. Early juveniles of 20-30 mm TL recruit into turbid estuaries along the entire east coast, possibly aided by olfactory cues. They appear to remain in the upper reaches of the estuaries where they find suitable food and refuge from predators until they grow to about 150 mm TL. Juveniles larger than this size were found in the middle and lower reaches of estuaries and also in the surf zone. Juvenile A. japonicus (<1000 mm TL) generally did not migrate long distances, but remained as separate sub-stocks until they reached maturity. A. inodorus grows more slowly than A. japonicus, and attains a lower maximum age (25 years) and a smaller maximum size (34 vs 75 kg). There was no significant difference between the growth rates of male and female A. inodorus. Those in the South-Westem Cape initially grew faster than those on the east coast, but growth slowed sooner in the former region with the result that these fish attained a smaller maximum size. Although ripe A. inodorus were sampled throughout the year, there was a distinct spawning season from August to December, with a peak in spring (Sept-Nov). Spawning occurred throughout the study area for this species, in <50 m depth. Size at sexual maturity for A. inodorus was smaller in the South-Eastern Cape than in the Southern Cape. Median size at maturity for females was attained at 310 mm TL (1.3 years) in the former and at 375 mm TL (2.4 years) in the latter region, and the length at which all females were mature was 400 mm (3.5 years) and 550 mm (4.7 years) respectively. For males the estimates of Lso and total maturity were 200 mm (1 year) and 400 mm (2.8 years) for the SouthEastern Cape and 250 mm (1.5 years) and 450 mm (3.4 years) in the Southern Cape. East of Cape Agulhas, A. inodorus was found from just beyond the surf zone to depths of 120 m. Adults occurred predominantly on reef (>20 m) while juveniles were found mainly over soft substrata of sand/mud (5-120 m depth). Early juveniles do not enter estuaries, but apparently recruit to nursery areas immediately beyond the backline of breakers (5-10 m depth), and then move seawards with growth. No juveniles were obtained from the area west of Cape Agulhas as substrates <200 m depth were unsuitable for trawling. Due to lower water temperatures, the adults in this area were found from within the surf zone to depths of only 20 m. East and west of Cape Agulhas there was evidence of offshore dispersal in winter, in response to oceanographic changes. Based upon otolith morphology, juvenile and adult distribution patterns, sizes at sexual maturity and on tagging data, A. inodorus between Cape Point and the Kei River apparently exist as three separate stocks, one in the South-Eastern Cape, one in the Southern Cape and one in the South-Western Cape, with limited exchange. The life-histories of A. japonicus and A. inodorus are discussed in terms of their management. The large size at maturity of A. japonicus together with evidence for considerable human impact on the early juvenile, juvenile, and the adult phases of the life-cycle indicate that estuarine nursery habitats need to be conserved, that the minimum size limit should be increased, and that current bag limits for this species should be reviewed. Although the current minimum size limit provides protection for A. illodorus until maturity, evidence is presented which indicates that at least one and possibly all of the stocks of this species are currently over-exploited. Stock assessment of the South African A. japonicus and A. inodorus resources, and the implementation of effective management strategies, are therefore a matter of urgency.
2
Farmer, Bryn Morgan. "Comparisons of the biological and genetic characteristics of the Mulloway Argyrosomus japonicus (Sciaenidae) in different regions of Western Australia /." Murdoch University Digital Theses Program, 2008. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20090716.94528.
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3
Hill, Gary. "Ontogeny of the Sexually Dimorphic Sonic Muscle in Three Sciaenid Species." W&M ScholarWorks, 1985. https://scholarworks.wm.edu/etd/1539617558.
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4
Ninin, Andressa Pinter dos Santos. "Morfologia e distribuição de peixes da família Sciaenidae no estágio de transformação na costa sul e sudeste do Brasil." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/21/21131/tde-29062009-160750/.
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No sudeste e sul do Brasil, os peixes da família Sciaenidae estão entre os peixes mais pescados sobre a plataforma continental interna. O conhecimento da ocorrência tanto espacial quanto temporal dos indivíduos na fase de transformação, que se estabelecem no local onde se desenvolverão, torna-se informação fundamental para o entendimento do ciclo de vida das espécies e, por extensão, para ações de preservação e de manejo de recurso. Porém, descrições das espécies de Sciaenidae na fase de transformação são escassas, impedindo a identificação desses peixes. Neste trabalho são estudadas 22 espécies das 28 de Sciaenidae do sudeste e sul do Brasil no estágio de desenvolvimento de transformação com base em material acumulado nas instituições que mantém coleções de peixe. Séries de crescimento de 16 dessas espécies foram morfologicamente descritas e ilustradas, bem como elaborada uma chave de identificação das espécies que ocorrem na área. A ocorrência espacial e temporal das amostras foram mapeadas, sendo estimada a época de nascimento e confrontada com a literatura sobre crescimento e reprodução. Foi observado que a maioria das espécies se restringe a estuários e baías, em águas rasas, havendo indícios de predomínio da época de nascimento (e portanto, de desova) no verão.In the southeast and south of Brazil, the Sciaenidae are among the most caught fishes on the shallow waters of the continental shelf. Spacial and temporal occurrence knowledge of individuals at the transformation stage is a fundamental information for understanding the life cycle of the species and, by extension, for preservation and management action. Morphological descriptions of Sciaenidae fishes at that developmental stage are scarce, preventing their taxonomic identification. In this work 22 species from the 28 of Sciaenidae in the southeast and south of Brazil are studied on the transformation stage based on material from the institutions that maintain collections of fish. Series of growth of 16 of these species were morphologically described and illustrated, as well as draft a key to identify the species that occur in the area. The spacial and temporal distribution of the samples were mapped, being estimated the time of birth and faced with the literature on growth and reproduction. It was observed that most species are strict to shallow waters of estuaries and bays, with evidence of the predominance of the time of birth (and therefore spawning) in the summer.
5
Hutchings, Kenneth. "Taxonomy, biology and management of South African sciaenid fish of the genus Umbrina." Doctoral thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/6704.
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This research was initiated in 2001 with the overall objective of providing scientific information relevant to the sustainable management of South African Umbrina species. Previously there was confusion over the identity and distribution of Umbrina species in South African waters and very little was known of their life histories, population dynamics and stock status. Morphological comparison of a large number of South African Umbrina (n = 369) with specimens from the type locality (Canary Islands) confirmed the identity of South African U canariensis Valenciennes, 1843, and allowed for an expanded description of the species. However, differences between specimens of U ronchus Valenciennes, 1843 and those of the second South African species, lead to the resurrection of U robinson; Gilchrist and Thompson 1908, as a valid name for this species. Spatial analysis of South African specimens collected with a variety of gear revealed U robinsoni to be a shallow water species found from the surf-zone to 40 m depth that is targeted by recreational shore anglers and spear fishers, whilst U canariensis occurs predominantly from 40-100m depth and is predominately landed as a by-catch in the inshore trawl fishery. Although both species occur throughout the South African eastern seaboard, U canariensis is most common west of the Kei River, where the continental shelf is wider.
6
Frehse, Fabrício de Andrade. "Estrutura populacional e dieta de Stellifer rastrifer (Jordan, 1889) e Stellifer brasiliensis (Schultz, 1945) (Scianeidae, Perciformes), nos periodos diurno e noturno, em quatro areas da plataforma sul do estado do Parana e norte do estado de Santa Cat." reponame:Repositório Institucional da UFPR, 2009. http://hdl.handle.net/1884/18392.
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7
Bernatzeder, Andrea Katinka. "Salinity induced physiological responses in juvenile dusky kob, Argyrosomus japonicus (Sciaenidae)." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1005163.
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Fisheries management regulations for dusky kob Argyrosomus japonicus, an important commercial and recreational fisheries species, have failed and the stock is considered collapsed. It is important to take an ecosystems approach to management which includes understanding the effect of environmental factors on recruitment, abundance and distribution. The distribution of early juveniles (20-150 mm TL) in the wild appears to be restricted to the upper reaches of estuaries at salinities below 5 psu. Food availability could not explain the distribution of early juveniles. The aim of this study was to investigate the role of salinity on the distribution of early juvenile dusky kob (<150 mm TL) by examining physiological responses of juveniles exposed to a range of salinities under laboratory conditions. The hypothesis was that the physiological functioning of early juveniles would be optimised at the reduced salinities which they naturally occur at. The objectives of this study were to investigate the effect of salinity on: i) plasma osmolality; ii) growth, food conversion ratio and condition factor; and iii) gill histology with emphasis on chloride cell size and number. A preliminary study was undertaken to determine whether the use of 2-phenoxyethanol had an effect on plasma osmolality. Juveniles pithed prior to blood sampling were used as the control. Plasma osmolality was not affected by exposure or duration of exposure (2, 4, 6, 8, 10 min) to 2-phenoxyethanol. The ability of teleosts to regulate plasma osmolality over a wide range of salinities indicates their degree of ‘physiological euryhalinity’. Plasma osmolality of juveniles exposed to 5, 12 and 35 psu was measured every two weeks over a total of six weeks. Although juveniles were able to regulate plasma osmolality over the duration of the experiment, plasma osmolality at 5 and 12 psu was significantly lower than in fish maintained at 35 psu. Growth is used as an indicator of the relative energy used for osmoregulation at different salinities, as the energy used for osmoregulation becomes unavailable for growth. A nineweek growth experiment was conducted on juveniles exposed to 5, 12 and 35 psu. Juveniles grew and survived at all three salinities. However, growth of juveniles at 5 psu was significantly lower than at 12 and 35 psu. Other than a significantly greater weight gain at 35 psu relative to 12 psu, there was no significant difference in specific growth and length gain between juveniles at 12 and 35 psu. Food conversion ratio and condition factor at 12 and 35 psu were not significantly different, but food conversion ratio and condition factor at 5 psu was significantly greater and lower than at 35 psu respectively. In fish, gills are considered the major organ involved in osmoregulation. Within the gills, chloride cells are the predominant site of ion exchange which is driven by the Na⁺, K⁺- ATPase enzyme. Gill samples of juveniles exposed to 5, 12 and 35 psu for six weeks were examined histologically using light microscopy. Chloride cells of juveniles maintained at 5 psu were significantly more abundant than in juveniles at 12 and 35 psu. Chloride cells of juveniles at 5 psu were significantly larger than in juveniles kept at 12 psu, but not significantly different to those of juveniles kept at 35 psu. The ability of the juvenile fish to regulate plasma osmolality indicates that they are 'physiologically euryhaline', but the reduced growth and proliferation of chloride cells at 5 psu suggests that energy expenditure for osmoregulation is increased at hypoosmotic salinities. Salinity induced physiological responses could therefore not explain the natural distribution of early juvenile dusky kob and it is proposed that other environmental factors (e.g. temperature) are also important. It is also hypothesised that the high conductivity of an estuary in South Africa, to which our understanding is limited, may negate the effect of reduced salinity. Although freshwater input into estuaries is an important factor, further investigations to explain the distribution and abundance of early juveniles is required to make management recommendations. Dusky kob is also becoming an increasingly popular aquaculture species in South Africa. In this regard, early juvenile dusky kob can be grown at salinities as low as 12 psu without negatively affecting growth and production.
8
Lazo, Juan Pablo. "Development of the digestive system in red drum (Sciaenops ocellatus) larvae /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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9
Williams, Christopher D. "Investigations into cataract formation in sciaenid fish species from the Elizabeth River, Chesapeake Bay, Virginia." W&M ScholarWorks, 1994. https://scholarworks.wm.edu/etd/1539616904.
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Cataract formation in the Elizabeth River (ER) has been reported since 1986. Previous studies have concentrated on describing cataract as a function of exposure to polluted sediments, especially polycyclic aromatic hydrocarbons (PAH). These studies, however, have not examined what processes might be involved in fish cataractogenesis. The overall objective of this research was to identify important processes associated with the early development of cataract in feral fish populations. Field studies were used to systematically examine cataract development. Cataract in sciaenids was not associated with previously described cataractogenic factors, but could be linked to contaminated sediments of the ER. Cataract was highly prevalent, first appeared at the visible center of the lens, varied in the degree opacification (&<&10-100%), could be classified into stages of development (stage 1-4), and inhibited lens growth. Furthermore, data showed that a positive association existed between bottom water temperatures (&\sp\circ&C) and cataract prevalence. Biochemical comparison of lenses revealed that the water content, cholesterol level, and free fatty acid composition were significantly elevated, total esters reduced, while no significant changes occurred in the protein composition of lenses with early cataract development. These data suggest that altered plasma membrane permeability might be involved in opacification. Investigations of cataract in fish at the cellular level have not been studied due to the absence of a reliable in vitro model. Protocols were established for the primary culture, successful passage (45 subcultures), and the long-term maintenance (54 months) of spot lens epithelial cells. Cells exhibited certain morphological characteristics, crystallin-protein composition, and chromosome complement indicative of epithelial cell differentiation and cell-line transformation. In vitro experiments indicated that both DNA and RNA indices were positively associated with cataract development in spot lenses. Results suggested that high molecular weight PAH may play a role in interfering with the mitotic cycle of epithelial cells. These results suggest that lens epithelial cells are disturbed and may be involved in the initial steps of cataractogenesis. In conclusion, results demonstrate that cataract development is associated with high levels of contamination found in the ER. Altered membrane permeability and epithelial cell function may play a key role in cataract initiation.
10
Horodysky, Andrij Z. "Comparative sensory and energetic ecology of sciaenid fishes and their competitors in Chesapeake Bay, VA." W&M ScholarWorks, 2009. https://scholarworks.wm.edu/etd/1539616699.
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Coastal fishes of the western North Atlantic, such as sciaenids and their competitors, support substantial commercial and recreational fisheries in waters that may vary widely in temperature, salinity, light intensity and spectral distrubution, and dissolved oxygen levels, yet their ecophysiological abilities to cope with such variability have received little attention. I therefore applied multidisciplinary comparative techniques to investigate aspects of the sensory and energetic ecophysiology of several sciaenid fishes and non-sciaenid competitors common in the western North Atlantic. Auditory brainstem response experiments demonstrated that sciaenid fishes have greatest auditory sensitivity at low frequencies that match their vocalizations. Based upon both anatomy and auditory bandwidths, most sciaenids appear to be hearing generalists that are likely sensitive to the particle motion components of aquatic sounds. Electroretinographic experiments revealed that the luminous sensitivities, temporal properties, and chromatic characteristics of the visual systems of phylogenetically-similar sciaenid fishes from different microhabitats, and those of phylogenetically-dissimilar piscivores from similar microhabitats, all correlated with lifestyle and ecology. The eyes of benthic and nocturnal fishes were typified by high luminous sensitivity, slow temporal resolution, and relative diel-invariance, consistent with foraging in dim photoclimates. By contrast, the eyes of pelagic diurnal piscivores had comparatively lower luminous sensitivity, higher temporal resolution, and exhibited higher diel variation, consistent with specific diurnal light niches. Accordingly, visually-foraging diurnal piscivores may be disadvantaged in eutrophied, turbid waters characteristic of many modern estuaries. Intermittent-flow respirometry experiments revealed that the majority of sciaenid fishes had resting and active metabolic rates similar to those of most teleost fishes but significantly lower than high-demand species such as tunas. However, the metabolic rates of kingfishes (Menticirrhus sp.) were significantly higher than other sciaenids, but significantly lower than those of tunalike fishes. Estimates of standard metabolic rate from power performance curves fitted to active metabolic rate data did not differ significantly from experimentally-derived measurements in static chambers, validating the experimental approach. Data from these chapters were analyzed with linear repeated measures and nonlinear mixed effects models that considered repeated measurement of subjects, modeled within-individual correlations, and the included random factors that improved the scope of inference. Although not novel approaches, these methods demonstrate quantitative advancements for future analyses of physiological data comprised of multiple measurements taken from individual experimental subjects. Collectively, the results of this dissertation underscore the potential power and utility of physiological techniques to provide a wide variety of information that may complement more traditional techniques used in fisheries science, particularly when coupled with appropriate analytical strategies. Sciaenid fishes are model organisms for investigations of the links between form, function, and the environment in coastal ecosystems.
11
Ma, Liang. "Genetic studies for aquaculture and stock-enhancement of red drum (Sciaenops ocellatus)." Texas A&M University, 2003. http://hdl.handle.net/1969.1/6012.
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Hypervariable, nuclear-encoded microsatellites were used to (i) estimate genetic
effective size (Ne) of red drum spawning over a two-week period in nine brood tanks at a
TPWD hatchery; (ii) estimate heritability of early-larval growth and of growth rate and
cold tolerance of juveniles; and (iii) test Mendelian segregation and independent
assortment of 31 nuclear-encoded microsatellites. Assuming all tanks contributed
equally to an offspring population, the maximum (expected) and observed Ne over the
nine brood tanks was 43.2 and 27.0, respectively. The estimate of Ne based on
observed variation in family size was 19.4. Simulations indicated that over a limited
time period the simplest approach to maximizing Ne for a release population would be to
utilize equal numbers of progeny from each brood tank. A family (genetic) effect was
found to contribute significantly to the variance in early larval growth, juvenile growth
rate, and cold tolerance. Estimates of narrow-sense heritability for these three traits
were 0.07 +- 0.03, 0.52 +- 0.21 and 0.20 +- 0.10 (two growth intervals measured), and 0.30 +- 0.11, respectively, under the genetic models employed. The relatively low estimate
of heritability for early larval growth suggests that genetic improvement for this trait
likely would be slow. The heritability estimates for juvenile growth rate and cold
tolerance, alternatively, suggest that genetic selection for these traits could be effective. Segregation at all 31 microsatellites fit Mendelian expectations for autosomal loci; a null
allele was inferred at two of the microsatellites. Results from pairwise tests of
independent assortment demonstrated that 20 of the 31 microsatellites could be placed
into seven linkage groups. Additional linkage groups inferred from a prior study
increased the number of inferred linkage groups in red drum to nine, with a range of two - five (avg. = 2.78) microsatellites in each linkage group. The remaining 11
microsatellites tested in this study assorted independently from all other microsatellites,
suggesting the possibility of 11 additional linkage groups.
12
Dickens, Hazel. "Thermal preferences of two cohorts of juvenile silver kob, Argyrosomus inodorus (Pisces: Sciaenidae)." Master's thesis, University of Cape Town, 2007. http://hdl.handle.net/11427/7489.
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Includes bibliographical references (leaves 27-29).The silver kob, Argyrosomus inodorus, has been identified as a viable species for mariculture in South Africa due to its high demand and market value as well as the necessary biological traits such as high fecundity and fast growth rates. In order for the full scale commercial production to become a reality however, it is important that the environmental conditions required for optimum growth at each phase of the species development are fully understood. Until recently, this sciaenid species was misidentified along with the dusky kob, Argyrosomus japonicus, as Argyrosomus hololepidotus, a fact that resulted in a poor understanding of the life history characteristics of the species and therefore the implementation of a poor management plan. As a result, wild stocks have been heavily over-exploited with spawner biomass-per-recruit ratios estimated at 2.9-12.5% of the pristine level. This study hypothesized that juvenile silver kob would exhibit a preferred temperature when a choice was available to them, and that this preferred temperature might change with age. Two cohorts of juvenile silver kob were acclimatized at 18°C and then subjected to identical temperature preference trials using temperature gradient tanks where the temperature ranged between 16 and 21.5°C as well as to identical isothermal control trials where the temperature throughout the tanks was 18°C. Salinity was kept constant at 35ppt and photoperiod remained 12L: 120 throughout. After a day of acclimation, observations were done over a five day period until the distribution of fish within the tanks had stabilized and that final temperature preferendum could be determined. During this time, dissolved oxygen concentrations were measured continuously to ensure that oxygen did not become limiting but remained above 6.4ppt. Results showed that the juveniles did indeed exhibit a preferred temperature with a range of 16.3 to 17.6°C for the first cohorts, and 16.9 to 18.1°C for the second. This difference between the preferred temperature ranges of the two age classes was found to be significant (p<0.01) by a Mann Whitney U Test. Kolmogorov-Smirnov tests showed no significant difference (p<0.01) between the tanks of the isothermal control trials indicating that there was no shoaling behaviour or individual tank bias affecting the results.
13
Childs, Amber-Robyn. "Estuarine-dependency and multiple habitat use by dusky kob Argyrosomus Japonicus (Pisces: Sciaenidae)." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1020241.
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Dusky kob Argyrosomus japonicus is a wide-ranging estuarine-dependent Sciaenid and an important fishery species throughout most of its distribution. It is one of South Africa’s most valuable coastal fishery species. High levels of juvenile exploitation in estuaries and ineffective management regulations have led to stock collapse, highlighting the need to better understand the spatial and temporal aspects of estuarine-dependency and multiple habitat use. Habitat connectivity is a critical property of estuarine-associated fishes and it therefore follows that knowledge of this link is fundamental in understanding population dynamics and the nursery role of estuarine and/or marine habitats. While dusky kob occur in both estuaries and nearshore coastal zones, limited information on connectivity among these habitats exists. The aim of this study is to assess the role of estuarine nursery habitats in the life cycle of the dusky kob by examining multiple habitat connectivity and determining the drivers associated with estuarine use. A total of 96 dusky kob (237–1280 mm total length) were tagged with acoustic transmitters in both the estuarine and marine environments of Algoa Bay, Eastern Cape, South Africa between May 2008 and September 2010. Their movements were monitored using a network of automated data-logging acoustic receivers deployed in the Sundays Estuary, seven neighbouring estuarine habitats, two commercial harbours and various sites within Algoa Bay. And more...
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Nakayama, Cintia Labussière. "Reprodução induzida e criopreservação do sêmen de papa-terra Menticirrhus Americanus (Perciformes: Sciaenidae)." reponame:Repositório Institucional da FURG, 2011. http://repositorio.furg.br/handle/1/2201.
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Tese(doutorado)-Universidade Federal do Rio Grande, Programa de Pós-Graduação em Aqüicultura, Instituto de Oceanografia, 2011.Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2012-07-22T21:32:30Z No. of bitstreams: 1 tese cintianakayama-1 em pdf.pdf: 1382153 bytes, checksum: 4984a9c31021ad542ff91f640d116ce6 (MD5)
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O papa-terra Menticirrhus americanus é um Sciaenidae com ampla distribuição na costa oeste do Atlântico, da Argentina aos E.U.A. Frente a seu potencial para aquicultura os objetivos do presente estudo foram a reprodução em cativeiro e a criopreservação do sêmen de M. americanus. Para a indução a maturação final e produção de ovos o estudo testou a efetividade da gonadotropina coriônica humana (hCG), acompanhando por meio da histologia os efeitos no desenvolvimento e a maturação dos ovócitos. Nos machos foi testada a qualidade espermática após resfriamento e criopreservação do sêmen em dimetil sulfóxido (DMSO). O desenvolvimento dos ovócitos foi classificado em pré-vitelogênese, vitelogênese e de maturação. No papa-terra o início da vitelogênese é marcado pela formação de glóbulos lipídicos e alvéolos corticais na periferia do ovoplasma. A vitelogênese protéica é caracterizada pela formação de grânulos de vitelo e coalescência dos glóbulos de lipídios. A coalescência do vitelo formando uma massa única, concomitantemente a hidratação dos ovócitos marcam o final da maturação. Fêmeas induzidas (300 UI hCG.kg-1) apresentaram 60% de sucesso nas desovas, com período de latência de 38,1 ± 3,4h. Os ovos mediram 730 ± 0,06 μm de diâmetro, com taxas de fertilização e eclosão de 63,8 ± 14,5 e 43,3 ± 10,7%, respectivamente. A fecundidade relativa foi estimada entre 40.080 e 294.000 ovos.kg-1. Em dosagens de 300, 600 e 900 UI de hCG.kg-1 o sucesso nas desovas foi de 45, 60 e 41 %, respectivamente. As três dosagens induziram a maturação final dos ovócitos, mas o melhor desempenho reprodutivo foi em 600 UI hCG.kg-1 com maior taxa de fertilização (73%) e maior produção estimada de larvas (39.000/desova). O sêmen apresentou osmolalidade de 370 mOsm.kg-1, espermatócrito de 88%, pH 6,9 e densidade de 9,9 x 109 espermatozóides.mL-1. A motilidade espermática foi ativada a partir de 300 mOsm.kg-1. Os testes de motilidade, após refrigeração (5˚C) foram realizados em intervalos de 3 h e demonstraram que o sêmen extrusado mantém a qualidade por 15 h, porém se mantido no testículo este período é de 6 h. Nos testes de criopreservação, as concentrações de DMSO 5, 10 e 20% não prejudicaram a motilidade espermática, nem a integridade de membrana pós-descongelamento, indicando DMSO 5% para a criopreservação do sêmen. Em suma, os resultados deste estudo permitiram delinear protocolos eficientes para maturação final dos ovócitos e criopreservação do sêmen, comprovando, pela primeira vez, a possibilidade da reprodução de Menticirrhus americanus em cativeiro. Ao mesmo tempo, os dados aqui apresentados deverão servir como base inicial para estudos futuros necessários a otimização da produção de larvas desta espécie.
The Menticirruhs americanus is a sciaenid widely distributed along the Atlantic west coast from Argentina to the USA. As potencial specie to aquculture the objectives of the present study were the reproduction in captivity and cryopreservation of M. americanus semen. To final oocyte maturation and egg production the study tested the human corionic gonadotropin (hCG) in different dosages, and its effects in final maturation with histological description of the oocytes development and events related. The spermatic quality test was used to evaluate the effectiveness for refrigerated storage and cryopreservation with dimethyl sulfoxide (DMSO). The oocytes development was classified as pre-vitellogenic, vitellogenic and in maturation. At the early lipid vitellogenesis is pronounced by lipid globules and cortical alveolus. Yolk vitellogenesis is characterized by appearance of yolk granule, lipid vesicles and yolk granules coalescence. The yolk coalescence became a unique yolk mass that resulting in hydration and at the end of the maturation. Females induced with hCG (300 IU .kg-1) presented spawning success in 60%, the latency period was 38.1 ± 3.4h. Eggs diameter was 730 ± 0.06 μm, fertilization and hatching rate were 63.8 ± 14.5% e 43.3 ± 10.7%, respectively. The relative fertility was estimated ranged from 40.080 to 294.000 eggs.kg-1 eggs.kg-1. The dosages 300, 600 and 900 IU hCG.kg-1 to the spawning success was 45, 60 and 41%, respectively. And all of these dosages were effectiveness in the final maturation, but the best reproductive performance, fertilization rate (73%) and larvae production (39,000/spawning), was found in 600 IU hCG.kg-1. Semen presented osmolality 370 mOsm.kg-1, spermatocrit 88%, pH 6.9 and density 9.9 x 109 spermatozoa.mL-1. Motility was activated from 300 mOsm.kg-1. The motility test after cold storage (5˚C), every 3 h, showed extrused semen retained motility for 15 and semen from testis for 6h. Semen cryopreserved with 5, 10 and 20% dimethyl sulphoxide (DMSO) post-thaw sustained the same spermatic quality and membrane integrity The results point to 5% DMSO to cryopreservation M. americanus semen. In conclusion, the results allowed to develop efficient protocols to induce of final maturation and semen cryopreservation, performing for the first time the viability of the M. americanus reproduction in captivity.
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Schmidt, Thassya Christina dos Santos. "Aspectos biológicos, com ênfase na reprodução das fêmeas, das principais espécies de Sciaenidae da Baía de Santos, costa central do Estado de São Paulo." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/21/21131/tde-01082011-132255/.
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O objetivo deste estudo foi descrever aspectos biológicos das espécies de cienídeos na baía de Santos. As coletas foram realizadas mensalmente, entre dezembro de 2004 e dezembro de 2005. Foram estudadas a composição específica; a estrutura populacional de dez espécies, incluindo idade e crescimento; a biologia reprodutiva de quatro espécies; e o tipo de fecundidade de Stellifer rastrifer. Foram capturados 29.306 exemplares pertencentes a 13 gêneros e 21 espécies, com S. rastrifer representando 70,4 % da composição total, seguido por Isopisthus parvipinnis e Stellifer brasiliensis, perfazendo 85%. A baía de Santos é caracterizada principalmente por indivíduos jovens, com a entrada de indivíduos para as populações ocorrendo em diversas épocas do ano. As análises reprodutivas e a confirmação histológica da maturação indicaram que as quatro principais espécies estudadas completam ciclo reprodutivo na região. As análises histológicas indicaram erros na identificação dos estádios macroscópicos dos ovários: fêmeas classificadas como \"em maturação\" (estádio B) foram reclassificadas como \"em reorganização\" após as análises microscópicas. Isopisthus parvipinnis e Stellifer brasiliensis apresentaram fêmeas desovantes nos meses de verão e Paralonchurus brasiliensis no inverno. A espécie Stellifer rastrifer apresentou distribuição de diâmetro dos ovócitos de maneira contínua, indicando que a espécie apresenta desenvolvimento assincrônico e fecundidade indeterminada.The goal of this study was to describe the biological aspects of Sciaenid species in Santos bay. Samplings were performed monthly, between November/2004 to December/2005. The specific composition; the population structures of ten species, including the age and growth; the reproductive biology of four species and the type of fecundity of Stellifer rastrifer were studied. In the present study 29,306 individuals were caught, belonging to 13 genus and 21 species, with the specie Stellifer rastrifer represented 70.4%, followed by Isopisthus parvipinnis and S. brasiliensis, resulting in 85% of the total Sciaenid composition. The Santos bay is mainly characterized by juveniles, with the recruitment of new individuals to the population occurring in several periods of the year. The reproductive analysis and the histological confirmation of the maturation stages indicated which the four main species studied complete their reproductive cycle in this region. The histological analysis indicated some errors in the identification of the macroscopic ovary stages, i.e., females classified as \"in maturation\" (stage B) were reclassified as \"in reorganization\" after the microscopic analysis. Hydrated females of Isopisthus parvipinnis and Stellifer brasiliensis occurred during the summer months while the hydrated females of Paralonchurus brasiliensis in the winter. The specie Stellifer rastrifer showed the oocytes diameter distribution in continuous pattern, indicating that the species has asynchronous development and indeterminate fecundity.
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Smith, Michael Edward. "Causes and consequences of individual growth rate variability in red drum (Sciaenops ocellatus) larvae /." Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3055247.
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Brooks, Hugh Anthony. "Energy utilization model for silver perch, Bairdiella chrysoura (bioenergetics, sciaenidae, growth, eelgrass, Chesapeake Bay)." W&M ScholarWorks, 1985. https://scholarworks.wm.edu/etd/1539616583.
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An energetics model was constructed as an alternative method to length frequency analysis for the estimation of growth for juvenile silver perch, Bairdiella chrysoura. The model approach was adopted since estimation of juvenile estuarine fish growth by only collecting length or weight frequency data is difficult due to the large bodies of water and variety of microhabitats that must be regularly sampled over short time intervals. Field and laboratory data was included in analysis of model compartments for growth, metabolism, food intake and energy loss in waste products. Food habit studies indicated that silver perch is a planktivore that feeds on calanoid copepods during the day and mysids at night. Estimated energy utilization for silver perch at maintenance and maximum rations were similar to literature values for yellow perch, Perca flavescens, and brown trout, Salmo trutta. Model simulation of growth for silver perch in the York River, Virginia from July through October 1981, contained less variation in the size prediction than growth rates determined by length frequency analysis. The model did not contain periods of negative growth as did the field data. By the end of the season, model predictions of silver perch length matched the average length of silver perch captured in the lower York River. The construction of energy utilization models through complementary laboratory and field research has been demonstrated to be a viable method for estimating growth for juvenile fishes. Length frequency analysis is limited to only expressing growth over time. The advantages of an energetics model are that it also defines trophic and ecological interactions as well as environmental factors that impact growth.
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Woolley, Lindsey. "The development of a practical diet for juvenile dusky kob, Argyrosomus japonicus, for the South African mariculture industry." Thesis, Rhodes University, 2009. http://eprints.ru.ac.za/1568/.
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Tuuli, Cynthia Darta. "The croaker fishery and dried swimbladder trade in Hong Kong, and the reproductive biology of the greyfin croaker, Pennahia Anea." Thesis, Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B43778367.
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Collett, Paul David. "Toward the development of a rearing protocol for juvenile dusky kob, Argyrosomus japonicus (Pisces: Sciaenidae)." Thesis, Rhodes University, 2008. http://hdl.handle.net/10962/d1005171.
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The South African mariculture industry is developing the rearing technology of indigenous fish species. Dusky kob (Argyrosomus japonicus) has high-quality flesh and a good market demand. Research is needed to determine the environmental requirements under which growth of dusky kob is optimised. This study assessed the effect of temperature, light intensity, feeding frequency and stocking density, respectively, on growth, feed conversion ratio (FCR) and survival of juvenile dusky kob within a weight range of 10-60 g fish⁻¹) in a series of four growth trials. The effect of temperature on growth and FCR was assessed at 14 temperatures from 17 to 28°C. The temperature for best growth was estimated to be 25.3 °C, while 21.4 °C was the temperature at which the best FCR was achieved. A growth trial testing the effect of light intensity on growth showed that light intensity did not affect growth in the range of 23 – 315 lx. Fish fed a restricted ration of 3.6% body weight per day (chapter 2) or 3.41% body weight per day (chapter 4) had a better FCR than fish fed to satiation. A trial to assess the effect of feeding frequency on growth and FCR showed that fish fed both two or three times daily grew better than those fed once daily. FCR was best in fish that were fed once or twice daily. Preliminary analysis of the results from a stocking density trial showed that stocking density in the range of 10 – 50 kg m⁻³ did not affect growth of juvenile dusky kob. It is recommended to culture dusky kob at a temperature of 25.3 - 21.4 °C at stocking densities up 50 kg m⁻³ to maximise growth. However, a study is needed to determine the environmental conditions needed to maximise profit under commercial conditions. The results allow the South African industry the opportunity to assess the culture potential of this species. In addition, the results will help develop protocols that can be used in other South African candidate aquaculture species such as silver kob, yellowtail, white-stumpnose and sole.
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Accioly, Ingrid Vilar. "Levantamento cariot?pico em esp?cies de peixes marinhos costeiros de fundo arenoso (Osteichthypes, Perciformes)." Universidade Federal do Rio Grande do Norte, 2007. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16774.
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Previous issue date: 2007-02-27Cytogenetics analyses in fish are important because they compose a private group among the vertebrates, occupying a central position in the animal evolution. The Perciforms Order, dominant in the marine and freshwater environment, it constitutes a model potentially useful in the genetic evaluation of populations, as well as in the understanding of its evolutionary processes. In spite of this, cytogenetics studies in this great group is scarce, above all for the inhabitants of sandy bottom and pelagics habits. The present work proposed to contribute for the cytogenetic characterization of nine species of fish marine of sandy bottom of the coast of Rio Grande do Norte (Brazil), identifying the evolutionary patterns related to the karyotype in these species and the existence of filogenetics affinities between them and other Perciformes. The animals were collected in the beaches of the Redinha, Ponta Negra and B?zios (Coast of Rio Grande do Norte) and in Saint Peter and Saint Paul Archipelago. Later on they were submitted to the cytogenetics technical that consist of mitotic estimulation, obtaining of mitotics chromosomes, proceeded by techniques of conventional coloration (Giemsa) and chromosomic bands (Ag-RONs and C band). Diploid number and fundamental number equal to 48 were observed in most of the species: Menticirrhus americanus, Ophioscion punctatissimus, Pareques acuminatus (Sciaenidae); Chloroscombrus chrysurus (Carangidae); Echeneis sp. 2 (Echeneidae); Archosargus probatocephalus (Sparidae) and Orthopristis ruber (Haemulidae). Trachinotus goodei (NF=52) (Carangidae) and Echeneis sp. 1 (Echeneidae) (NF=54) presented variation in NF, staying constant a diploid number equal to 48. RONs was situated in pericentromeric position in whole the scianids, and in the species Echeneis sp. 2 (22? pair), O. ruber and A. probatocephalus (1? pair), coinciding with great heterocromatics blocks in M. americanus (1? pair), P. acuminatus (2? pairl) and O. ruber (1? pair). RONs was also located in the telomeric area of the short arm of the 5? and 11? acrocentrics pairs in T. goodei, 4? and 19? pairs of C. chrysurus, 1? pair (sm) of Echeneis sp. 1. The C band detected centromeric blocks in most of the chromosomes of the species of Sciaenidae, Carangidae and Echeneidae, with great blocks in A. probatocephalus (4? pair). Heterocromatic blocks in telomeric areas in submetacentrics of Echeneis sp. 1, and pericentromerics in M. americanus (1? and 8? pairs), O. punctatissimus (1? pair) and P. acuminatus (2? pair) were also observed. It is noticed a marked conservatism cromossomic in the species of the family Scianidae and Haemulidae in what says respect to the number of acrocentrics chromosomes and the location of RONs. Even so it is outstanding the presence of heterocromatinization events during the karyotypic evolution of this family. Already in the families Sparidae and Carangidae, the obtained results reaffirm examples of small variations structural resultants of inversion and translocation Robertsonian, as important mechanisms of diversification karyotipical, as well as a pattern numerical evolutionary conserved, also observed in representatives of Echeneidae of Atlantic in relation to Pacific. The presence of RONs multiple, observed in the species T. goodei and C. chrysurus seems to represent a character derived in the family Carangidae. The results for the species O. ruber and A. probatocephalus suggest the presence of possible geographical or climatic barriers among populations of NE of Brazil in relationship the one of the SE
An?lises citogen?ticas em peixes s?o importantes porque os mesmos comp?em um grupo particular entre os vertebrados, ocupando posi??o central na evolu??o animal. A Ordem Perciformes, dominante nos ambientes marinhos e dulc?colas, constitui um modelo potencialmente ?til na avalia??o gen?tica de popula??es, como tamb?m no entendimento de seus processos evolutivos. Apesar disto, ainda s?o escassos os estudos citogen?ticos neste grande grupo, sobretudo para os habitantes de fundo arenoso e h?bitos pel?gicos. O presente trabalho se prop?s a contribuir para a caracteriza??o citogen?tica de nove esp?cies de peixes marinhos litor?neos de fundo arenoso do litoral do Rio Grande do Norte (Brasil), identificando os padr?es evolutivos relacionados ao cari?tipo nestas esp?cies e a exist?ncia de afinidades filogen?ticas entre elas e outros Perciformes. Os animais foram coletados nas praias da Redinha, Ponta Negra e B?zios (Litoral do Rio Grande do Norte) e no Arquip?lago de S?o Pedro e S?o Paulo. Posteriormente foram submetidos ?s t?cnicas citogen?ticas que consistem em estimula??o mit?tica, obten??o de cromossomos mit?ticos, seguida por t?cnicas de colora??o convencional (Giemsa) e bandamentos cromoss?micos (Ag-RONs e bandamento C). N?mero dipl?ide e n?mero fundamental iguais a 48 foram observados na maioria das esp?cies: Menticirrhus americanus, Ophioscion punctatissimus, Pareques acuminatus (Sciaenidae); Chloroscombrus chrysurus (Carangidae); Echeneis sp. 2 (Echeneidae); Archosargus probatocephalus (Sparidae) e Orthopristis ruber (Haemulidae). Trachinotus goodei (NF=52) (Carangidae) e Echeneis sp. 1 (Echeneidae) (NF=54) apresentaram uma varia??o no NF, mantendo-se constante um n?mero dipl?ide igual a 48. As RONs estavam situadas em posi??o pericentrom?rica em todas os scian?deos, e nas esp?cies Echeneis sp. 2 (22? par), O. ruber e A. probatocephalus (1? par), coincidindo com grandes blocos heterocrom?ticos em M. americanus (1? par), P. acuminatus (2? par) e O. ruber (1? par). As RONs tamb?m foram localizadas na regi?o telom?rica do bra?o curto do 5? e 11? pares acroc?ntricos em T. goodei, 4? e 19? pares de C. chrysurus, 1? par (sm) de Echeneis sp. 1. O bandamento C detectou blocos centrom?ricos na maioria dos cromossomos das esp?cies de Sciaenidae, Carangidae e Echeneidae, com grandes blocos em A. probatocephalus (4? par). Blocos heterocrom?ticos em regi?es telom?ricas em submetac?ntricos de Echeneis sp. 1, e pericentrom?ricas em M. americanus (1? e 8? pares), O. punctatissimus (1? par) e P. acuminatus (2? par) tamb?m foram observados. Nota-se um marcante conservadorismo cromoss?mico nas esp?cies da fam?lia Scianidae e Haemulidae no que diz respeito ao n?mero de cromossomos acroc?ntricos e a localiza??o das RONs. Por?m ? destacada a presen?a de eventos de heterocromatiniza??o durante a evolu??o cariot?pica desta fam?lia. J? nas fam?lias Sparidae e Carangidae, os resultados obtidos reafirmam exemplos de pequenas varia??es estruturais resultantes de invers?es e transloca??es Robertsonianas, como principais mecanismos de diversifica??o cariot?pica, bem como um padr?o evolutivo mais conservado numericamente, tamb?m observado em representantes de Echeneidae do Atl?ntico em rela??o ao Pac?fico. A presen?a de RONs m?ltiplas, observadas nas esp?cies T. goodei e C. chrysurus parecem representar um car?ter derivado na fam?lia Carangidae. Os resultados para as esp?cies O. ruber e A. probatocephalus sugerem a presen?a de poss?veis barreiras geogr?ficas ou clim?ticas entre suas popula??es no NE do Brasil, quando comparada com a regi?o SE
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Brogan, Sunny. "Red drum (Sciaenops ocellatus) Habitat Use in an Urban System; Behavior of Reintroduced Fish in Bayou St. John, New Orleans." ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1185.
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Bayou St. John is a degraded water-body located within the City of New Orleans and is the focus of restoration efforts. I tested the ability of reintroduced red drum (Sciaenops ocellatus) to survive in this system and assessed their habitat use and behavior. I tracked 29 red drum fitted with external acoustic radio transmitters to determine if they could survive the degraded habitats and determine their general dispersion within the Bayou. All 29 tagged red drum exhibited post-stocking movement (i.e., survival) and occurred primarily in the northern section of the Bayou (nearest Lake Pontchartrain). To assess habitat use and behavior on a finer scale, a second group of 19 red drum were internally tagged with VEMCO transmitters and movements monitored by four remote receivers. These fish exhibited behavior similar to red drum in natural habitats. Monthly movements changed as temperatures changed but were not influenced by diurnal differences, salinity, or conductivity.
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Whiteman, Kasey. "Evaluation of fisheries by-catch and by-product meals in diets for red drum (Sciaenops ocellatus)." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/3277.
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By-catch and wastes from processed fish and shrimp constitute a sizeable portion of commercial fishery landings. This discarded material is potentially valuable, for its content of fish meals and other substances. Fish meals, in particular, are increasingly in short supply for the manufacture of animal feeds, including feeds for farmed fish. Therefore, in this study, various by-catch and by-product meals of marine origin were evaluated with red drum (Sciaenops ocellatus), a carnivorous fish species native to the Gulf of Mexico that has been cultured over the past two decades for stock enhancement as well as for food. Four different kinds of by-catch or by-product meals [shrimp by-catch meal, shrimp processing waste meal, red salmon (Oncorhynchus nerka) head meal, and Pacific whiting (Merluccius productus) meal] were substituted for Special Select menhaden fish meal at two different levels (33% or 67% of crude protein) in prepared diets for red drum. Another treatment consisted of shrimp processing waste meal formulated on a digestible-protein basis to replace 33% of the protein from menhaden fish meal. Levels of calcium carbonate were reduced in two additional diets containing Pacific whiting, to evaluate the effects of ash content. Diets were formulated to contain 40% crude protein, 12% lipid, and 3.5 kcal digestible energy/g. Each diet was fed to triplicate groups of juvenile red drum in 38-l aquaria containing brackish water (7 ± 1 ppt) in two separate 6-week feeding trials. Survival, weight gain, feed efficiency, protein efficiency ratio and body composition responses were measured in each trial. Fish fed the by-catch meal at either level of substitution performed as well as fish fed the control diet containing protein solely from menhaden fish meal; whereas, fish fed the shrimp processing waste meal diets did significantly (P ≤ 0.05) worse than the controls, even when fed a diet formulated to be equivalent on a digestible-protein basis. Fish fed the red salmon head meal diet fared poorly, probably owing to an excessive amount of lipid in the diet that tended to become rancid. Overall, by-catch meal associated with shrimp trawling appears to be a very suitable protein feedstuff for red drum.
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Erasmus, Bernard. "Effects of CO2-induced ocean acidification on the early development, growth, survival and skeletogenesis of the estuarine-dependant sciaenid Argyrosomus japonicus." Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/60585.
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Although it is increasingly accepted that ocean acidification poses a considerable threat to marine organisms, little is known about the likely response of fishes to this phenomenon. While initial research concluded that adult fishes may be tolerant to changes predicted in the next 300 years, the response of early life stages to end-of-century CO2 levels (~ 1100 µatm according to the IPCC RCP 8.5) remains unclear. To date, literature on the early growth and survival of fishes has yielded conflicting results, suggesting that vulnerability may be species dependant. The paucity of ocean acidification research on fishes is particularly evident when one considers larval skeletogenesis, with no robust studies on its impacts on bone and cartilage development. This study addresses the early life embryogenesis, hatching success, growth, skeletogenesis and survival of an estuarine-dependant species. Dusky kob (Argyrosomus japonicus) were reared in a control (pCO2 = 327.50 ± 80.07 qatm at pH 8.15), intermediate (pCO2 477.40 ± 59.46 qatm at pH 8.03) and high pCO2 treatment (pCO2 910.20 ± 136.45 qatm at pH 7.78) from egg to 29 days post-hatch (dph). Sixty individuals from each treatment were sacrificed at the egg stage and at 2, 6, 13, 18, 21 and 26 dph, measured and stained using an acid-free double- staining solution to prevent the deterioration of calcified matrices in fragile larval skeletons. The proportion of bone and cartilage was quantified at each stage using a novel pixel-counting method. Growth and skeletal development were identical between treatments until the onset of metamorphosis (21 dph). However, from the metamorphosis stage, the growth and skeletal development rate was significantly faster in the intermediate treatment and significantly slower in the high treatment when compared to the control treatment. By 26 dph, A. japonicus reared in high pCO2 were, on average, 47.2% smaller than the control treatment, and the relative proportion of bone in the body was 45.3% lower in the high pCO2 treatment when compared with the control. In addition, none of the fish in the high pCO2 treatment survived after 26 dph. It appears that the combination of the increased energy requirements during metamorphosis and the increased energy cost associated with acid-base regulation may account for reduced growth, skeletogenesis and poor survival in high pCO2. Regardless of the driver, the results of this study suggest that the pCO2 levels predicted for the end of the century may have negative effects on the growth, skeletal development, and survival during metamorphosis.
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Walters, Sarah Lyle. "Mapping Tampa Bay Cynoscion nebulosus Spawning Habitat Using Passive Acoustic Surveys." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001318.
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Monteiro, Herbert Silva. "Análise quali-quantitativa dos Sciaenidae na pesca do camarão sete-barbas (Xiphopenaeus kroyeri), litoral de Santa Catarina Brasil." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/1830.
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Previous issue date: 2014-06-04Trawling with network-of-doors practiced by the artisanal fleet directed to-bobshrimp Xiphopenaeus kroyeri in central and northern coast of Santa Catarina is an efficient way to capture the target species. However, it has low selectivity and incidentally capture large contingent of demersal and benthic fauna, grouped on the designation of bycatch species, part of this is compounded by the Sciaenidae comprising teleost fish with great commercial importance. Based on this finding, the aim of this work was to evaluate qualitative and quantitative fish species present in the Sciaenidae accompanying fauna in three traditional areas of fishing-bob-shrimp. Seasonally, during the day, from September 2009 to July 2010, drags on traditional shrimp fishing areas in the municipalities of Bal. Barra South and Porto Belo, Santa Catarina, and monthly hauls were performed during the period September 2011 to August 2012 at easel Itapocoroy Penha, Santa Catarina. It appears that the composition of the Sciaenidae of accompanying fauna is dominated by demersal fish, belonging to two genera and three species Stellifer rastrifer, and S. brasiliensis Paralonchurus brasiliensis characterized dominant. The populations show seasonal fluctuations in abundance, with the highest catch rates in summer and lowest in winter. In general, the populations of the three species showed similar results in the evaluated parameters, experiencing a dominance of males in relation to females throughout the sampling period, with a predominance of males in the smaller length classes and the larger female. As the size of the first maturation of these species of approximately 9cm with the occurrence of two clutches per year. Trawling with network-of-doors practiced by the artisanal fleet operates intensely on juvenile population despite large share of the adult population.
A pesca de arrasto com rede-de-portas praticada pela frota artesanal dirigida ao camarão sete-barbas Xiphopenaeus kroyeri no litoral Centro-Norte catarinense é considerada eficiente na captura da espécie-alvo. Entretanto, apresenta baixa seletividade e incidentalmente captura grande contingente da fauna demersal e bentônica, agrupados sobre a denominação de fauna acompanhante, parte desta é composta pela família Sciaenidae que compreende peixes teleósteos com grande importância comercial. Tendo por base essa constatação, objetivou-se no presente trabalho avaliar qualiquantitativamente as espécies de peixes da família Sciaenidae presentes na fauna acompanhante em três áreas tradicionais de pesca de camarão setebarbas. Sazonalmente, durante o dia, de setembro de 2009 a julho de 2010, foram realizados arrastos em áreas tradicionais de pesca de camarões nos municípios de Bal. Barra do Sul e Porto Belo, em Santa Catarina, e arrastos mensais durante o período de setembro de 2011 a agosto de 2012 na Armação do Itapocoroy, Penha, Santa Catarina. Constata-se que a composição da família Sciaenidae da fauna acompanhante é dominada por peixes demersais, pertencentes a dois gêneros e a três espécies Stellifer rastrifer, S. brasiliensis e Paralonchurus brasiliensis que se caracterizam dominantes. As populações apresentam flutuações sazonais na abundância, com as maiores taxas de capturas no verão e as menores no inverno. De modo geral, as populações das três espécies apresentaram resultados semelhantes nos parâmetros avaliados, ocorrendo uma dominância dos machos em relação as fêmeas ao longo do período de amostragem, com o predomínio dos machos nas menores classes de comprimento e das fêmea nas maiores. Sendo o tamanho da primeira maturação dessas espécies de aproximadamente 9cm, com a ocorrência de duas desovas por ano. A pesca de arrasto com rede-de-portas praticada pela frota artesanal atua de forma intensa sobre a população juvenil apesar de grande participação da população adulta.
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Martin, Cassie R. "Intracohort variation in vital rates of age-0 red drum (Sciaenops ocellatus) testing for demographic restructuring during winter /." View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-1/martinc/cassiemartin.pdf.
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com, bryn_farmer@hotmail, and Bryn Farmer. "Comparisons of the biological and genetic characteristics of the Mulloway Argyrosomus japonicus (Sciaenidae) in different regions of Western Australia." Murdoch University, 2008. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20090716.94528.
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The research conducted for this thesis has produced quantitative data on the biology and population genetic structure of the Mulloway Argyrosomus japonicus in Western Australia, where this sciaenid is recreationally and commercially fished. These data were used 1) to test various hypotheses regarding the relationship between key biological characteristics of A. japonicus and both latitude and environmental variables, 2) to investigate the population structure and genetic characteristics of populations of A. japonicus on the west and south coasts of Western Australia and to assess the relationships between these populations and those of A. japonicus in eastern Australia and South Africa, and 3) to consider the implications of the biological and genetic results for management.
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Mojica, Alfredo Leandro Borie. "Aspectos reprodutivos de plagioscion squamosissimus (teleostei, sciaenidae) mantidos em tanque rede na comunidade do Lago do Catalão, Amazônia Central." Universidade Federal do Amazonas, 2011. http://tede.ufam.edu.br/handle/tede/4822.
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Plagioscion squamosissimus kept in cages did not complete the final maturation of oocytes, having to be induced to make the process happen. The reproductive inducers used were gonadotropin-releasing hormone (GnRH - Ovaprim ®) and human chorionic gonadotropin (hCG). In females, it was observed that the yolk globules and oil droplets were present in the oocytes fusion process end after 12 hours of induction using 1.4 ml/kg body weight of Ovaprim®. With 300 IU of hCG/kg was observed the onset of melting at 12 h. The males didn’t show fully developed gonads in both experiments, and no significant difference between treatments was found. The gonads of males develop in sync with the sonic muscle and P. squamosissimus produces longer sounds when is ripe. The sounds or "calls" may indicate the state of maturity of males in the natural habitat that occurred during the dry season, which were detected "calls" of longer duration (0.404 ±0.191 sec.). Therefore, major number of pulses (20.7 ±9.7 pulses/call) than flood season (0.152 ±0.056 sec. and 8.4 ±0.8 pulses/called respectively).The sounds recorded in cages during the dry season had shorter duration than the sounds captured in the wild, perhaps indicating that individuals in cages are in a maturation process. The methods of cannulation used in females and the bioacoustics of males were effective for assessing the maturity of freshwater white Croaker. The passive acoustic method allows predict the time and place of spawning of this species and when males are ready to spawn.
Plagioscion squamosissimus quando criada em tanque-rede não completa a maturação final dos ovócitos, tendo que ser induzida para que o processo aconteça. Os indutores reprodutivos utilizados foram o hormônio liberador de gonadotrofinas (GnRH - Ovaprim®) e gonadotrofina coriônica humana (hCG). Nas fêmeas, foi observado que os glóbulos de vitelo e gotículas de óleo presentes nos ovócitos estavam em processo de fusão final após 12 horas da indução utilizando 1.4 ml de ovaprim/Kg de peso vivo. Com 300 UI de hCG/kg foi observado o inicio da fusão às 12 h. Os machos não apresentaram as gônadas completamente desenvolvidas em ambos os experimentos e não houve diferença significativa entre os tratamentos. As gônadas dos machos se desenvolvem em sincronia com o músculo sonoro e a pescada-branca produz sons mais longos quando madura. Os sons ou “chamados” podem indicar o estado de maturação dos machos, no habitat natural ocorreu no período da seca, onde foram detectados “chamados” de maior duração (0,404 ±0,191 seg.), por tanto, maior numero de pulsos (20,7 ±9,7 pulsos/chamado), quando comparado com ao período da cheia (0,152 ±0,056 seg. e 8.4 ±0.8 pulsos/chamado respectivamente). Os sons gravados dentro do tanque rede durante a seca tiveram menor duração que os sons captados no habitat natural no mesmo período, indicando que os indivíduos no tanque-rede se encontram em processo de maturação. Os métodos de canulação utilizado nas fêmeas e a bioacústica nos machos foram eficientes para avaliar a maturação da pescada-branca. O método acústico passivo permite inferir sobre o período e local de desova desta espécie e quando esta pronta para a desova.
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Farmer, Bryn. "Comparisons of the biological and genetic characteristics of the Mulloway Argyrosomus japonicus (Sciaenidae) in different regions of Western Australia." Thesis, Farmer, Bryn (2008) Comparisons of the biological and genetic characteristics of the Mulloway Argyrosomus japonicus (Sciaenidae) in different regions of Western Australia. PhD thesis, Murdoch University, 2008. https://researchrepository.murdoch.edu.au/id/eprint/682/.
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The research conducted for this thesis has produced quantitative data on the biology and population genetic structure of the Mulloway Argyrosomus japonicus in Western Australia, where this sciaenid is recreationally and commercially fished. These data were used 1) to test various hypotheses regarding the relationship between key biological characteristics of A. japonicus and both latitude and environmental variables, 2) to investigate the population structure and genetic characteristics of populations of A. japonicus on the west and south coasts of Western Australia and to assess the relationships between these populations and those of A. japonicus in eastern Australia and South Africa, and 3) to consider the implications of the biological and genetic results for management.
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Farmer, Bryn. "Comparisons of the biological and genetic characteristics of the Mulloway Argyrosomus japonicus (Sciaenidae) in different regions of Western Australia." Farmer, Bryn (2008) Comparisons of the biological and genetic characteristics of the Mulloway Argyrosomus japonicus (Sciaenidae) in different regions of Western Australia. PhD thesis, Murdoch University, 2008. http://researchrepository.murdoch.edu.au/682/.
Full textAbstract:
The research conducted for this thesis has produced quantitative data on the biology and population genetic structure of the Mulloway Argyrosomus japonicus in Western Australia, where this sciaenid is recreationally and commercially fished. These data were used 1) to test various hypotheses regarding the relationship between key biological characteristics of A. japonicus and both latitude and environmental variables, 2) to investigate the population structure and genetic characteristics of populations of A. japonicus on the west and south coasts of Western Australia and to assess the relationships between these populations and those of A. japonicus in eastern Australia and South Africa, and 3) to consider the implications of the biological and genetic results for management.
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Boutin, Brian P. "Tidal tributaries and nearshore areas as nursery habitat for juvenile sciaenid fishes and other estuarine nekton in Delaware Bay and the Delaware Coastal Bays." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 193 p, 2008. http://proquest.umi.com/pqdweb?did=1654489861&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Griffiths, Marc H. "Aspects of the biology and population dynamics of the geelbek Atractoscion aequidens (Cuvier) (Pisces: Sciaenidae) off the South African coast." Thesis, Rhodes University, 1988. http://hdl.handle.net/10962/d1001970.
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The geelbek Atractoscion aeguidens is an important commercial and recreational linefish species along the South African eastern seaboard . Aspects of its biology and population dynamics were investigated using data collected from various sampling sites along the South African east coast and from catch statistics obtained from both the Sea Fisheries Research Institute (Cape Town), and dealer records. The biological aspects studied included age and growth, reproduction and feeding. It was established that A. aeguidens is a fast growing species with a relatively late age at sexual maturity and a 1:1 sex ratio. Feeding studies revealed that it has become specialized to feed on small pelagic fish. The South African geelbek stock consists of three distinct age related sub-populations, each representing a particular phase in the life cycle. The sub-adults (1-4 yrs) occur in the South West Cape and feed predominantly on anchovy, Engraulis capensis, which they follow, moving inshore in summer and offshore in winter. The adults (5-9 yrs) undergo a seasonal inshore migration to Natal where they spawn in spring. The dynamics of this migration are strongly influenced by the annual movement of their principal prey viz. , Sardinops ocellatus, to that region. As a result the geelbek first arrive in Natal during mid winter. Evidence is also presented to suggest that a significant number of "adolescent " fish (4-5 yrs) undergo limited gonad maturation and a partial migration to at least as far as the South East Cape. Spawning appears to occur offshore. It is postulated that eggs and larvae are transported southwards by the peripheral waters of the Agulhas Current. After spawning the adults probably remain offshore and use the current to aid their return to the South and South West Cape, where they spend summer feeding on the Agulhas Bank. Juveniles (<1 yr) first appear in the South East Cape between January and March. They apparently use this region as a nursery area for almost a year before moving southwards to join the sub-adults in the South West Cape. In the South East Cape, the juveniles feed initially on mysids whereafter they switch to anchovies and pilchards. A preliminary stock assessment using yield per recruit and spawner biomass per recruit models, indicated that despite the current legislation the South African geelbek population is already overexploited. This is largely attributed to high rates of fishing mortality of the migratory adult population. Further management recommendations are therefore proposed. These include a size limit (660 mm FL), derived from an investigation of the interrelationship between natural mortality and somatic growth in a theoretical unexploited cohort, as well as a uniform bag limit for all user groups (5 fish per person per day)
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Babane, Siviwe Elvis. "Towards understanding the effect of size variation on the aggressive and feeding behaviours ofjuvenile dusky kob Argyrosomus japonicus (Pisces: Sciaenidae)." Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/59592.
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Many studies have been conducted on the effect of size-grading in other fish species. However, there is a paucity of scientific information on the effects of size variation on cannibalism of juvenile dusky kob. Thus, a study focusing on the effect of size variation on juvenile dusky kob aggressive and feeding (browsing) behaviours was conducted. Three separate groups of hatchery-reared juvenile dusky kob of were obtained from Oceanwise (Pty) Ltd for use in a series of three experimental trials. In all trials, juvenile fish of the same age were size-graded and the COV-value was used to determine the size variation. The focal fish (largest fish) was exposed to groups of fish with different size variation for 30-min. behavioural observations before and after feeding in randomised trials. The first experimental trial (Chapter 2) quantified the effect of increasing size variation and observation time on the aggressive and browsing behaviours of juvenile dusky kob. On average, juvenile dusky kob weighed 3.60 ± 0.68 g fish-1 and measured 5.8 ± 0.41 mm. Each focal fish was observed (a) before feeding in the morning, (b) 2 h after feeding, (c) 6 h after feeding and (d) 12 h after feeding. Fish increased browsing behaviours (averaging 6.60 ± 0.56) and decreased intimidating aggressive behaviours (18.60 ± 1.39) 12 h after feeding. Other aggressive behaviours occurred but did not differ between observation times. Aggressive and browsing behaviours positively correlated with size variation variables, predominantly, 12 h after feeding. An average frequency of 19 chases were observed positively correlated with size variation, followed by average frequencies of 17 body bites and browses, and 11 tail bites per 30 min. Some behaviours including average frequencies of 0.2 chases, 4 tail bites, 2.4 intimidating and 0.3 browsing behaviours negatively correlated with the size variation, generally closer to the last meal. These preliminary observations thus showed that fish have become hungry approximately 6-12 h after feeding and substituted certain behaviours for others as time after feeding passed and as size variation increased. The second experimental trial (Chapter 3) consisted of the observations further testing the relationship between aggressive behaviours and size variation of juveniles of dusky kob averaging 0.43 ± 0.27 g fish-1. The focal fish was exposed to groups of fish of four size variation (COV) treatments for observations before and 12 h after feeding. Aggressive behaviours positively correlated with size variation both before and 12 h after feeding. An average frequency of 437 body bites positively correlated more often with COV, followed by average frequencies of 365 intimidating behaviours and 199 tail bites per 30 min., respectively, before and 12 h after feeding. The least often exhibited aggressive behaviours averaged 26 chases while positively correlating with size variation on the times specified. An average frequency of 311 intimidating behaviours before and after feeding including average of 28 tail bites after feeding negatively correlated with size variation. This may relate to shift of behaviours depending on the needs and capacity of the fish. Apparently, aggressive fish can change its behaviour as a function of COV-values rather than the mean size of the other fish. The third trial (Chapter 4) investigated the effect of the aggressor’s (focal fish) size in relation its aggressive and browsing behaviours to other fish (non-focal fish). Juvenile fish used for this trial, on average, weighed 30 ± 7.63 g fish-1. Aggressive and browsing behaviours were observed in four treatments of a) high COV and mean weight below, b) low COV and mean weight less, c) high COV and mean weight equivalent to and d) low COV and mean weight higher than that of the focal fish. Increased frequencies of aggressive and browsing behaviours per 30 min. occurred in treatment A, sharing similar frequencies in treatment C, compared to the other treatments (B and D) which shared certain frequencies. The intimidating behaviours predominated, followed by browsing, body bites, chases and tail bites, respectively. The results of the overall study suggest that the time passed after feeding and increasing size variation and differences facilitated aggressive and browsing behaviours in juvenile dusky kob. Dusky kob showed increasing aggressive behaviours as early as in the first two weeks after hatching, averaging 0.43 ± 0.27 g fish-1 with the frequency correlating with size differences. Consistent size-grading technique in the same-age fish should be used to manage size variation associated with aggressive behaviours. The period of about 4-6 h after feeding may explain the noticeable increased aggressive and browsing behaviours. Thus, fish should be fed immediately before or after evacuation of their guts to maintain less-aggressive behaviours of juvenile dusky kob. Fish generally increased aggressive and browsing acts before and long time after feeding than closer to after feeding. The study has provided the fundamental scientific groundwork for fish farmers and future researchers can further explore size variation, time after feeding and gut evacuation rate as critical components of aggressive behaviours. The scientific knowledge of aggressive and cannibalistic behaviours has essential application in farming management to achieve improved survival and growth rates in juvenile fish.
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Stewart, Christopher B. "Spatial and temporal variability in recruitment timing, relative abundance, and mortality of juvenile red drum (Sciaenpos ocellatus) in southeastern North Carolina /." Electronic version (PDF), 2006. http://dl.uncw.edu/etd/2006/stewartc/christopherstewart.pdf.
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Sabinson, Lia Mayrink. "Estrutura da ictiofauna e ecologia trófica de Sciaenidae acompanhante na pesca do camarão sete-barbas, no litoral de Santa Catarina, Brasil." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/1833.
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Previous issue date: 2014-06-13Financiadora de Estudos e Projetos
In trawling a significant portion of the captured fauna has no commercial value and is returned to the sea, causing biological and ecological changes, with impacts on the food chain, modifying processes of energy transfer in the ecosystem. Studies on the feeding habits of demersal fish provide basic information for understanding species trophic relations. Thus, this work aimed the undestandment of the feeding habits of the most abundant fish present in the bycatch of the Xiphopenaeus kroyeri artisanal fisheries of the coast of Santa Catarina, through the analysis of stomach contents, describing patterns of similarity, overlap and trophic structure. Sampling took place seasonally, from November 2009 to August 2010, in Balneario Barra do Sul, Porto Belo and Penha. Whaling vessels from the artisanal shrimping fleet were used for trawling. After sorting the specimens, they were frozen until the completion of biometrics and stomach content analysis. Information obtained through analysis of stomach contents were quantified via the Kawakami-Vazzoler feeding index, combining the frequency of occurrence and the relative volume of the items. Species of Sciaenidae family were the most abundant. Ctenosciaena gracilicirrhus, Cynoscion jamaicensis, Larimus breviceps, Menticirrhus americanus, Stellifer brasiliensis and S. rastrifer were classified as crab eaters, while Isopisthus parvipinnis crab eater/piscivore, Micropogonias furnieri as annelid eater/crab eater and Paralonchurus brasiliensis as annelid eater, however species were found to have very similar diets, altering the intake of certain items between seasons and locations. According Morisita overlap index, 9 cases of overlap were observed in Balneario Barra do Sul, 9 in Penha and 20 in Porto Belo. The bipartite foodwebs showed generality in the intake of food, with most species carrying multiple trophic interactions. Once the Sciaenidade family is the most abundant and diverse in the sea-bob-shrimp bycatch, iv its removal seems to directly influence the ecosystem processes in the region, with most species performing a wide range of interactions. Therefore their removal will gradually change the stability of benthic community.
Na pesca de arrasto uma parcela significativa da fauna capturada não possui valor comercial e é devolvida ao mar, provocando alterações biológicas e ecológicas, com impactos sobre a cadeia alimentar, modificando processos de transferência de energia no ecossistema. Estudos sobre os hábitos alimentares de peixes demersais fornecem informações básicas para a compreensão das relações tróficas das espécies. Assim, esteve trabalho teve a finalidade de conhecer o hábito alimentar das espécies mais abundantes na ictiofauna acompanhante na pesca do camarão sete-barbas Xiphopenaeus kroyeri no litoral de Santa Catarina, através da análise do conteúdo estomacal, descrevendo padrões de similaridade, sobreposição e estrutura trófica. As coletas foram realizadas sazonalmente, de novembro de 2009 a Agosto de 2010 em Balneário Barra do Sul, Penha e Porto Belo. Foram utilizadas embarcações do tipo Baleeira da frota artesanal de arrasto camaroeiro. Após a triagem os espécimes foram congelados até a realização da biometria e análise do conteúdo estomacal. As informações obtidas através da análise de conteúdo estomacal foram quantificadas através do índice alimentar de Kawakami e Vazzoler, combinando a freqüência de ocorrência e o volume relativo dos itens. Foi constatada a prevalência de espécies da família Sciaenidae. Ctenosciaena gracilicirrhus, Cynoscion jamaicensis, Larimus breviceps, Menticirrhus americanus, Stellifer brasiliensis e S. rastrifer apresentaram dieta carcinóafga, Isopisthus parvipinnis carcinófaga-ictiófaga, Micropogonias furnieri anelidófaga-carcinófaca e Paralonchurus brasiliensis dieta anelidófaga, porém de modo geral, as espécies possuem uma dieta alimentar muito semelhante, alterando a ingestão dos itens entre as estações do ano e local amostrado. De acordo com o índice de sobreposição de Morisita, foram constatadas 9 situações de sobreposição em Balneário Barra do Sul, 9 em Penha e 20 em Porto Belo. A rede ii bipartida mostrou a generalidade na ingestão de itens alimentares, com a maioria das espécies realizando múltiplas interações tróficas. A remoção dos Sciaenidae pela pesca de arrasto, direcionada ao camarão sete barbas, no litoral de Santa Catarina, parece influenciar diretamente os processos ecossistêmicos da região, uma vez que essa família, além de mais diversa e abundante na captura incidental, tem a maioria das espécies realizando uma vasta gama de interações. Sua remoção irá paulatinamente alterar a estabilidade da comunidade bentônica.
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CAMARGO-ZORRO, Mauricio. "Biologia e estrutura populacional das espécies da família sciaenidae (Pisces : Perciformes), no estuário do rio Caetê município de Bragança, Pará-Brasil." Universidade Federal do Pará, 1999. http://repositorio.ufpa.br/jspui/handle/2011/4145.
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CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
O presente estudo estima a biomassa média e caracteriza a distribuição espaço-temporal dos peixes da familia Sciaenidae no estuário do rio Caeté, no litoral norte do Brasil com ênfase nas espécies Stellifer rastrifer, Stellifer naso, Macrodon ancytodon e Cynoscion rnicrolepidotus. Estimam-se parâmetros biológicos como a idade da primeira maturação sexual (L50 ), os períodos de desova, a relação peso-comprimento, hábitos alimentares, a sobreposição das dietas, o consumo médio de alimento por unidade de peso (Q/B), bem como a estrutura e dinâmica populacional. Para tal durante o período outubro de 1996 a agosto de 1997, foram feitas 6 coletas bimensais, no estuário do rio Caeté. Onze espécies de peixes da família Sciaenidae foram coletadas. A biomassa média da família Sciaenidae foi de 0,840g/m². A distribuição espacial da biomassa no sistema foi relacionada com a dinâmica de recrutamento e reprodução das espécies. Assim, os juvenis das espécies S. rastrifer, S. naso e M. ancylodon distribuíram-se nas áreas mais internas do estuário e os adultos nas áreas externas, com maiores teores de salinidade. Os valores de L50 foram estimados em 10cm, 10,7cm e 21,5cm, respectivamente. Foram determinados para essas três espécies dois períodos anuais de reprodução, que definiram dois períodos de recrutamento, cada coorte apresentando diferentes parâmetros de crescimento. As relações peso-comprimento foram do tipo alométrico positivas, sem mostrar diferenças significativas entre sexos. Foi achada uma mudança na composição da dieta relacionada com o tamanho da espécie. Assim o zooplâncton foi comum nos indivíduos jovens, para ser substituído por juvenis de crustáceos decápodos, poliquetas e juvenis de peixes nos indivíduos maiores. O grau de sobreposição das dietas variou durante o desenvolvimento ontogénico das espécies. A relação Q/B mostrou que as espécies menores como S. rastrifer e S. naso consumem anualmente maior proporção de alimento em relação ao seu peso corporal, ao ser comparado com as espécies maiores M. ancylodon e C. rnicrolepidotus. Os resultados demostraram maiores taxas de crescimento, menores comprimentos para cada idade e menor longevidade para os peixes do estuário do Caeté, quando comparados com as mesmas espécies em latitudes maiores.
This study aimed to assess the average biomass and spatial and temporal distribution of the family Sciaenidae fishes in the estuary of the Caeté River, northern of Brazil, with special reference to the species Stellifer rastrifer, Stellifer naso, Macrodon ancylodon and Cynoscion microlepidotus. Age at first sexual maturity (L50 ), spawning season, the length-weight relationships, food diet, population consumption by biomass (Q/B), population structure and dynamics were estimated. 6 Bimonthly samples were taken in the estuarine area of the Caeté River, from October 1996 to August 1997. The average biomass of the family Sciaenidae was 0,840g/m². The spatial distribution in the system was related to spawning and recruitment. Juveniles of S. rastrifer, S. naso e M. ancylodon occurred inside some areas in the estuary, although larger individuals were abundant outside where salinity is higher. The L50 values were 10cm, 10,7cm e 21,5cm respectively. Two spawning periods in a year were found, which determine the recruitment of two cohorts, with different growth parameters. The length-weight relations were allometric and no differences were found by sex. An ontogenetic change was found in the diet composition of these species; young prey zooplancton and adults feed predominantly on larval stages of decapodes and poliquetes, and juveniles of fishes. Diet overlaps changed during the ontogenic development of each species. The relation Q/B indicated that S. rastrifer and S. naso consume more food in relation to the body size, in opposite to the larger species like M. ancylodon and C. microlepidotus. The fishes of the Caeté River presented higher growth and low longevity when compared to the same species inhabit the higher latitudes.
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Frese, Thomas Jay. "Acute toxicity of copper sulfate in juvenile red drum (Sciaenops ocellatus) and the establishment of safe methods to control parasitic disease." FIU Digital Commons, 1994. http://digitalcommons.fiu.edu/etd/3418.
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A series of static 96 hour acute toxicity tests were performed on juvenile red drum of different sizes. The tests were implemented to assess the acute toxicity of copper sulfate to juvenile red drum and establish narrowly defined guidelines for its usage in the treatment of Amyloodinium ocellatum and Cryptocaryon irritans. Median lethal concentrations at which a 50 percent mortality response (LC5 o) were observed ranged from 0.28 mg/1 to 0.88 mg/l in the series of five 96h static acute toxicity tests. A significantly higher sensitivity was observed in early juveniles (2.9 g, 53.3 mm) versus the test runs using older juveniles (11.9, 24.4, 24.7, and 34.4 g). Based on the results of acute toxicity tests and actual experimental treatment regimes performed throughout this study, administration of 0.4 mg/1 CuSO4 for 3h daily over a 14d duration is believed to be a relatively safe, yet effective dose for maturing juvenile red drum.
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Lagemann, Giovana Inês. "Biologia alimentar e reprodutiva de Pachyurus bonariensis Steindachner, 1879 (Perciformes, Sciaenidae) na fase pré-represamento do arroio Taquarembó, sul do Brasil." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/17313.
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O objetivo deste trabalho foi analisar a biologia alimentar e reprodutiva de Pachyurus bonariensis na fase pré-represamento do arroio Taquarembó, sul do Brasil. As coletas foram realizadas mensalmente de Julho de 2006 a Julho de 2007, com de redes de espera e picaré. A influência de fatores abióticos sobre a alimentação e reprodução foi analisada através dos testes não-paramétricos de Spearman e de regressões múltiplas. O período reprodutivo foi estimado através da variação da média mensal do índice gonadossomático (IGS) e da frequência dos estádios de maturação gonadal. Foram analisadas algumas gônadas de fêmeas e machos em vários níveis de desenvolvimento para descrever os aspectos morfológicos e histológicos dos estádios de maturação. Através da contagem dos ovócitos vitelinados foram estimadas as fecundidades absoluta e relativa. O tipo de desova foi determinado pela medida dos maiores diâmetros de 150 ovócitos retirados de gônadas em diferentes estádios de maturação e pela distribuição das médias dos IGS de cada estádio. Foram verificadas as proporções sexuais por período total de estudo e por classes de comprimento padrão para análise da estrutura populacional da espécie no local de estudo. Para a análise quali-quantitativa da dieta foram utilizados o índice de repleção estomacal (IR) e os métodos de composição percentual (CP), freqüência de ocorrência (FO), método gráfico de Costello e índice de importância alimentar (IIA). Para verificar o bem estar da espécie foi estimado o fator de condição mensal (FC). A variação dos fatores abióticos ao longo do período amostral não influenciou na alimentação dessa espécie, porém o fotoperíodo e a condutividade demonstraram ter relações significativas com o período reprodutivo que se estendeu de Outubro/2006 a Fevereiro/2007. O desenvolvimento ovocitário foi sincrônico em mais de dois grupos caracterizando uma desova do tipo parcelada. A fecundidade média absoluta foi de 39.313 ovócitos e a fecundidade relativa foi de 0,43 ovócito. O tamanho da primeira maturação foi estabelecido em 112,67 mm para as fêmeas e em 110,71 mm para os machos. A proporção sexual total foi de 1,2 fêmeas para 1 macho, apresentando diferenças significativas pelo teste do Qui-quadrado (α= 0.05) nos meses de setembro, outubro e dezembro de 2006 e as fêmeas alcançaram comprimentos maiores que os machos. A análise da dieta demonstrou que essa espécie possui hábito alimentar insetívoro aquático se alimentando principalmente de Diptera e Ephemeroptera. A comparação quali-quantitativa dos itens alimentares revelou que existem diferenças entre as dietas de jovens e adultos. Os valores do fator de condição mensal foram pouco influenciados pelo período reprodutivo. Através das análises de biologia alimentar e reprodutiva pode-se sugerir que essa espécie terá possibilidades de se adaptar às mudanças que serão causadas pelo represamento, pois a mesma tem preferência por ambientes lênticos, além de um hábito sedentário com alimentação insetívora aquática, fecundidade alta e desova parcelada, que favorecem uma boa adaptação em locais com tais como um reservatório.The aim of this paper was to analyze the feeding and reproductive biology of Pachyurus bonariensis before the damming in Taquarembó stream, south of Brazil. Samples were collected monthly from July 2006 to July 2007 by means of fishing nets of different mesh, sizes and one seine net. The influence of abiotic factors on the feeding and reproduction was analyzed through the non-parametric tests of Spearman and multiple regressions. Reproductive period was estimated by monthly variation of the mean gonadossomatic index (GSI) and by the frequency of gonadal maturation stages. Some female and male gonades in several development levels were histologically analyzed to describe morphological and histological aspects. Vitelline oocytes were counted from selected mature females to estimate the absolute and relative fecundity. The spawning type was determined by the measure of the largest possible diameters of 150 ovocytes whose samples were taken from gonades belonging to the different gonadal maturation stages. Data such as sex ratio and standard length classes were considered to populational structure character analysis of the species at the study site. The feeding habit was described through the repletion index (RI) and the analysis by the percentage composition (PC), the frequency of occurrence (FO), the Costello's graphic method and the feeding importance index (IIA). The condition factor (CF) was used to analyze the well-being of the species in the environment. The variation of abiotic factors during the sampling period did not influence the feeding of this species, but the photoperiod and conductivity demonstrated significant relationship with the reproduction period. The species presented a reproductive period that going from October/2006 to February/2007. The ovocitary development was synchronic in more than two groups, characterizing a parcelled spawning type. The absolute fecundity was of 39.313 ovocytes and the relative fecundity was 0,43 ovocytes. First maturation size estimated to males was 110,71 mm and to females 112,67 mm of standard length. Sex ratio tested by the Chi-square test (α= 0,05) was 1,2 females for 1 male, with significant differences in the months of September, October and December 2006. Females have larger standard lehgth than the males. The diet analysis showed that P. bonariensis had an insectivorous aquatic habit, feeding mainly of Diptera and Ephemeroptera. The qualitative-quantitative comparison of the feeding items showed differences between the diets of the young and the adults. The condition factor was little influenced by the reproduction period. Based on the analysis of the feeding and reproduction biology, one may suggest that this species will have great chances of adjusting to changes caused by the damming, once it showed a sedentary habit with insectivorous aquatic feeding, high fecundity and multiple spawning, which favor a good adaptation in places with such like the reservoir.
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Rossetti, Nani Adami. "The effect of dietary fish oil replacement with soybean oil on growth and health of dusky kob, Argyrosomus japonicus (Pisces: Sciaenidae)." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005116.
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Lipids are essential components for fish because they contain fatty acids that are vital for regular growth and health. Fish oil is rich in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are essential fatty acids for carnivorous fish, and therefore this product has traditionally been used as the main source of lipids in fish feeds. However, with declining fisheries resources worldwide and the rapid expansion of the aquaculture industry pressuring this finite resource, such ingredients are becoming less available and more expensive. It is therefore necessary to explore the utilization of ingredients that are sustainable and competitive alternatives to fish oil in marine finfish feeds. This work investigated the effects of the substitution of fish oil with soybean oil on the growth performance, feed efficiency, fatty acid composition of the liver tissue and some health parameters in juvenile dusky kob, Argyrosomus japonicus; an increasingly popular sciaenid marine aquaculture species in South Africa. Six diets (18 % total lipid and 46 % protein) with increasing percentage substitution of fish oil with soybean oil (1, 14, 28, 42, 56 and 70 %) were fed to juvenile kob. After 84 days of feeding these diets to the fish, no significant differences in fish length and weight between treatments were observed. However, there was a significant trend of a decrease in specific growth rate, ranging from (± standard error) 0.87 ± 0.06 to 0.72 ± 0.04 % body weight day⁻¹, and condition factor, ranging from 1.59 ± 0.03 to 1.54 ± 0.02, with increasing vegetable oil replacement in the diets between days 56 and 84. There were no differences in red blood cell count, haematocrit and haemoglobin concentration after 206 days of feeding. However, visceral fat index (VFI) increased significantly from 1.08 ± 0.17 % for fish fed diets with 28 % soybean oil, to 2.24 ± 0.15 % for fish fed diets with 70 % soybean oil. Similarly, hepatosomatic index (HSI) increased significantly from 0.84 ± 0.08 % to 1.80 ± 0.12 % in the control diet and the 56 % soybean oil diet, respectively. After 206 days of feeding, fish fed diets with 42 to 70 % soybean oil showed greater number of lipid vacuoles in the liver, which were also larger in size, and hepatocytes nuclei were displaced to the cell periphery. The fatty acid composition of the liver tissue strongly corresponded to the fatty acid composition of the diets. Linoleic acid accumulated in the liver of the fish fed increasing soybean oil in the diets. In contrast, EPA and DHA decreased from 13.63 to 1.97 %, and 14.34 to 3.28 %, respectively, in the liver tissue of fish fed diets with increasing soybean oil content; consequently the n-3/n-6 ratio was also significantly reduced with inclusion of vegetable oil in the diets. The trend of decreasing growth rate with increasing oil replacement towards the end of the trial corresponds with increases in VFI, HSI, as well as the fatty acid accumulation and lipid vacuoles in the liver. This suggests that dusky kob is less able to metabolise soybean oil at increased substitution levels which would account for the poorer growth at higher levels. The dependence of fish on dietary marine oil decreased significantly with each inclusion of soybean oil in the diets. Nonetheless, the calculations based on the nutrient ratio presented positive outcomes for all treatments, that is, values of marine oil dependency ratio were below one for all treatments. It is concluded that soybean oil can replace fish oil in formulated diets for dusky kob up to a level of 28 % of total dietary lipids, as evidenced by the good growth and feed efficiency, and no apparent negative health effects observed up to this level.
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Ventura, Eliana Cristina. "Biomarcadores bioquímicos em Orthopristis ruber (Cuvier, 1830) (Perciformes - Haemulidae) e Micropogonias furnieri (Desmarest, 1823) (Perciformes - Sciaenidae), coletados na costa sudeste brasileira." Florianópolis, SC, 2004. http://repositorio.ufsc.br/xmlui/handle/123456789/87321.
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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas. Programa de Pos-Graduação em Biotecnologia.Made available in DSpace on 2012-10-21T18:22:12Z (GMT). No. of bitstreams: 1 205423.pdf: 909840 bytes, checksum: caed38f919c6375ba37640963988843d (MD5)
A zona costeira brasileira possui vários ecossistemas extremamente produtivos, mas com grande sensibilidade e susceptibilidade à degradação ambiental. O aumento do aporte antrópico causado principalmente pela crescente concentração populacional e sistemas deficientes de tratamento de efluentes, tem impactado estes ambientes. Os contaminantes podem provocar uma série de distúrbios metabólicos aos organismos e causar uma diminuição dos estoques pesqueiros, da qualidade dos recursos vivos, podendo alterar a cadeia trófica dos oceanos. O Conselho Internacional para a Exploração do Mar (ICES) tem recomendado que programas de monitoramento do ambiente marinho passem a utilizar metodologias
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NEGRÃO, José Nazareno Cunha. "Avaliação da atividade gonadal de machos e fêmeas de pescada branca, Plagioscion squamosissimus (Heckel, 1840), (Pisces, Teleostei, Sciaenidae) no rio Pará (PA)." Universidade Federal do Pará, 2006. http://repositorio.ufpa.br/jspui/handle/2011/4449.
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Fêmeas e machos adultos de P. squamosissimus (Pisces, Teleostei, Sciaenidae) foram coletados mensalmente no Rio Pará, que banha a ilha do Capim (PA) (S 010 34. 971`; W 0480 52.932`), durante o período de fevereiro de 2004 a fevereiro de 2005, correspondendo ao total de 234 espécimes. As gônadas foram coletadas, fixadas e processadas de acordo com os métodos usuais utilizados para processamento em parafina e análise em microscopia de luz. A espécie em estudo é uma das principais fontes de proteína animal para a população local, sendo capturada de forma intensa e ininterrupta ao longo do ano. Com base em informações dos pescadores locais, essa captura parece estar determinando uma aparente diminuição quantitativa e qualitativa em seus estoques locais. A espécie apresenta desova parcelada e o desenvolvimento gonadal foi caracterizado nos estádios de repouso, maturação, maduro e esvaziado ou semi-esvaziado. Gônadas maduras foram encontradas nos meses de dezembro, janeiro e julho. A análise de correlação entre o estádio gonadal maduro e a variação temporal da relação gonadossomática (ΔRGS) indica também a ocorrência de desova nos respectivos meses. Não obstante, as informações obtidas da correlação entre a ΔRGS e a média de oócitos maduros e percentual de espermatozóides por túbulo seminífero, respectivamente, também indicaram haver desova nos respectivos meses, sendo que aparentemente a espécie apresenta uma desova mais intensa ou desova principal entre os meses de dezembro e janeiro (inverno), e outra desova menos intensa ou secundária no mês de julho (verão). Com base no método da morfologia tubular, foram determinados oito estádios do ciclo do epitélio seminífero (CES), sendo que no estádio 1 os túbulos seminíferos são compostos por espermatogônias primárias e cistos de spermatogônias secundárias; o estádio 2 é composto por espermatogônias primárias e secundárias e cistos de espermatócitos; estádio 3 é caracterizado por espermatogônias primárias, secundárias, cistos de espermatócitos e de espermátides jovens ou recém-formadas; estádio 4 com túbulos seminíferos caracterizados pela presença de espermatogônias primárias e secundárias, espermatócitos e por cistos de espermátides jovens e tardias; estádio 5 apresenta todas as células anteriores e é marcado pelo surgimento de espermatozóides no lúmen tubular; estádio 6 tem como características a diminuição dos cistos de células germinativas e considerável aumento do número de espermatozóides no lúmen tubular; os túbulos seminíferos no estádio 7 contêm poucos cistos de células germinativas e se inicia o esvaziamento da massa de espermatozóides do lúmen tubular; estádio 8 é o último do CES e é caracterizado pela aparente desorganização dos cistos remanescentes de células germinativas no túbulo seminífero.
Male and female adults of P. squamosissimus (Pisces, Teleostei, Sciaenidae) were collected monthly in the Para River that surrounds Capim insland, state of Para (S 010 34. 971` ; W 0480 52.932`), during the month of february 2004 to february 2005, having 234 specimes. The gonads were collected, mounted and processed in accordance with the standard methods of paraffin and analysis using a light microscope. The species under analysis is one of the principal sources of animal protein for the local population, fishing being uninterrupted and intensive throughout the year based on information given by local fisherman, the collection process appears to be determined by an apparent qualiquantitative reduction in local stock. The species represents spawn divisions, the gonad development was characterized in state of repose, maturation, mature and empty or half-empty. Mature gonads were found on the months of december, january and july. Correlation analysis between the maturing state of gonads, seasonal variations in relation to gonadosomatic indexes (GSI) and also the occurrence of spawn in the respective months. Nevertheless, the information obtained in correlation to GSI and mature oocyte mediums and between spermatozoa percentages by seminiferous tubule, respectively, also indicate spawning in the respective months, and apparently that the species represents a more intensive spawning period or a primary spawning period between the months of december and january, and a second or less intensive spawning period in the months of july. Based on the tubular morphology method, eight of the seminiferous epithelium cycle stages (SEC) were determined, stage 1 being seminiferous tubule that are comprised of primary spermatogonia and cysts of the secondary spermatogonia; stage 2 is comprised of primary and seconday spermatogonia and spermatocytes cysts; stage 3 is characterized by primary and secondary spermatogonias, spermatocyte cysts and young spermatids; stage 4 with seminiferous tubule characterized by presence of spermatogonias primary and secondary, spermatocyte and by presence of young and later spermatids cysts; stage 5 represents all of the previously mentioned cells and is highlighted by presence of spermatozoa in the tubule lumen; stage 6 is characterized by reduction of cysts of germinative cells and a considerable increase in number of spermatozoa in the tubular lumen; stage 7 is characterized by seminiferous tubule that contain few cysts of germinative cells and is marked by the begining of a mass emptying of spermatozoa of the tubule lume; stage 8 is the last of the SEC and is characterized by the apparent disorganization of the remaining germinative cellular cysts in the seminiferous tubule.
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Souza, Antonia Elissandra Freire de. "Respostas ecológicas de Plagioscion squamosissimus (Heckel, 1840) (Pisces, Sciaenidae) a uma seca supra sazonal como distúrbio em um reservatório do semiárido brasileiro." Universidade Federal Rural do Semi-Árido, 2016. http://bdtd.ufersa.edu.br:80/tede/handle/tede/586.
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The aim of this study was to evaluate the ecological responses of Plagioscion squamosissimus on a supra-seasonal drought as ecological disturbance. Fishes were caught in the reservoir of Santa Cruz River basin Apodi / Mossoró, using gill nets with meshes of different size from February 2010 to November 2014. It was evaluated by the abundance of Capture per in Effort Unit biomass (CPUEb) and number (CPUEn), and through a one-way ANOVA and Tukey's test evaluated temporal variation. Calculated the Pearson correlation coefficients between the abundance and the accumulated rainfall and reservoir volume. Study the stomach contents were used the frequency of occurrence and volumetric methods and feeding index (IAI). To evaluate the variation of the niche and individual expertise was used proportional similarity index (PSI), present in RInSp package statistical software R. The condition factor of individuals was dismissed from the parameters of length-weight relationship determined by the equation: Wt = a Lpb. To assess differences in condition factor we carried out a two-way ANOVA followed by a Tukey test. It was registered a decrease in abundance as the reservoir level was decreasing, which is positively correlated with the volume of the reservoir, but not accumulated precipitation. P. squamosissimus diet consisted of shrimp, gastropod, plant material, fish, insects and shrimp larvae. Among the categories of items, the shrimp had the highest contribution in terms of frequency of occurrence and in volumetric. In 2010, 2013 and 2014 was recorded a higher frequency GR 0 (42.79; 37.77; 38.97). The proportional similarity index (PSI) showed high similarity between diet two individuals and the population, and individual expertise in November 2014. The highest average condition factor was obtained in 2012 and in the months May, found significant differences both between years and between months. The dry season above negatively affect the species by reducing the habitat area leading to reduction of their abundance. It is believed that the volume reduction causes major predator encounter rates with prey and this leads to an individual specialization trend. These results support the view that the dry cause changes in organisms
O objetivo desse estudo foi avaliar as respostas ecológicas de Plagioscion squamosissimus frente uma seca supra sazonal como distúrbio ecológico. Os peixes foram capturados no reservatório de Santa Cruz, bacia do rio Apodi/Mossoró, utilizando redes de espera com malhas de diversos tamanho no período de fevereiro de 2010 a novembro de 2014. Foi avaliada a abundância através da Captura Por Unidade de Esforço em biomassa (CPUEb) e número (CPUEn), e por meio de uma ANOVA one-way e teste de Tukey avaliou-se sua variação temporal. Calculou-se os coeficientes de correlação de Pearson entre a abundância e a chuva acumulada e volume do reservatório. Para o estudo dos conteúdos estomacais foram utilizados os métodos de frequência de ocorrência e volumétrica e o índice alimentar (IAi). Para avaliar a variação do nicho e especialização individual foi utilizado o índice de similaridade proporcional (PSi), presentes no pacote RInSp do software estatístico R. a condição corporal dos indivíduos foi inferida por meio do fator de condição alométrico a partir dos parâmetros da relação peso-comprimento determinada pela equação: Wt = a Lpb. Para avaliar as diferenças no fator de condição foi realizada uma ANOVA two-way seguida por um teste de Tukey. Registrou-se uma redução na abundância à medida que o nível do reservatório foi diminuindo, sendo esta correlacionada positivamente com volume do reservatório, mas não com chuva acumulada. A dieta de Plagioscion squamosissimus foi composta por camarão, gastrópode, material vegetal, peixe, insetos e larva de camarão. Dentre as categorias de itens, o camarão apresentou a maior contribuição em termos de frequência de ocorrência. Em 2010, 2013 e 2014 foi registrado uma maior frequência GR 0 (42,79%; 37,77%; 38,97%). O índice de similaridade proporcional (PSi) mostrou elevada similaridade entre a dieta dos indivíduos e da população, e especialização individual em novembro de 2014. As maiores médias do fator de condição foi obtida em 2012 e entre os meses maio, sendo encontrada diferenças significativas tanto entre os anos, como entre os meses. A seca supra sazonal afetou negativamente a espécie através da diminuição da área de habitat levando a redução de sua abundância. Acredita-se que a redução do volume provoca maiores taxas de encontro do predador com a presa e isso leva a uma tendência de especialização individual. Os resultados dão suporte a visão de que as secas causam alterações nos organismos
2017-03-02
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Herzka, Sharon Zinah. "Characterization of the recruitment patterns of red drum (Sciaenops ocellatus) larvae to estuarine nursery habitat using stable isotopes as natural tracers of settlement /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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ALMEIDA, L. L. "Uso de Habitat e Recursos Alimentares Por Stellifer Brasiliensis (schultz, 1945) (perciformes, Sciaenidae) na Área de Proteção Ambiental de Conceição da Barra-es." Universidade Federal do Espírito Santo, 2018. http://repositorio.ufes.br/handle/10/9408.
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Previous issue date: 2018-02-20Este estudo visou descrever os hábitos alimentares e a utilização do habitat por Stellifer brasiliensis na Área de Proteção Ambiental (APA) de Conceição da Barra, Espírito Santo. Para tal, foi realizada a análise de conteúdo estomacal associada à análise de isótopos estáveis de carbono (δ13C) e nitrogênio (δ15N). Para se avaliar a utilização do habitat, foi avaliada a distribuição espaço-temporal da abundância, biomassa e comprimento total (CT, mm) da espécie. A ictiofauna foi amostrada mensalmente com redes de arrasto de fundo em quatro pontos distribuídos em um gradiente de salinidade. Para análise de abundância, biomassa e CT de juvenis e adultos, estas ocorreram entre maio/2014 e abril/2017; para a análise de conteúdo estomacal, entre julho/2015 e julho/2016; e para a análise de isótopos estáveis, peixes e presas foram coletados entre março/2016 e março/2017. As coletas de produtores primários ocorreram nos meses de abril, junho, agosto, setembro e dezembro/2016 e em junho/2017. A espécie apresentou maior abundância (F= 4,586, p<0,005) e biomassa (F= 7,139, p<0,005) no P4. Os maiores comprimentos foram registrados no inverno e outono no P1 e na primavera e verão no P4. Os itens alimentares de maior importância para a espécie foram Polychaeta, Thalassinidae e Penaeidae, para juvenis foram Penaeidae, Euphausiacea e Copepoda e para adultos foram Polychaeta, Thalassinidae e Copepoda. Os valores de δ13C de S. brasiliensis foram similares entre as estações, os pontos e as fases ontogenéticas e variaram de -17,45 ± 1,35 a -25,81 ± 0,67 nos juvenis e -18,28 ± 3,09 a -23,29 ± 1,37 nos adultos, enquanto as médias de δ15N variaram entre 12,73 ± 0,95 a 16,24 ± 0,32 nos juvenis e 13,83 ± 1,39 a 16,29 ± 0,68 nos adultos. As médias de δ15N indicaram que ambas as fases ocupam o mesmo nível trófico. As médias de δ13C nos juvenis e adultos no P1 foram similares aos valores de δ13C nos crustáceos Xyphopenaeus kroyeri e Alpheidae, indicando que estes são itens consumidos por ambas as fases ontogenéticas. Houve correlação negativa entre os valores de δ13C com o CT dos peixes, indicando que quando o peixe cresce, o valor de δ13C diminui, enquanto a correlação de δ15N foi positiva, indicando que quando o peixe cresce, o valor de δ15N aumenta. Palavras chave: Distribuição espacial, ecologia trófica, dieta, isótopos estáveis, bycatch
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Deary, Alison L. "Ontogeny of the feeding apparatus and sensory modalities: Relationship to habitat differentiation among early life history stage drums (Sciaenidae) in the Chesapeake Bay." W&M ScholarWorks, 2015. https://scholarworks.wm.edu/etd/1539616627.
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Although the form and function of the structure of the feeding apparatus and diet are linked in adult fishes, it is often not clear when during ontogeny the ecomorphological patterns enable early life history stage fishes (ELHS) to partition their foraging niches and reduce competition. Sciaenid (family Sciaenidae) species exhibit variability in the structure of the feeding apparatus, which allows them to exploit more foraging habitats as adults than any other family in the Chesapeake Bay. In this study, ELHS and juvenile sciaenids representing three foraging guilds (pelagic: n=92, 2.9-48.2 mm SL; generalist: n=71, 4.3-53.8 mm SL; and benthic: n=75, 1.9-43.2 mm SL) were captured during weekly, shore-based ichthyoplankton and trawl surveys throughout the lower Chesapeake Bay, York River, and tidal inlets on Eastern Shore of Virginia. Stomachs were removed, specimens were cleared and double stained, and elements of the feeding apparatus were measured. A smaller subset of specimens (n=17) were stained using a 1% phosphotungstic acid solution and then scanned using micro-computed tomography to determine sensory modality in ELHS sciaenids representing the same foraging guilds. A dietary shift occurred first in pelagic sciaenids (16 mm SL), which corresponded to an expansion of sensory modalities, particularly gustation and audition that augment vision. The dietary shift was observed next in benthic sciaenids at 20 mm SL, which corresponded to the acquisition of oral and pharyngeal specializations suited to exploiting benthic prey even though they lacked sensory specializations. Finally, generalist sciaenids experienced a dietary shift at 35 mm SL, which occurred after the expansion of sensory modality (particularly vision, olfaction, gustation, and mechanoreception) but before specializations to the feeding apparatus were observed. Phylogenetic signal, measured as Pagel's lambda, was also calculated for oral jaw elements using a molecular and a morphological topology to determine if evolutionary history may constrain the configuration of these elements and to understand how topology may influence the detected phylogenetic signal. Pagel's lambda was low for pelagic sciaenids in premaxilla, lower jaw, and ascending process length, regardless of the topology used in the analysis. The signal was variable for benthic sciaenids depending on the topology used in the analysis; the signal was low when a morphological topology was used but was high for lower jaw and ascending process length when a molecular topology was used. In benthic sciaenids, Pagel's lambda, was intermediate for premaxilla length when the molecular topology was used, suggesting that the length of the premaxilla is influenced by natural selection despite some phylogenetic constraints. Therefore, the morphological patterns detected in ELHS sciaenids are not constrained exclusively by evolutionary history and represent ecomorphological, which suggest that sciaenids are able to partition foraging in nursery habitats during these early stages.
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Daniel, Simon James. "Investigations into the nutritional requirements of juvenile dusky kob, Argyrosomus japonicus (Pisces sciaendae), under ambient culture conditions." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1002602.
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The effect of dietary protein, protein and energy ratios, fish meal replacement by Soya bean meal and feeding frequency was investigated on the growth, feed efficiency and body composition, of juvenile dusky kob, Argyrosomus japonicus. The effect of dietary protein levels was investigated by comparing isocaloric diets containing 35, 40, 45 and 55% protein. Dietary protein inclusion level significantly affected specific growth rates, feed efficiency and body composition (in terms of fat deposition) and results show that a minimum of 45% and maximum of 52.3% dietary protein is optimal. The protein and energy requirements were investigated by comparing three protein levels (35,40 and 45%) with three lipid levels (6, 9 and 12%) in a 3x3 factorial design. A diet 45% protein and 9% lipid, with a P: E ratio of29 mglkJ and DE of 15.5 kJ/g resulted in an optimal specific growth rate (1.6± 0.2), feed efficiency (FCR= 1.7±0.44; PER= 1.36) and body composition for A. japonicus. To investigate the effect of partial fish meal replacement by Soya bean meal (SBM) in the diet, 20-50% of the protein from fish meal was substituted by protein from SBM, and were compared with a control diet containing only fish meal. No significant differences in the specific growth rates, feed efficiencies and the body composition were recorded for the fish fed the control diet and for fish fed the 20 and 30% SBM treatments. Results show that up to 30% of the protein from fish meal can be replaced with protein from SBM in the diet of this species. The effect of feeding frequency and gut evacuation time was investigated by comparing four feeding frequencies. Fish were fed to satiation either once, twice, three or four times a day. Feed intake was significantly affected by feeding frequency and fish fed 2, 3 and 4 meals a day ate significantly more food (p< 0.05) than the fish fed one meal a day. No significant differences (p> 0.05) in the specific growth rates, feed efficiencies and body composition were recorded for fish fed 2, 3 and 4 times a day. Feed intake was used to calculate an optimal daily ration and feeding two meals a day resulted in an optimal daily ration of 4% BW/day. A gut evacuation time of 7.25 hours indicates that fish fed twice a day probably had sufficient time to digest their food and evacuate their guts, resulting in the same daily feed intake as fish given 3 and 4 meals a day. Results conclude that under the present experimental conditions, a minimum daily ration of 4% BW/day, fed twice a day (in the morning and evening) is required for optimal growth (SGR= 1.33± 0.1), feed efficiency (FCR= 1.96± 0.4; PER= 1.44± 0.2) and body composition in juvenile dusky kob.
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Locascio, James Vincent. "Passive Acoustic Studies of Estuarine Fish Populations of Southwest Florida." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1700.
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Recordings of fish sound production were made in Charlotte Harbor, Florida using Long Term Acoustic Recording Systems (LARS) programmed to record 10 seconds of sound every 10 minutes. Results demonstrated a strong circadian pattern in fish sound production that occurred within a few hours of dusk each evening. Sound production lasted on average 8.7 hrs each evening during the peak spawning season. LARS were deployed when Hurricane Charley crossed Charlotte Harbor in August, 2004. The hurricane did not inhibit nightly chorusing events of spawning fish. Rather, sound levels produced by spawning fish on the night of and 3 days after the hurricane were higher and lasted longer than any of the 9 days recorded prior to the hurricane.
Acoustic time series data recorded at multiple sites in Charlotte Harbor during 2005 revealed changes in the spatial distribution of fish sound production in response to increased freshwater inflow and consequent decreased bottom dissolved oxygen concentrations in early June. Fish sound production decreased rapidly over several days at study sites in the northern portion of the harbor most immediately affected by changes in environmental conditions. Meanwhile, fish sound production increased at the study site furthest seaward where normoxic levels were sustained. By August levels of fresh water inflow decreased substantially, bottom dissolved oxygen levels increased and sound production resumed at sites previously affected by these conditions. Fish sound production began intermittently in February and ended in November. Peak levels were reached by mid-late April / early May and continued throughout the summer time. Seasonal patterns of sound production match the reported spawning periods of estuarine sciaenid species recorded.
Black drum sound production was measured in the canal systems of Cape Coral and Punta Gorda, Florida during the 2004-2006 spawning seasons. The circadian pattern of sound production was similar to other sciaenids documented in Charlotte Harbor. Seasonal patterns of black drum sound production occurred during October through April and peaked in February. This seasonal period of sound production also matched patterns of black drum reproductive readiness and spawning reported in the literature for the Gulf of Mexico.
A hydrophone array was used in the Cape Coral canal system to localize calling black drum and measure source levels and propagation of calls. Source level estimates averaged 165 dBRMS re: 1muPa SPL (SD=1.0) (n = 1,025). Call energy was concentrated in the fundamental frequency (94 Hz) and first two harmonics (188 Hz and 282 Hz). A square root model best described propagation of the fundamental frequency and first harmonic and a log 10 model best described the second harmonic. Based on the mean RMS source level, signal propagation, background levels, and hearing sensitivity, the communication range of black drum at the study site was estimated at between 33 and 108 meters and was limited by background levels, not auditory sensitivity.
The timing and levels of sound production and egg production were compared in black drum. Eggs were collected hourly from 1800 - 0400 by surface plankton tows on two consecutive evenings while black drum sound production was continuously recorded. This sampling effort was conducted five separate times from January through April, 2006. Evidence of the time of spawning was indicated by the collection of blastodiscs (fertilized single cell eggs) or back calculated early cleavage stage eggs. Neither the timing nor the quantity of sound production was positively correlated with egg production on a nightly basis and the greatest densities of eggs were collected on evenings which had the lowest levels of sound production. This may have been due to differences in the fecundity of individual females spawning on the evenings when sampling was conducted.
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Rodrigues, Filho Jorge Luiz. "Bioecologia de espécies do gênero Stellifer (Pisces, Sciaenidae) acompanhantes na pesca artesanal do camarão sete-barbas, na Armação do Itapocoroy, Penha, Santa Catarina, Brasil." Universidade Federal de São Carlos, 2008. https://repositorio.ufscar.br/handle/ufscar/1937.
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Previous issue date: 2008-04-04Universidade Federal de Sao Carlos
The fishery of sea-bob-shrimp Xiphopenaeus kroyeri with over-trawl nets with doors used by artisanal fishery is considered an efficient method for the capture of the target specie along the Brazilian Cost. However, it presents a low selectivity and captures a high amount of the demersal and benthonic fauna that are know as accompanying fauna. Among these, is frequently found that they of the target species, the fish of the genus Stellifer. Therefore, this study, aimed to determine the bioecological characteristics of fishes of this captured in fishing held in the Armação Itapocoroy, Penha, Santa Catarina, in two ways: in the first chapter, analyzing the population structure and the reproductive aspects of the species Stellifer rastrifer, Stellifer stellifer e Stellifer brasiliensis exploited in in the period of from april/2006 to march/2007 and, in the second chapter, assessing the annual and monthly abundance distributions of the exploited Stellifer spp. populations during the years of 1996 2006.
A pesca de arrasto com redes-de-porta praticada pela frota artesanal, dirigida ao camarão sete-barbas Xiphopenaeus kroyeri no litoral brasileiro é considerada eficiente na captura da espécie-alvo. Entretanto, apresenta baixa seletividade e incidentalmente captura grande contingente da fauna demersal e bentônica, agrupados sobre a denominação de fauna acompanhante. Dentre esses, destacamse, devido ao fato de possuírem o mesmo habitat que a espécie-alvo, os peixes do gênero Stellifer. Tendo por base esta constatação objetivou-se, no presente trabalho, determinar as características bioecológicas de espécies do gênero Stellifer ocorrentes na pesca artesanal realizadas em Armação do Itapocoroy, Penha, Santa Catarina, abordando dois aspectos: no primeiro capitulo, analisando a estrutura das populações e os aspectos reprodutivos das espécies Stellifer rastrifer, Stellifer stellifer e Stellifer brasiliensis, capturadas no período de abril/2006 a março/2007 e, no segundo capitulo, avaliando as distribuições mensais e anuais da abundância das populações de Stellifer spp. capturadas durante os anos de 1996 a 2006.
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Sherwood, Edward T. "Post-release rate of loss and emigration of juvenile red drum (Sciaenops ocellatus) stocked out-of-season in the Chassahowitzka National Wildlife Refuge, Florida." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0000788.
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