Artykuły w czasopismach na temat „Larvae – Dispersal”
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1
Fobert, Emily K., Eric A. Treml i Stephen E. Swearer. "Dispersal and population connectivity are phenotype dependent in a marine metapopulation". Proceedings of the Royal Society B: Biological Sciences 286, nr 1909 (28.08.2019): 20191104. http://dx.doi.org/10.1098/rspb.2019.1104.
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Larval dispersal is a key process determining population connectivity, metapopulation dynamics, and community structure in benthic marine ecosystems, yet the biophysical complexity of dispersal is not well understood. In this study, we investigate the interaction between disperser phenotype and hydrodynamics on larval dispersal pathways, using a temperate reef fish species, Trachinops caudimaculatus . We assessed the influence of larval traits on depth distribution and dispersal outcomes by: (i) using 24-h depth-stratified ichthyoplankton sampling, (ii) quantifying individual phenotypes using larval growth histories extracted from the sagittal otoliths of individual larvae, and (iii) simulating potential dispersal outcomes based on the empirical distribution of larval phenotypes and an advanced biological-physical ocean model. We found T. caudimaculatus larvae were vertically stratified with respect to phenotype, with high-quality phenotypes found in the bottom two depth strata, and poor-quality phenotypes found primarily at the surface. Our model showed high- and average-quality larvae experienced significantly higher local retention (more than double) and self-recruitment, and travelled shorter distances relative to poor-quality larvae. As populations are only connected when dispersers survive long enough to reproduce, determining how larval phenotype influences dispersal outcomes will be important for improving our understanding of marine population connectivity and persistence.
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Afandy, Zulfikar, Ario Damar, Syamsul Bahri Agus i Budy Wiryawan. "CORAL LARVAL DISPERSAL MODEL ON CONSERVATION AREA OF KAPOPOSANG MARINE TOURISM PARK". Coastal and Ocean Journal (COJ) 1, nr 2 (7.11.2017): 39–51. http://dx.doi.org/10.29244/coj.1.2.39-51.
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The availability of information related to the pattern of connectivity between coral reef is one of the key in coral reef conservation management. The identification of pattern of connectivity in the form of dispersion dynamics of coral larvae is very important as the development of coral reef itself is highly depended upon the external input, which this input must be accordingly managed in order to support the continuity of coral larvae supply. This research’s objectives are including to create the coral larvae dispersal model of Marine Protected Area (MPA) of Kapoposang. For instance, the modelling of coral larvae dispersal had been conducted using the biophysics modelling which combined the biological and physics factor in order to obtain the recruitment scenario and the traces of larvae dispersal. This simulation used coral larvae object with the Pelagic Larval Duration (PLD) for 30 days, the larvae release was conducted during the full moon and during the west and east monsoon. The result of the larvae dispersion model has indicated that the coral larvae dispersion process was influenced by the currents and variation of monsoons. Based coral connectivity pattern on Kapoposang found site Gondongbali, Kapoposang2, Suranti and Pamanggangang as a source. Then other location as sink by received larvae from other site are Gondongbali, Kapoposang, Pamanggangang, Taka Karangkarangang, Taka Pallawangang and Taka Palekko.
Keywords
connectivity, coral reef, larva dispersal, marine protected area, twp kapoposang
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Lechner, Aaron, Hubert Keckeis, Elisabeth Schludermann, Franz Loisl, Paul Humphries, Martin Glas, Michael Tritthart i Helmut Habersack. "Shoreline configurations affect dispersal patterns of fish larvae in a large river". ICES Journal of Marine Science 71, nr 4 (7.09.2013): 930–42. http://dx.doi.org/10.1093/icesjms/fst139.
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Abstract The dispersal patterns of marked larvae of the nase carp (Chondrostoma nasus L.) were observed alongside dissimilar shoreline configurations in the main channel of the free-flowing Austrian Danube and compared with those of floating particles to investigate the mode of dispersal (active–passive). Individuals of different larval stages and floats at similar densities were released at an artificial rip-rap with groynes and a rehabilitated gravel bar. In both habitats, marked individuals were recaptured during the sampling period of 4 d after release. Relevant shoreline attributes for larval dispersal, such as the accessibility of nursery habitats, connectivity between adjacent habitats, and retention potential, were more pronounced at the gravel bar than at the rip-rap. At the gravel bar, larvae moved upstream and downstream within the connected bankside nurseries and displayed longer residence times. Larvae settled in groyne fields along the rip-rap as well; however, longitudinal dispersal was disrupted by groynes, forcing larvae to enter the main channel. Rather than settling in subsequent groyne fields, we assume that these larvae are displaced downstream and potentially lost from the local population.
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Chan, Kit Yu Karen, Mary A. Sewell i Maria Byrne. "Revisiting the larval dispersal black box in the Anthropocene". ICES Journal of Marine Science 75, nr 6 (10.08.2018): 1841–48. http://dx.doi.org/10.1093/icesjms/fsy097.
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Abstract Many marine organisms have a multi-phase life history and rely on their planktonic larvae for dispersal. Despite the important role of larvae in shaping population distribution and abundance, the chemical, physical, and biological factors that shape larval fate are still not fully understood. Shedding light into this larval dispersal “black box” has become critical in the face of global climate change, primarily due to the importance of larval dispersal in formulating sound conservation and management strategies. Focusing on two major stressors, warming and acidification, we highlight the limitations of the current species-by-species, lab-based study approach, and particularly the lack of consideration of the larval experience along the dispersive pathway. Measuring organismal responses to environmentally relevant climate change stress demands an improved documentation of the physical and biological conditions that larvae experience through ontogeny, which in turn requires updated empirical and theoretical approaches. While there are meaningful between taxa comparisons to be made by larval ecologists, to peek into the dispersal black box and to investigate the larger scale consequences of altered dispersal requires innovative collaborations between ecologists, oceanographers, molecular biologists, statisticians, and mathematicians.
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Leis, JM. "Measurement of swimming ability in larval marine fishes: comparison of critical speed with in situ speed". Marine Ecology Progress Series 650 (17.09.2020): 203–15. http://dx.doi.org/10.3354/meps13233.
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For much of their pelagic larval dispersal (PLD) stage, larval perciform fishes are able to directly influence their dispersal by horizontal swimming, but it is unclear which means of measuring swimming ability is most appropriate for modelling dispersal and studying demographic and genetic connectivity. Most studies use critical speed (Ucrit), a laboratory flume measure derived by increasing flow until larvae can no longer maintain their position. Most swimming ability data on fish larvae are Ucrit, usually for larvae nearing the end of PLD. Recognizing that a forced laboratory measure is inappropriate for dispersal, researchers have used decreased Ucrit values, usually by 50%, and have argued that Ucrit is strongly correlated with more relevant swimming measures. Here I examined the suitability of Ucrit versus in situ speed (ISS), wherein speed of larvae is measured by divers following them in the ocean with a flow meter. Considerations of dispersal require inclusion of swimming ontogeny. Swimming speed regressions of speed on size of 10 species in 8 families showed that Ucrit and ISS are not well correlated. The Ucrit:standard length (SL) slope was greater than the ISS:SL slope in 6 species, and did not differ in the other 4 species. No overall metric, e.g. X% of Ucrit = ISS, was appropriate for conversion of Ucrit to ISS. Conversion of Ucrit to ISS is not straightforward. Ucrit measures swimming potential, not what larvae do in the ocean, whereas ISS directly measures larvae swimming in the ocean. Ucrit ontogeny is less variable, but ISS ontogeny is more relevant to dispersal. Ucrit may be useful for other purposes.
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Weseloh, Ronald M. "Dispersal and survival of gypsy moth larvae". Canadian Journal of Zoology 65, nr 7 (1.07.1987): 1720–23. http://dx.doi.org/10.1139/z87-265.
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Marked, laboratory-reared gypsy moth, Lymantria dispar L., second instars were released at the base of oak trees in a declining gypsy moth population. By periodically noting the proportion of caterpillars observed that had been released, it was found that little intertree dispersal of second and third instars occurred. Movement within a tree did occur, however. Dispersal of gypsy moth fourth through sixth instars was measured by determining changes in the proportion of marked caterpillars resting under burlap bands placed around the trunks of isolated trees. Results suggest that large larvae disperse little except just prior to pupation. The lack of significant dispersal in all larval stages made it possible to estimate from mark–recapture studies the proportion of larvae that survive from one day to the next. Daily survival rates were 0.6–0.7 for small larvae and ca. 0.8 for large ones.
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Dale, Katherine E., M. Timothy Tinker i Rita S. Mehta. "Larval morphology predicts geographical dispersal range of Eastern Pacific eels". Biological Journal of the Linnean Society 128, nr 1 (27.06.2019): 107–21. http://dx.doi.org/10.1093/biolinnean/blz092.
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Abstract The geographical range of many marine species is strongly influenced by the dispersal potential of propagules such as eggs and larvae. Here, we investigate morphological diversity and the effect of body shape on geographical range of leptocephali, the unique, laterally compressed larvae of eels (order Anguilliformes). We used phylogenetically informed analyses to examine the morphological variation of larvae for 17 Eastern Pacific eel species from three adult habitats. We also investigated whether morphological traits of leptocephali could predict larval latitudinal range, hypothesizing that body shape may influence passive dispersal via currents. We found that no two species shared the same multivariate growth trajectories, with the size and scaling of pectoral fin length and snout-to-anus length being particularly variable. Larvae with longer relative predorsal and snout-to-anus lengths at median sizes exhibited wider larval geographical ranges. Body aspect ratio and maximum body length at metamorphosis, two traits we hypothesized to be important for passive transport, were not significant predictors of maximal larval range. We discovered an increase in phylogenetic signal over larval development as eels approach metamorphosis, potentially due to similar selective pressures between related species (such as juvenile habitat or adult morphology). Lastly, we conclude that larval body shape is probably influenced by adult habitat and adult morphology.
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Pedersen, Eric J., Ryan R. E. Stanley, Paul V. R. Snelgrove i Frédéric Guichard. "Experimental evidence for concentration-dependence and intraspecific variation of movement behaviour in American lobster (Homarus americanus) larvae". Canadian Journal of Zoology 95, nr 10 (październik 2017): 759–70. http://dx.doi.org/10.1139/cjz-2016-0100.
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Predicting dispersal paths of marine larvae with extended pelagic durations, such as American lobster (Homarus americanus H. Milne Edwards, 1837), requires understanding the cues to which larvae respond, and how that response reflects changes in larval behaviour. If larvae respond to conspecific presence by varying their movement, then this behaviour can bias laboratory estimates of environmental responses. We tested whether larvae actively decreased their local intraspecific density by measuring how the vertical distribution of larvae changed under high versus low concentrations of conspecifics. We observed weak increases in vertical dispersion at higher concentrations both in newly hatched larvae and in postlarvae, but not in intermediate larval stages. We also tested for differences in horizontal swimming behaviour in high and low concentrations, by fitting a novel random walk model that allowed us to model both larval interactions and persistent turning behaviours. We showed substantial reduction in diffusive behaviour under high concentration conditions resulting from more frequent turns by each larva, but no evidence for consistent avoidance of conspecifics. Our study is the first to demonstrate concentration-dependent behaviours in lobster larvae.
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Berger, Amelie. "Larval movements of Chilo partellus (Lepidoptera: Pyralidae) within and between plants: timing, density responses and survival". Bulletin of Entomological Research 82, nr 4 (grudzień 1992): 441–48. http://dx.doi.org/10.1017/s0007485300042498.
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AbstractFour dispersal phases occur during larval development of Chilo partellus (Swinehoe) on young host plants, phase 1, ballooning of newly hatched larvae when moving from egg batch to plant whorl, phase 2, ballooning of first and second instars which leave the plant whorl in the week after egg eclosion, phase 3, walking prior to stem penetration, and phase 4, walking after stem penetration. In laboratory experiments larval dispersal was density dependent during dispersal phases 1, 3 and 4 and there were clear differences between maize and sorghum in the percentage of migrating lavae and time of migration. Maize plants accommodated many more pupae than sorghum plants which suggests that the distribution of older larvae in the field can be more clumped in maize than in sorghum. Pupal weight descreased with infestation level on sorghum but seemed less affected on maize. Resistance to starvation in four combinations of temperature and relative humidity increased with age. All hatchlings survived six hours′ starvation but with considerably reduced crawling capacity. Seven- and 15-day old larvae were descreasingly affected. Older larvae survived and maintained their mobility after 48 hours. Successful dispersal will depend on host-plant, egg load, and costs of migration; these costs will change with larval age.
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de Lima, Francielly A., Terezinha Ferreira de Oliveira i Jussara M. Martinelli-Lemos. "Distribution of brachyuran larvae in an Amazonian estuary as evidence for retention and export". Journal of Crustacean Biology 39, nr 5 (13.08.2019): 602–12. http://dx.doi.org/10.1093/jcbiol/ruz051.
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Abstract Brachyuran crabs, like other decapod crustaceans, adopt a number of different strategies for larval dispersal. We verified the influence of variations in temperature, salinity, and pH on the abundance and taxonomic composition of brachyuran larvae in an Amazonian estuary and found evidence of both retention and export dispersal strategies. We identified larvae of 20 different taxa belonging to the families Grapsidae, Ocypodidae, Panopeidae, Pinnotheridae, and Sesarmidae. Ucides cordatus (Linnaeus, 1763) (Ocypodidae), Pachygrapsus gracilis (Saussure, 1857) (Grapsidae), Leptuca cumulanta (Crane, 1943) (Ocypodidae), and Armases rubripes (Rathbun, 1897) (Sesarmidae) were the most abundant species. Most of the taxa present in the study area were at the zoea I stage but later larval stages were found in some species, indicating retention and export. Results were supported by canonical correspondence analysis and general linear model, which related larval community structure and reproduction patterns to variations in salinity, influenced primarily by the enormous discharge of the Amazon River and the high rainfall levels in the region. Further investigations of the distribution of larvae on the continental shelf are necessary to confirm the identified dispersal patterns. The study also presents novel data on the composition, abundance, and dispersal of brachyuran larvae in the tropical estuaries of the Amazon River.
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Schludermann, Elisabeth, Michael Tritthart, Paul Humphries i Hubert Keckeis. "Dispersal and retention of larval fish in a potential nursery habitat of a large temperate river: an experimental study". Canadian Journal of Fisheries and Aquatic Sciences 69, nr 8 (sierpień 2012): 1302–15. http://dx.doi.org/10.1139/f2012-061.
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Little information is available on governing factors of larval fish dispersal in natural river systems. Therefore, we aimed to describe dispersal and retention of marked larval nase carp, Chondrostoma nasus , along a shoreline nursery habitat of the River Danube. Based on a three-dimensional hydrodynamic model, we analyzed the influence of the hydraulic conditions on larval dispersal. We also related observed larval pathways to numerical particle tracing. Clear differences in the temporal drift pattern were due to significant differences in the hydrodynamic characteristics of the release stations. Some larvae remained in the study reach, most upstream of the release point. These were significantly larger than drifting larvae. We conclude that larval dispersal has an active component and that dispersal and retention patterns are dependent on the habitat structure and hydrodynamic characteristics of the releasing points. This emphasizes the importance of links between the location of spawning sites within the river and variation in flow during early development, the combination of which may contribute to successful recruitment of fluvial fish species.
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Ziegler, Amanda F., Lisa Hahn-Woernle, Brian Powell i Craig R. Smith. "Larval Dispersal Modeling Suggests Limited Ecological Connectivity Between Fjords on the West Antarctic Peninsula". Integrative and Comparative Biology 60, nr 6 (3.07.2020): 1369–85. http://dx.doi.org/10.1093/icb/icaa094.
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Synopsis Larval dispersal is a key process for community assembly and population maintenance in the marine environment, yet it is extremely difficult to measure at ecologically relevant spatio-temporal scales. We used a high-resolution hydrodynamic model and particle-tracking model to explore the dispersal of simulated larvae in a hydrographically complex region of fjords on the West Antarctic Peninsula. Modeled larvae represented two end members of dispersal potential observed in Antarctic benthos resulting from differing developmental periods and swimming behavior. For simulations of low dispersing larvae (pre-competency period = 8 days, settlement period = 15 days, swimming downward) self-recruitment within fjords was important, with no larval settlement occurring in adjacent fjords <50 km apart. For simulations of highly dispersing organisms (pre-competency period = 35–120 days, settlement period = 30–115 days, no swimming behavior), dispersal between fjords occurred when larvae were in the water column for at least 35 days, but settlement was rarely successful even for larvae spending up to 150 days in the plankton. The lack of ecological connectivity between fjords within a single spawning event suggests that these fjords harbor ecologically distinct populations in which self-recruitment may maintain populations, and genetic connectivity between fjords is likely achieved through stepping-stone dispersal. Export of larvae from natal fjord populations to the broader shelf region (>100 km distance) occurred within surface layers (<100 m depth) and was enhanced by episodic katabatic wind events that may be common in glaciomarine fjords worldwide.
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Oliveira, Diego Leandro, Taciano Moura Barbosa, Artur C. D. Maia i Simão Dias Vasconcelos. "Development and Field Evaluation of a Novel, Inexpensive Passive Trap for Monitoring Dispersal of Necrophagous Dipteran Larvae". Journal of Economic Entomology 112, nr 5 (30.05.2019): 2497–501. http://dx.doi.org/10.1093/jee/toz147.
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Abstract Techniques for the survey of necrophagous dipterans are frequently designed for adult flies and often neglect forensically important information, such as the postfeeding larval dispersal following carcass colonization. In this study, we propose and test a novel trap design for the collection of dipteran larvae at the postfeeding stage. The Trap for Dispersing Larvae (TDL) consists of two semiindependent parts: 1) a 2-liter PET bottle, containing the attractant (carcass); and 2) a plastic box, which selectively captures postfeeding dispersing larvae. Based on a field test in a dry forest fragment in Brazil, the TDL trap captured ca. 1,500 larvae of 13 species of Calliphoridae, Muscidae, Fanniidae, and Sarcophagidae. The species richness of dispersing larvae recorded in our study was ca. 60% of that previously recorded in this area. As the TDL trap can assess larval dispersal without interfering with carcass decomposition, we demonstrate that it can be used to assess temporal variation in the dynamics of colonization. In the present study, most larval dispersal occurred at 5-d postexposure, but the traps remained efficient until 7 d, by which time rat carcasses had skeletonized. We conclude that the TDL trap captures the dispersing dipteran larvae with little interference in carcass decomposition processes. The trap also provides a representative sample of species and is simple to use and of low cost.
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Rodriguez-Perez, Ana, Mark A. James i William G. Sanderson. "A small step or a giant leap: Accounting for settlement delay and dispersal in restoration planning". PLOS ONE 16, nr 8 (18.08.2021): e0256369. http://dx.doi.org/10.1371/journal.pone.0256369.
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Understanding larval duration and hence dispersal potential of the European oyster Ostrea edulis is crucial to inform restoration strategies. Laval duration has an obligatory period of maturity to pediveliger (when larvae are ready to settle), but also an unknown period until metamorphosis is triggered by a settlement cue. The extent to which larvae can prolong the pediveliger period and delay metamorphosis has not been studied. Here we show that O. edulis larvae can delay metamorphosis for a period of 11 days, while retaining the capability to settle in high proportions when presented with a suitable settlement cue. O. edulis larvae are likely to be able to delay metamorphosis even further, since 80% of larvae in the control treatment were still alive when the experiment was terminated at day 14. The results indicate the ability of O. edulis larvae to more than double pelagic duration and probably further delay metamorphosis. We discuss these findings in the context of larval mortality, and the importance of O. edulis’ larval settlement requirements for dispersal potential, recruitment success and connectivity of restoration sites.
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Winch, Judith M., i J. Riley. "Studies on the behaviour, and development in fish, ofSubtriquetra subtriquetra: a uniquely free-living pentastomid larva from a crocodilian". Parasitology 93, nr 1 (sierpień 1986): 81–98. http://dx.doi.org/10.1017/s0031182000049842.
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SUMMARYThe primary larva of the porocephalid pentastomidSubtriquetra subtriquetra, which infects the nasopharynx ofCaiman sclerops, is uniquely free-living. Eggs hatch within the nasal passages and the emergent larvae can remain infective to the fish intermediate host for 4–5 days. During this period larvae exhibit very stereotyped behaviour, alternating between a characteristic stationary ‘fishing’ posture and very brief periods of movement. Larval activity increases significantly at 3 days, probably effecting dispersal to a more favourable site for host invasion. Host location is passive and invading larvae penetrate to the swim-bladder where subsequent larval development, which involves 7 moults, occurs. All 8 larval stages are freely mobile in the swim-bladder and possess hooks. Sensilla, disposed in characteristic patterns, are present throughout development, increasing in number to the infective stage; the majority of sensilla are located on sensory papillae.
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Leis, Jeffrey M. "Perspectives on Larval Behaviour in Biophysical Modelling of Larval Dispersal in Marine, Demersal Fishes". Oceans 2, nr 1 (22.12.2020): 1–25. http://dx.doi.org/10.3390/oceans2010001.
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Biophysical dispersal models for marine fish larvae are widely used by marine ecologists and managers of fisheries and marine protected areas to predict movement of larval fishes during their pelagic larval duration (PLD). Over the past 25 years, it has become obvious that behaviour—primarily vertical positioning, horizontal swimming and orientation—of larvae during their PLD can strongly influence dispersal outcomes. Yet, most published models do not include even one of these behaviours, and only a tiny fraction include all three. Furthermore, there is no clarity on how behaviours should be incorporated into models, nor on how to obtain the quantitative, empirical data needed to parameterize models. The PLD is a period of morphological, physiological and behavioural change, which presents challenges for modelling. The present paper aims to encourage the inclusion of larval behaviour in biophysical dispersal models for larvae of marine demersal fishes by providing practical suggestions, advice and insights about obtaining and incorporating behaviour of larval fishes into such models based on experience. Key issues are features of different behavioural metrics, incorporation of ontogenetic, temporal, spatial and among-individual variation, and model validation. Research on behaviour of larvae of study species should be part of any modelling effort.
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Arellano, Shawn M., Ahna L. Van Gaest, Shannon B. Johnson, Robert C. Vrijenhoek i Craig M. Young. "Larvae from deep-sea methane seeps disperse in surface waters". Proceedings of the Royal Society B: Biological Sciences 281, nr 1786 (7.07.2014): 20133276. http://dx.doi.org/10.1098/rspb.2013.3276.
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Many species endemic to deep-sea methane seeps have broad geographical distributions, suggesting that they produce larvae with at least episodic long-distance dispersal. Cold-seep communities on both sides of the Atlantic share species or species complexes, yet larval dispersal across the Atlantic is expected to take prohibitively long at adult depths. Here, we provide direct evidence that the long-lived larvae of two cold-seep molluscs migrate hundreds of metres above the ocean floor, allowing them to take advantage of faster surface currents that may facilitate long-distance dispersal. We collected larvae of the ubiquitous seep mussel “Bathymodiolus” childressi and an associated gastropod, Bathynerita naticoidea , using remote-control plankton nets towed in the euphotic zone of the Gulf of Mexico. The timing of collections suggested that the larvae might disperse in the water column for more than a year, where they feed and grow to more than triple their original sizes. Ontogenetic vertical migration during a long larval life suggests teleplanic dispersal, a plausible explanation for the amphi-Atlantic distribution of “B.” mauritanicus and the broad western Atlantic distribution of B. naticoidea . These are the first empirical data to demonstrate a biological mechanism that might explain the genetic similarities between eastern and western Atlantic seep fauna.
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Leis, Jeffrey M., Richard F. Piola, Amanda C. Hay, Colin Wen i Kun-Ping Kan. "Ontogeny of behaviour relevant to dispersal and connectivity in the larvae of two non-reef demersal, tropical fish species". Marine and Freshwater Research 60, nr 3 (2009): 211. http://dx.doi.org/10.1071/mf08186.
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In demersal marine fishes, the dispersal of larvae determines the geographical scale of population connectivity, and larval behaviour may influence dispersal. Yet, little is known of the ontogeny of behaviours that can influence dispersal. The present study examined the development of these behaviours in pelagic larvae of tropical marine fishes (4–21 mm) that occupy non-reef habitats as adults: Eleutheronema tetradactylum (Polynemidae) and Leiognathus equulus (Leiognathidae). In the laboratory, critical speed (Ucrit) increased from 3 to 34 cm s–1 at 1.3–1.7 cm s–1 per mm of size, with the fastest larvae up to 50% faster. In situ speed increased from 4 to 25 cm s–1 at 0.7–2.2 cm s–1 per mm, and was 10–14 body length s–1 (60–90% of Ucrit). Endurance increased from 0 to >40 km at 2.4–4.7 km per mm. In the sea, orientation precision did not change ontogenetically, both species tended to swim in loops, and neither significant overall directionality nor ontogenetic change in orientation was present. Larval orientation of these non-reef species was less precise than that of reef fishes. The two species differed in depth distribution, and one ascended ontogenetically. These behaviours can potentially influence dispersal outcomes over the full size range of these larvae.
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Chenoweth, S. B., D. A. Libby, R. L. Stephenson i M. J. Power. "Origin and Dispersion of Larval Herring (Clupea harengus) in Coastal Waters of Eastern Maine and Southwestern New Brunswick". Canadian Journal of Fisheries and Aquatic Sciences 46, nr 4 (1.04.1989): 624–32. http://dx.doi.org/10.1139/f89-079.
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Repetitive surveys of larval herring (Clupea harengus) were undertaken in coastal waters between Mt. Desert, Maine and Saint John, New Brunswick to define the location, timing, and extent of spawning and the distribution of larvae. Three surveys during September and October 1986 showed two separate areas of larval dispersal. The easternmost stations contained low densities of large larvae which were assumed to be part of the annually occurring larval aggregation off Nova Scotia. High densities of small larvae west of Grand Manan indicated that spawning in this area was confined to a small area southwest of Grand Manan and along the eastern Maine coast. This unique larval distribution confirms the autonomous nature of the eastern Maine–Grand Manan spawning group. Back calculation indicated hatching times between late July and the middle of October, but most of the larvae taken in the survey hatched in August and September. The larvae west of Grand Manan occurred within a well mixed water mass containing a characteristic neritic zooplankton community. Some larval herring remained near the spawning ground over a 2-mo period, while others dispersed west along the coast.
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León, Roxana, Leonardo R. Castro i Mario Cáceres. "Dispersal of Munida gregaria (Decapoda: Galatheidae) larvae in Patagonian channels of southern Chile". ICES Journal of Marine Science 65, nr 7 (16.06.2008): 1131–43. http://dx.doi.org/10.1093/icesjms/fsn093.
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Abstract León, R., Castro, L. R., and Cáceres, M. 2008. Dispersal of Munida gregaria (Decapoda: Galatheidae) larvae in Patagonian channels of southern Chile. – ICES Journal of Marine Science, 65: 1131–1143. The dispersal of Munida gregaria larvae in Chilean Patagonian channels was assessed in spring 2002 and 2003, and winter 2003. In winter 2003, zoea I was the most abundant stage in all channels and there were no larval stages older than zoea IV. In spring 2002 and 2003, there were six larval stages in all channels, and the greater abundance of older larvae suggested that reproduction takes place in winter and larval development in spring. Further, analysis of spatial distribution by stage revealed that early zoeae moved seawards. Generalized Additive Models analyses showed that most larval stages were temperature-dependent, and that the salinity range of the youngest zoea was wider than that of older larvae and post-larvae, coinciding with an ontogenetic distribution change from estuary to shelf. Residual flows determined with an acoustic Doppler current profiler revealed two layers of opposite flow: the shallowest layer moved seawards and the deeper layer onshore. The surface layer was wider in spring than in winter because of seasonal increase in fresh-water input. The dispersal pattern of M. gregaria consisted of an inner channel larval release in winter, followed by an along-channel larval drift and subsequent export to the shelf in spring. The mechanism by which juveniles return to the channels seemed to be associated with the onshore subsurface flow.
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Tian, Rucheng C., Changsheng Chen, Kevin D. E. Stokesbury, Brian J. Rothschild, Geoffrey W. Cowles, Qichun Xu, Song Hu, Bradley P. Harris i Michael C. Marino. "Dispersal and settlement of sea scallop larvae spawned in the fishery closed areas on Georges Bank". ICES Journal of Marine Science 66, nr 10 (23.06.2009): 2155–64. http://dx.doi.org/10.1093/icesjms/fsp175.
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Abstract Tian, R. C., Chen, C., Stokesbury, K. D. E., Rothschild, B. J., Cowles, G. W., Xu, Q., Hu, S., Harris, B. P., and Marino II, M. C. 2009. Dispersal and settlement of sea scallop larvae spawned in the fishery closed areas on Georges Bank. – ICES Journal of Marine Science, 66: 2155–2164. Three fishery closed areas in the Georges Bank (GB) region were implemented in 1994 to protect depleted groundfish stocks for population replenishment. However, the drift and ultimate destination of larvae spawned in the closed areas have not been analysed specifically within the framework of ocean currents. To assess the efficiency of the closed areas as population replenishment sources, we conducted a simulation-based analysis on the dispersal and settlement of sea scallop larvae spawned in the closed areas from 1995 to 2005 using circulation fields computed by the Finite-Volume Coastal Ocean Model, scallop survey data, and a population dynamics model. Closed area I located in the Great Southern Channel (GSC) had a persistently high rate of larval retention (86% on average). For closed area II located on eastern GB, a considerable quantity of larvae was dispersed out of the domain. For the Nantucket Lightship Closed Area located on Nantucket Shoals, larvae consistently drifted away from the region during the 11 years simulated. Our simulation revealed three high-retention regions that are the most suitable for closed-area selection and rotational fishery management in terms of larval supply to the GB–GSC region.
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Sasaki, R., i SA Shepherd. "Larval dispersal and recruitment of Haliotis discus hannai and Tegula spp. on Miyagi coasts, Japan". Marine and Freshwater Research 46, nr 3 (1995): 519. http://dx.doi.org/10.1071/mf9950519.
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The spatial dispersal and vertical distribution of larvae of Haliotis discus hannai and Tegula spp. were examined in relation to storm events in Miyagi Prefecture, Japan, from 1983 to 1993. Epidemic spawning is induced by typhoons and minor storms. After typhoons, larvae are dispersed in coastal waters up to 3 km from shore to a depth of 30 m and later are advected toward the coast by onshore winds. After minor storms, larvae are locally dispersed close to shore. Larvae of H. discus hannai and Tegula spp. become vertically stratified and settle on the substratum at depths in accordance with the vertical depth range of their larvae. Strong settlements of H. discus hannai of up to 200 m-2 were recorded around headlands, with average survival rates of about 13% per month in the first 2-3 months. The adaptive significance of dispersal over short and long distances is considered.
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Thiébaut, E., J. C. Dauvin i Y. Lagadeuc. "Horizontal distribution and retention of Owenia fusiformis larvae (Annelida: Polychaeta) in the Bay of Seine". Journal of the Marine Biological Association of the United Kingdom 74, nr 1 (luty 1994): 129–42. http://dx.doi.org/10.1017/s0025315400035712.
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Between 8 May and 3 June 1987 horizontal distribution of Owenia fusiformis larvae (Annelida: Polychaeta) was studied in the eastern part of the Bay of Seine on two spatial scales to determine the role of larval dispersal by hydrodynamic factors on the population dynamics of a benthopelagic species. Larval dispersal occurred in two main directions, north-west and north-east, according to the residual tidal circulation. There was a substantial transport of larvae to a distance of 30–40 NM (48–65 km) from their emission point, resulting in a sizeable loss of larvae to the adult population. However, their densities were low in comparison with those observed in the eastern part of the bay, near the adult population. Larval densities remained highest near the adult population, principally under the influence of tidal processes. In contrast, there was a significant wind-induced larval movement at a time scale of a few days. The action of wind at a time scale of one month, the duration of larval life, appeared to be insignificant for dispersal in 1987 because of the frequent changes in wind direction. Climatological data collected between 1951 and 1980 showed that the wind effect observed in 1987 is probably typical of most years. The horizontal transport of Owenia fusiformis larvae, combined with the ontogenic vertical migration observed previously, causes a retention of these larvae in the eastern part of the Bay of Seine; this favours recruitment and may be one of the factors explaining the temporal stability of the adult population.
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Miller, J. A., i A. L. Shanks. "Evidence for limited larval dispersal in black rockfish (Sebastes melanops): implications for population structure and marine-reserve design". Canadian Journal of Fisheries and Aquatic Sciences 61, nr 9 (1.09.2004): 1723–35. http://dx.doi.org/10.1139/f04-111.
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Although dispersal distances of marine larvae influence gene flow and the establishment of population structure, few data on realized dispersal distances exist for marine species. We combined otolith microstructure and micro chemistry of black rockfish (Sebastes melanops) to assess their potential to provide relative estimates of larval dispersal distance. In 2001 and 2002 we measured trace elements at discrete otolith regions, representing the (i) egg/early-larval, (ii) pelagic larval, and (iii) late-larval/early-juvenile periods of fish collected at three locations 120460 km apart. Discriminant-function analyses based on geochemical signatures at each otolith region accurately grouped an average of 85% (jackknife = 67%) and 87% (jackknife = 81%) of the fish to collection location in 2001 and 2002, respectively. Age at collection ranged from 83 to 174 days and parturition dates within each site were spread over a 22- to 66-day period. Therefore, individuals within sites were not released at similar times. A probable explanation of these data is that larvae from different geographic locations did not mix during ontogeny and possibly did not disperse long distances alongshore. Larval dispersal distances may be appreciably shorter, <120 km, than previously assumed based on models of passive dispersal.
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Staaterman, Erica, i Claire B. Paris. "Modelling larval fish navigation: the way forward". ICES Journal of Marine Science 71, nr 4 (24.08.2013): 918–24. http://dx.doi.org/10.1093/icesjms/fst103.
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Abstract Recent advances in high-resolution ocean circulation models, coupled with a greater understanding of larval behaviour, have increased the sophistication of individual-based, biophysical models used to study the dispersal of larvae in the sea. Fish larvae, in particular, have the ability to swim directionally and increasingly fast during ontogeny, indicating that they may not only disperse, but also migrate using environmental signals. How and when larvae use local and large-scale cues remains a mystery. Including three-dimensional swimming schemes into biophysical models is becoming essential to address these questions. Here, we highlight state-of-the-art modelling of vertical and horizontal migrations of fish larvae, as well as current challenges in moving towards more realistic larval movements in response to cues. Improved understanding of causes for orientation will provide insight into the evolutionary drivers of dispersal strategies for fish and marine organisms in general.
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Shima, Jeffrey S., Erik G. Noonburg i Stephen E. Swearer. "Consequences of variable larval dispersal pathways and resulting phenotypic mixtures to the dynamics of marine metapopulations". Biology Letters 11, nr 2 (luty 2015): 20140778. http://dx.doi.org/10.1098/rsbl.2014.0778.
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Larval dispersal can connect distant subpopulations, with important implications for marine population dynamics and persistence, biodiversity conservation and fisheries management. However, different dispersal pathways may affect the final phenotypes, and thus the performance and fitness of individuals that settle into subpopulations. Using otolith microchemical signatures that are indicative of ‘dispersive’ larvae (oceanic signatures) and ‘non-dispersive’ larvae (coastal signatures), we explore the population-level consequences of dispersal-induced variability in phenotypic mixtures for the common triplefin (a small reef fish). We evaluate lipid concentration and otolith microstructure and find that ‘non-dispersive’ larvae (i) have greater and less variable lipid reserves at settlement (and this variability attenuates at a slower rate), (ii) grow faster after settlement, and (iii) experience similar carry-over benefits of lipid reserves on post-settlement growth relative to ‘dispersive’ larvae. We then explore the consequences of phenotypic mixtures in a metapopulation model with two identical subpopulations replenished by variable contributions of ‘dispersive’ and ‘non-dispersive’ larvae and find that the resulting phenotypic mixtures can have profound effects on the size of the metapopulation. We show that, depending upon the patterns of connectivity, phenotypic mixtures can lead to larger metapopulations, suggesting dispersal-induced demographic heterogeneity may facilitate metapopulation persistence.
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Shulzitski, Kathryn, Su Sponaugle, Martha Hauff, Kristen Walter, Evan K. D'Alessandro i Robert K. Cowen. "Close encounters with eddies: oceanographic features increase growth of larval reef fishes during their journey to the reef". Biology Letters 11, nr 1 (styczeń 2015): 20140746. http://dx.doi.org/10.1098/rsbl.2014.0746.
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Like most benthic marine organisms, coral reef fishes produce larvae that traverse open ocean waters before settling and metamorphosing into juveniles. Where larvae are transported and how they survive is a central question in marine and fisheries ecology. While there is increasing success in modelling potential larval trajectories, our knowledge of the physical and biological processes contributing to larval survivorship during dispersal remains relatively poor. Mesoscale eddies (MEs) are ubiquitous throughout the world's oceans and their propagation is often accompanied by upwelling and increased productivity. Enhanced production suggests that eddies may serve as important habitat for the larval stages of marine organisms, yet there is a lack of empirical data on the growth rates of larvae associated with these eddies. During three cruises in the Straits of Florida, we sampled larval fishes inside and outside five cyclonic MEs. Otolith microstructure analysis revealed that four of five species of reef fish examined had consistently faster growth inside these eddies. Because increased larval growth often leads to higher survivorship, larvae that encounter MEs during transit are more likely to contribute to reef populations. Successful dispersal in oligotrophic waters may rely on larval encounter with such oceanographic features.
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Čičková, H., M. Kozánek i P. Takáč. "Improvement of survival of the house fly (Musca domestica L.) larvae under mass-rearing conditions". Bulletin of Entomological Research 103, nr 1 (22.10.2012): 119–25. http://dx.doi.org/10.1017/s000748531200065x.
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AbstractTwo new approaches were examined, aimed at increasing survival of the house fly (Musca domestica L.) larvae under mass-rearing conditions of a biodegradation facility: modification of the larval substrate and dispersal of the eggs during inoculation. The two types of pig manure used in this study (manure with sawdust and manure without sawdust) differed in terms of larval survival and nutritional value for the house fly larvae. Larval survival in manure without sawdust in the control treatment was low (46.8 ± 2.1%) and its nutritional value for the larvae were high. Addition of 5.7% of previously biodegraded manure did not significantly affect larval survival (52.3 ± 1.9%), but larval development was faster and the pupae were significantly smaller (14.28 ± 0.4 mg) compared to the control (16.29 ± 0.5 mg). Using alternative substrate for incubation of eggs and first-instar larvae significantly increased larval survival (63.3 ± 3.3%) and decreased the mean weight of produced pupae (14.39 ± 0.71 mg). Overall, the weight of recovered biomass in the alternative substrate treatment increased by 14.3 kg ton−1 of manure compared to the control. Larval survival in manure with sawdust was generally higher than 70%, but its nutritional value for the larvae was lower than in manure without sawdust. Dispersal of eggs over the surface of manure with sawdust significantly affected larval survival and mean weight of pupae. Larval survival was significantly lower (59.2 ± 4.0%) and pupae were significantly heavier (18.45 ± 0.8 mg) when eggs were applied to a small area on the manure surface (spot treatment), as compared to diagonal, Z-line and multiple zig-zag dispersal (72.5 ± 2.4 to 74.6 ± 3.0% and 14.76 ± 0.6 to 15.97 ± 0.6 mg, respectively). No significant differences were observed in larval survival or mean weight of pupae when comparing the diagonal, Z-line and multiple zig-zag dispersal patterns. Implementation of the techniques which improve larval survival and increase the weight of produced fly biomass may decrease demand for production of house fly eggs and, therefore, reduce the maintenance costs of adult colony, as well as increase the revenue earned by selling the products.
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Bradbury, I. R., K. Gardiner, P. VR Snelgrove, S. E. Campana, P. Bentzen i L. Guan. "Larval transport, vertical distribution, and localized recruitment in anadromous rainbow smelt (Osmerus mordax)". Canadian Journal of Fisheries and Aquatic Sciences 63, nr 12 (1.12.2006): 2822–36. http://dx.doi.org/10.1139/f06-164.
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We examined larval dispersal and behaviour in rainbow smelt (Osmerus mordax) from the Salmonier River estuary, Newfoundland, during 2003–2005. Riverine ichthyoplankton surveys indicate that larval transport into the estuary is restricted to a two-week period in late June. A passive drifter experiment and the spatial distribution of larvae and juveniles suggest limited dispersal and low export from the estuary. The estuary exhibited low inflow and stratification in summer and high inflow with a stable freshwater layer in fall. Summer and fall winds are primarily onshore. We hypothesised that larval vertical swimming behaviour limits dispersal and export. Larval vertical position and swimming ability were examined through lab-based experiments conducted 0–10 and 90 days after hatching. Measurements of swim speed indicate an order of magnitude (p < 0.001) improvement in swimming capacity between larvae and juveniles. One-week after hatching, larvae displayed consistent negative geotaxis, whereas juveniles were generally deeper and displayed negative geotaxis in light and positive geotaxis in the dark. The contrasting light-mediated geotactic behavior between development stages corresponds to ontogenetic shifts in swimming abilities and seasonal changes in estuarine circulation. We suggest that the interaction between behaviour, ontogeny, and hydrography results in limited transport and a tendency for estuarine-scale recruitment, despite an extensive pelagic period.
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Kough, Andrew S., Claire B. Paris, Donald C. Behringer i Mark J. Butler. "Modelling the spread and connectivity of waterborne marine pathogens: the case of PaV1 in the Caribbean". ICES Journal of Marine Science 72, suppl_1 (21.11.2014): i139—i146. http://dx.doi.org/10.1093/icesjms/fsu209.
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AbstractThe PaV1 virus infects spiny lobsters (Panulirus argus) throughout most of the Caribbean, where its prevalence in adult lobsters can reach 17% and where it poses a significant risk of mortality for juveniles. Recent studies indicate that vertical transmission of the virus is unlikely and PaV1 has not been identified in the phyllosoma larval stages. Yet, the pathogen appears subclinically in post-larvae collected near the coast, suggesting that lobster post-larvae may harbour the virus and perhaps have aided in the dispersal of the pathogen. Laboratory and field experiments also confirm the waterborne transmission of the virus to post-larval and early benthic juvenile stages, but its viability in the water column may be limited to a few days. Here, we coupled Lagrangian modelling with a flexible matrix model of waterborne and post-larval-based pathogen dispersal in the Caribbean to investigate how a large area with complex hydrology influences the theoretical spread of disease. Our results indicate that if the virus is waterborne and only viable for a few days, then it is unlikely to impact both the Eastern and Northwestern Caribbean, which are separated by dispersal barriers. However, if PaV1 can be transported between locations by infected post-larvae, then the entire Caribbean becomes linked by pathogen dispersal with higher viral prevalence in the North. We identify possible regions from which pathogens are most likely to spread, and highlight Caribbean locations that function as dispersal “gateways” that could facilitate the rapid spread of pathogens into otherwise isolated areas.
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Wren, Johanna L. K., i Donald R. Kobayashi. "Exploration of the “larval pool”: development and ground-truthing of a larval transport model off leeward Hawai‘i". PeerJ 4 (1.02.2016): e1636. http://dx.doi.org/10.7717/peerj.1636.
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Most adult reef fish show site fidelity thus dispersal is limited to the mobile larval stage of the fish, and effective management of such species requires an understanding of the patterns of larval dispersal. In this study, we assess larval reef fish distributions in the waters west of the Big Island of Hawai‘i using bothin situand model data. Catches from Cobb midwater trawls off west Hawai‘i show that reef fish larvae are most numerous in offshore waters deeper than 3,000 m and consist largely of pre-settlement Pomacanthids, Acanthurids and Chaetodontids. Utilizing a Lagrangian larval dispersal model, we were able to replicate the observed shore fish distributions from the trawl data and we identified the 100 m depth strata as the most likely depth of occupancy. Additionally, our model showed that for larval shore fish with a pelagic larval duration longer than 40 days there was no significant change in settlement success in our model. By creating a general additive model (GAM) incorporating lunar phase and angle we were able to explain 67.5% of the variance between modeled andin situAcanthurid abundances. We took steps towards creating a predictive larval distribution model that will greatly aid in understanding the spatiotemporal nature of the larval pool in west Hawai‘i, and the dispersal of larvae throughout the Hawaiian archipelago.
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Jones, Peter E., i Gerard P. Closs. "Interspecific differences in larval production and dispersal in non-migratory galaxiids: implications for metapopulation structure". Marine and Freshwater Research 67, nr 10 (2016): 1479. http://dx.doi.org/10.1071/mf14309.
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Metapopulation structure can strongly influence how species respond to extinction threats. Isolated populations are highly vulnerable to extirpation, whereas interconnected populations are generally more resilient to pressures. In fish with sedentary adults, population connectivity can depend on the movements of early life stages. The present study examined how previously identified interspecific differences in life history affect larval production and dispersal in a species-complex of non-migratory galaxiid fish. Consistent with a priori predictions, ‘fast’ life-history species (high size-relative fecundity, early maturation, small egg size) showed high abundance of potential recruits, whereas the larvae of ‘slow’ life-history species (low size-relative fecundity, late maturation, large egg size) were, on average, between six and nine times less abundant. The species with intermediate traits showed moderate larval abundance compared with other species. The small, poorly swimming larvae of a ‘fast’ life-history species dispersed over large spatial scales (up to over 12km), whereas the larger, better-swimming larvae of a ‘slow’ life-history species showed minimal dispersal (<300m). These findings suggest that the ‘fast’ life-history species are likely to follow a classic source–sink metapopulation structure, whereas ‘slow’ life-history species are more likely to form isolated population structures. The implications for how these species respond to pressures from invasive salmonids, a principal cause of their decline, are discussed.
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Sanvicente-Añorve, Laura, Santiago Aréstegui-Paz Rubio, Elia Lemus-Santana, Eugenia Allende-Arandía i Jorge Zavala-Hidalgo. "Distribution of Hippoidea (Decapoda, Anomura) larvae off Veracruz, southern Gulf of Mexico: inferences about their migration route". Crustaceana 92, nr 5 (3.05.2019): 585–97. http://dx.doi.org/10.1163/15685403-00003889.
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Abstract The distribution and abundance of hippoid zoeal stages offshore Veracruz, southern Gulf of Mexico, and the migration routes of these larvae in the western Atlantic, were analysed. Samples were collected with a Bongo net and larval dispersal was analysed applying the HYCOM hydrodynamical model; particles (virtual larvae) originating from 35 sites were tracked for 77 days. Larvae of Albunea paretii Guérin-Méneville, 1853 were the most abundant, and dispersal simulations indicated that older larvae occurring off Veracruz might originate from Texas. However, a substantial proportion of self-recruitment (7.8%) can occur, mainly due to the seasonal changes in direction of currents over the shelf as well as the high variability in weather conditions. Results also suggest that several generations of A. paretii are needed for the species to reach Veracruz from South America. A hypothetical model regarding the migration routes of A. paretii larvae in the western Atlantic is proposed.
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Price, Amina E., i Paul Humphries. "The role of dispersal and retention in the early life stages of shrimp in a lowland river". Canadian Journal of Fisheries and Aquatic Sciences 67, nr 4 (kwiecień 2010): 720–29. http://dx.doi.org/10.1139/f10-015.
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This study investigated the importance of dispersal and retention processes during early ontogeny for three caridean shrimp species that complete their entire life history in freshwater. Directional traps were used to examine the small-scale movement patterns of shrimp into and out of nursery habitat patches (slackwaters) in a small lowland river in southeastern Australia. Movement patterns provided evidence for two contrasting life history based dispersal and retention strategies. For the two smaller atyid species, Paratya australiensis and Caridina mccullochi , the majority of larvae remained within the slackwater in which they were hatched until the final stage of development, at which point dispersal, either among slackwaters or out of slackwaters to faster-flowing pool and run habitats, occurred. For the larger palaemonid species, Macrobrachium australiense , larvae were hatched into slackwaters and dispersal occurred predominately during the first stage of larval development and then decreased as development progressed. Despite the differences in dispersal strategies among species, movement was mostly associated with a particular larval stage and thus emphasizes the importance of retention during critical developmental periods and of the potential impact that flow alteration could have on these and other species with similar life histories.
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Cox, David L., i Daniel A. Potter. "AERIAL DISPERSAL BEHAVIOR OF LARVAL BAGWORMS, THYRIDOPTERYX EPHEMERAEFORMIS (LEPIDOPTERA: PSYCHIDAE)". Canadian Entomologist 118, nr 6 (czerwiec 1986): 525–36. http://dx.doi.org/10.4039/ent118525-6.
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AbstractSeasonal and daily patterns of ballooning, and behavioral processes involved in aerial dispersal of the bagworm, Thyridopteryx ephemeraeformis (Haworth), were studied on Juniperus virginiana L. in Kentucky. The aerial dispersal period began in mid-May 1983 and lasted ca. 1 month. About 75% of dispersing larvae ballooned after making a bag. Settling velocities were determined for larvae with and without bags and trailing varying lengths of silk; a model was then developed that predicts dispersal distance for a particular wind speed and departure height. Most aerial dispersal is probably short-range. The bag reduced potential dispersal distance, but larvae with bags survived ca. 2 days longer than those without bags when exposed to abiotic factors off of a host. Larvae without bags ballooned mostly in morning, whereas 80% of the larvae dispersing with a bag ballooned in the afternoon. These patterns may be related to the diel periodicity of emergence of neonate larvae from old female bags, and the subsequent behavior of 1st instars prior to dispersal. A large proportion of each cohort emigrates regardless of host condition.
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Bottcher, Claudia, i Paulo S. Oliveira. "Consumption of lipid-rich seed arils improves larval development in a Neotropical primarily carnivorous ant, Odontomachus chelifer (Ponerinae)". Journal of Tropical Ecology 30, nr 6 (29.08.2014): 621–24. http://dx.doi.org/10.1017/s0266467414000479.
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Abstract:Odontomachus chelifer ants collect fallen arillate seeds of Cabralea canjerana (Meliaceae), a bird-dispersed tree of the Atlantic rain forest. In the nest the larvae are fed with the lipid-rich aril, and the viable seed is discarded. Benefits from secondary seed dispersal by ants are well documented for tropical plants, but benefits to ants from consuming vertebrate-dispersed diaspores are uncertain. Twelve captive colonies of O. chelifer were used to investigate the effect of aril consumption on larval development. Treatment colonies were supplemented with 1 g of C. canjerana arils, whereas control colonies were supplemented with 1 g of synthetic diet. Egg and larval production did not differ between experimental colonies after 5 mo. Aril-fed larvae, however, grew 3.5 times larger than those in control colonies. Essential fatty acids in the arils possibly account for improved larval development. Consumption of lipid-rich arils may be critical under scarcity of arthropod prey. Improved larval development through aril consumption confirms that this ant-seed interaction is facultatively mutualistic. This result is meaningful given the predominantly carnivorous diet of O. chelifer, and the generalized nature of ant-seed/fruit interactions in tropical forests. Whether or not benefits to larvae translate into significant gains for ant colonies is uncertain.
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Miller, Michael J., i Katsumi Tsukamoto. "The ecology of oceanic dispersal and survival of anguillid leptocephali". Canadian Journal of Fisheries and Aquatic Sciences 74, nr 6 (czerwiec 2017): 958–71. http://dx.doi.org/10.1139/cjfas-2016-0281.
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Recruitment declines of anguillid eels are difficult to understand because both anthropogenic impacts on juveniles and adults and oceanic changes affecting larval survival or dispersal may be contributing. Anguillid larvae may passively disperse widely from offshore spawning areas but late-stage larvae or glass eels apparently must swim directionally to reach recruitment habitats. Their long larval durations vary among tropical (∼3–4 months) and temperate species (5 months to >1 year). The bodies of anguillid leptocephali are filled with transparent gelatinous material, possibly reducing predation rates and providing an energy reserve for swimming and metamorphosis. Leptocephali feed on marine snow making their first-feeding success linked to primary producers contributing to marine snow production. Alternations between ubiquitous cyanobacteria dominating in low-nutrient conditions and eukaryotic phytoplankton such as diatoms that are important for marine snow production dominating in high-nutrient conditions may influence early-larval survival at first-feeding due to many eggs simultaneously hatching within sympatric spawning areas. Fewer spawning eels resulting from population reductions and variations in early-larval survival may offer some explanations for lower and fluctuating recruitment in recent decades.
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Lechner, Aaron, Hubert Keckeis, Martin Glas, Michael Tritthart, Helmut Habersack, Laurin Andorfer i Paul Humphries. "The influence of discharge, current speed, and development on the downstream dispersal of larval nase (Chondrostoma nasus) in the River Danube". Canadian Journal of Fisheries and Aquatic Sciences 75, nr 2 (luty 2018): 247–59. http://dx.doi.org/10.1139/cjfas-2016-0340.
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We investigated the mode (active versus passive) of larval downstream dispersal and its influencing factors in the nase carp (Chondrostoma nasus). Marked larvae (early and later stages), together with equivalent numbers of passive particles, were released in the main channel of the River Danube (Austria) at different flow (low, high) and current (over-critical, under-critical) conditions. Larvae and particles were recaptured with stationary nets at varying distances from release. We assumed that differences in the spatial dispersal patterns between larvae and particles were due to fish activity. We hypothesized that river discharge, developmental stage, current speed, and distance from release would influence these differences. We found that activity was independent of developmental stage or current speed at release, although activity was higher during low flow conditions. It may be that larvae deliberately enter the current during low flow, because the hydraulic conditions facilitate active dispersal. Furthermore, activity was greatest near the release site. This might be due to an intrinsically greater activity when fish are placed into novel surroundings or a result of rheoreaction. The discharge-dependent dispersal patterns observed represent an important ecological link between flow and recruitment and demonstrate the importance of inshore conditions for the early life stages of fish in large rivers, especially with regard to river modification and restoration schemes.
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Le Goff-Vitry, Marie C., Sandrine Jacquelin i Thierry Comtet. "Towards tracking marine larvae with in situ hybridization". Journal of the Marine Biological Association of the United Kingdom 87, nr 5 (październik 2007): 1077–80. http://dx.doi.org/10.1017/s0025315407057025.
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Marine invertebrate larvae represent a transitory, but nonetheless important component of planktonic communities. Assessing their contribution to plankton diversity has been hindered by numerous methodological difficulties, notably at the identification step. For many sessile invertebrates, planktonic larvae also play a crucial role, as they are their sole dispersal vectors. Understanding connectivity patterns among marine populations is fundamental for managing coastal ecosystems and their associated resources. Indirect approaches, relying on population genetics models, have widely contributed to elucidate population structure and gene flow patterns, but show, in some cases, conflicting results with larval dispersal potential. In an attempt to facilitate surveys of larval distributions and abundances, an in situ hybridization on whole larvae method was tested over a range of marine invertebrate larvae collected from environmental plankton samples. Ribosomal RNA-targeted oligonucleotide probes were used for hybridization, followed by a colorimetric reaction allowing signal detection at the light microscope. Promising results were obtained, showing an unambiguous positive hybridization signal with a eukaryotic (positive) probe, but no signal with a negative probe. Using species-specific probes, the method could be applied to resolve key current questions in marine ecology, addressing both wide and fine scales.
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George, Amy E., Tatiana Garcia, Benjamin H. Stahlschmidt i Duane C. Chapman. "Ontogenetic changes in swimming speed of silver carp, bighead carp, and grass carp larvae: implications for larval dispersal". PeerJ 6 (2.11.2018): e5869. http://dx.doi.org/10.7717/peerj.5869.
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Bighead, silver, and grass carps are invasive in the waterways of central North America, and grass carp reproduction in tributaries of the Great Lakes has now been documented. Questions about recruitment potential motivate a need for accurate models of egg and larval dispersal. Quantitative data on swimming behaviors and capabilities during early ontogeny are needed to improve these dispersal models. We measured ontogenetic changes in routine and maximum swimming speeds of bighead, grass, and silver carp larvae. Daily measurements of routine swimming speed were taken for two weeks post-hatch using a still camera and the LARVEL program, a custom image-analysis software. Larval swimming speed was calculated using larval locations in subsequent image frames and time between images. Using an endurance chamber, we determined the maximum swimming speed of larvae (post-gas bladder inflation) for four to eight weeks post-hatch. For all species, larval swimming speeds showed similar trends with respect to ontogeny: increases in maximum speed, and decreases in routine speed. Maximum speeds of bighead and grass carp larvae were similar and generally faster than silver carp larvae. Routine swimming speeds of all larvae were highest before gas bladder inflation, most likely because gas bladder inflation allowed the fish to maintain position without swimming. Downward vertical velocities of pre-gas bladder inflation fish were faster than upward velocities. Among the three species, grass carp larvae had the highest swimming speeds in the pre-gas bladder inflation period, and the lowest speeds in the post-gas bladder inflation period. Knowledge of swimming capability of these species, along with hydraulic characteristics of a river, enables further refinement of models of embryonic and larval drift.
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Egan, EA, i DT Anderson. "Laval development of the Megabalanine Balanomorph Austromegabalanus nigrescens (Lamarck) (Cirripedia, Balanidae)". Marine and Freshwater Research 38, nr 4 (1987): 511. http://dx.doi.org/10.1071/mf9870511.
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The presence of embryos in the mantle cavity of A. nigrescens was monitored over a 2-year period. A, nigrescens maintains some breeding individuals throughout the year but shows peak breeding during the late autumn, winter and early spring in the vicinity of Sydney, New South Wales, Australia. The larval stages of A. nigrescens are described from larvae reared in the laboratory. A. nigrescens larvae can be easily distinguished from other nauplii described from balanomorphs of New South Wales by their distinctive marginal spines and paired dorsal shield spines. The duration of larval development in A. nigrescens, 13-23 days, is similar to that of other Australian balanids and does not appear to accord with the concept that the distribution of Austromegabalanus species has involved long-range epiplanktonic dispersal. The separation of Austromegabaianus, Notomegabalanus and Megabalanus is supported by larva! differences.
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McGilliard, Carey R., i Ray Hilborn. "Modeling no-take marine reserves in regulated fisheries: assessing the role of larval dispersal". Canadian Journal of Fisheries and Aquatic Sciences 65, nr 11 (listopad 2008): 2509–23. http://dx.doi.org/10.1139/f08-150.
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We explored the effects of larval dispersal distance on the impact of no-take marine reserves (NTMRs) implemented in fisheries with catch regulations. NTMRs exist in many fisheries with harvest regulated by annual catch limits. In these fisheries, catch is taken from outside NTMRs, potentially resulting in reduced abundance outside NTMRs and an overall reduction in catch. We used a spatial model with two life stages (larvae and adults) to evaluate the effects of larval dispersal distance for fisheries managed by a total allowable catch (TAC) and an NTMR. We examined effects of the timing of density-dependent mortality in relation to larval movement. Abundance reached similar values for populations with long and short larval dispersal distances. Catch declined substantially for stocks with short larval dispersal distances. When larval dispersal distances were long, catch declined to values below maximum sustainable yield (MSY), but stabilized. Catch per unit effort (CPUE) declined to 9% of CPUE at MSY for stocks with short distance larval dispersal after the implementation of an NTMR; with long distance larval dispersal, CPUE declined to approximately 50% or less of the CPUE at MSY. The CPUE did not reflect trends in abundance after the implementation of an NTMR.
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Katano, Izumi, Hiromune Mitsuhashi, Hideyuki Doi, Yu Isobe i Tadashi Oishi. "Distribution and drift dispersal dynamics of a caddisfly grazer in response to resource abundance and its ontogeny". Royal Society Open Science 4, nr 1 (styczeń 2017): 160732. http://dx.doi.org/10.1098/rsos.160732.
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Stream grazers have a major impact on food web structure and the productivity of stream ecosystems; however, studies on the longitudinal (upstream versus downstream) and temporal changes in their drift dynamics and resulting distributions remain limited. Here, we investigated the longitudinal and temporal distributions and drift propensity of a trichopteran grazer, the caddisfly, Micrasema quadriloba , during its life cycle in a Japanese stream. The distribution of larvae significantly shifted downstream during the fifth instar larval stage during late winter; with periphyton abundance (i.e. their food source) showing similar shifts downstream. Therefore, our results show that the drift dispersal the caddisfly occurs in response to decline in available food resources (i.e. food-resource scarcity) and an increase in food requirements by growing individuals. Furthermore, our results show that this observed longitudinal shift in larval distribution varies through their life cycle, because the drift dispersal of fifth instar larvae was greater than that of immature larvae. The correlation between periphyton abundance and drift propensity of fourth instar larvae was not statistically significant, whereas that of fifth instar larvae was significantly negative. In conclusion, we detected an ontogenetic shift in drift propensity, which might explain the longitudinal and temporal distributions of this species.
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Rossi, Tullio, Ivan Nagelkerken, Jennifer C. A. Pistevos i Sean D. Connell. "Lost at sea: ocean acidification undermines larval fish orientation via altered hearing and marine soundscape modification". Biology Letters 12, nr 1 (styczeń 2016): 20150937. http://dx.doi.org/10.1098/rsbl.2015.0937.
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The dispersal of larvae and their settlement to suitable habitat is fundamental to the replenishment of marine populations and the communities in which they live. Sound plays an important role in this process because for larvae of various species, it acts as an orientational cue towards suitable settlement habitat. Because marine sounds are largely of biological origin, they not only carry information about the location of potential habitat, but also information about the quality of habitat. While ocean acidification is known to affect a wide range of marine organisms and processes, its effect on marine soundscapes and its reception by navigating oceanic larvae remains unknown. Here, we show that ocean acidification causes a switch in role of present-day soundscapes from attractor to repellent in the auditory preferences in a temperate larval fish. Using natural CO 2 vents as analogues of future ocean conditions, we further reveal that ocean acidification can impact marine soundscapes by profoundly diminishing their biological sound production. An altered soundscape poorer in biological cues indirectly penalizes oceanic larvae at settlement stage because both control and CO 2 -treated fish larvae showed lack of any response to such future soundscapes. These indirect and direct effects of ocean acidification put at risk the complex processes of larval dispersal and settlement.
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Zens, Bernhard, Martin Glas, Michael Tritthart, Helmut Habersack i Hubert Keckeis. "Movement patterns and rheoreaction of larvae of a fluvial specialist (nase, Chondrostoma nasus): the role of active versus passive components of behaviour in dispersal". Canadian Journal of Fisheries and Aquatic Sciences 75, nr 2 (luty 2018): 193–200. http://dx.doi.org/10.1139/cjfas-2016-0276.
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The dispersal of fish larvae in rivers might result from water movement but also from larval behaviour. Although potentially crucial for dispersion, knowledge of the role of behaviour is still fragmentary. This study intends to contribute to the question of how riverine fish larvae drift or move. All dispersal-relevant movement patterns of larvae of a characteristic rheophilic species were analyzed based on the parameters (i) swimming activity, (ii) direction of movement, and (iii) the orientation towards the current vector. Experiments were conducted in a novel flume mesocosm at three different flow scenarios covering the current velocity range of natural habitats. Mean current velocities in these scenarios were under, near, and over the “critical current velocity”, above which fish larvae are not able to constantly hold their position in the water column. Three consecutive larval stages were tested to account for possible ontogenetic shifts in movement behaviour, both during the day and at night. Our results strongly suggest that the assumption of mainly passively drifting larvae has to be refused; in total, 92.6% of all observed movement events were characterized by swimming activity and directed orientation, whereas only 7.4% could be assigned to passive drift. During downstream movement, a significant portion of movement events (57.1%) was attributed to larvae that orientated in an upstream direction and performed active swimming movements.
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Romero, Melissa R., Kimberly M. Walker, Carmen J. Cortez, Yareli Sanchez, Kimberly J. Nelson, Daisha C. Ortega, Serra L. Smick, William J. Hoese i Danielle C. Zacherl. "Larval Diel Vertical Migration of the Marine GastropodKelletia kelletii(Forbes, 1850)". Journal of Marine Biology 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/386575.
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Documenting larval behavior is critical for building an understanding of larval dispersal dynamics and resultant population connectivity. Nocturnal diel vertical migration (DVM), a daily migration towards the surface of the water column at night and downward during the day, can profoundly influence dispersal outcomes. Via laboratory experiments we investigated whether marine gastropodKelletia kelletiilarvae undergo nocturnal DVM and whether the behavior was influenced by the presence of light, ontogeny, and laboratory culturing column height. Larvae exhibited a daily migration pattern consistent with nocturnal diel vertical migration with lower average vertical positioning (ZCM) during day-time hours and higher vertical positioning at night-time hours. ZCM patterns varied throughout ontogeny; larvae became more demersal as they approached competency. There was no effect of column height on larval ZCM. DVM behavior persisted in the absence of light, indicating a possible endogenous rhythm. Findings from field plankton tows corroborated laboratory nocturnal DVM findings; significantly moreK.kelletiiwere found in surface waters at midnight compared to at noon. Unraveling the timing of and the cues initiating DVM behavior inK.kelletiilarvae can help build predictive models of dispersal outcomes for this emerging fishery species.
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Mohd Hanapiah, Muhammad Faiz, Shahbudin Saad i Zuhairi Ahmad. "DISPERSAL PATTERN OF CORAL LARVAE IN KUANTAN COASTAL WATERS, MALAYSIA". Science Heritage Journal 4, nr 1 (14.04.2020): 13–18. http://dx.doi.org/10.26480/gws.01.2020.13.18.
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Understanding source and sink pattern of coral larvae is among the key elements for effective ecosystem management and future habitat restoration. This study examined dispersal pattern of coral larvae among three known inshore reefs (Pulau Ular, Balok Reef and Raja Muda reef) in Kuantan coastal waters by simulating virtual larvae trajectories during spawning event in 2018. Dispersal pathways were modelled and constructed by incorporating biological traits (timing of spawning and pelagic larvae duration) using Langragian particle tracking module integrated with 2-dimensional, hydrodynamic, flexible network model (MIKE 21 FM). Results indicated that Acroporid larvae moved in southward direction throughout dispersal period. Source and sink dynamic suggested that Pulau Ular has high larvae retention (70%) in which most of larvae originated from natal reef. Balok reef was dominant source of larvae for Raja Muda reef. Results also indicated that patches reefs near Raja Muda was ideal sink site for coral larvae and should be prioritized for future ecosystem management action.
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Harding, Gareth C., i Ronald W. Trites. "Dispersal of Homarus americanus Larvae in the Gulf of Maine from Browns Bank". Canadian Journal of Fisheries and Aquatic Sciences 45, nr 3 (1.03.1988): 416–25. http://dx.doi.org/10.1139/f88-050.
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Studies of larval lobster (Homarus americanus) distribution off southwestern Nova Scotia during the summers of 1977 and 1978, were used to estimate an average larval recruitment or production of 1918 and 5284 stage IV lobsters per square kilometre per year inshore and offshore, respectively. Results indicate that the offshore may contribute up to 97% of the larval recruits for the entire southwestern Nova Scotia region. Current patterns and velocities of 3–16 cm∙s−1 were estimated from surface drifter returns within the Gulf of Maine. Limits of larval dispersion are estimated from surface currents in the region and the physiological and ecological traits of the larval lobster. Offshore lobsters could make an important contribution to recruitment not only off southwestern Nova Scotia but in the entire eastern sector of the Gulf of Maine to Casco Bay. Larval dispersal provides another line of evidence that the Gulf of Maine area represents one lobster recruitment center. Our results are consistent with the idea that ontogenic seasonal migration of female lobsters has evolved to locate planktotrophic larvae in warmer shoal areas where growth and survival is optimal and from which ocean currents subsequently disperse a large portion of these larvae to settle over highly productive juvenile grounds.
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Hodin, Jason, Matthew C. Ferner i Brian Gaylord. "Choosing the right home: settlement responses by larvae of six sea urchin species align with hydrodynamic traits of their contrasting adult habitats". Zoological Journal of the Linnean Society 190, nr 2 (23.01.2020): 737–56. http://dx.doi.org/10.1093/zoolinnean/zlz149.
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Abstract Ocean organisms as diverse as seaweeds and sea cucumbers exhibit life cycles in which dispersal occurs primarily via microscopic larvae or spores, with adults exhibiting limited or even no dispersal. In benthic animals, the larval stage concludes with irreversible settlement into the benthos. The decision of where and when to settle is thus one of substantial import. Prior work has shown that settlement in two shoreline echinoids (a sea urchin and a sand dollar) is unexpectedly sensitive to an environmental feature (intense fluid turbulence) that can be considered as a signal to larvae of their arrival in the neighbourhood of the hydrodynamically energetic habitats in which these taxa live as adults. Here, we used a comparative approach to explore the evolution of turbulence responsiveness in late-stage echinoid larvae. We examined three pairs of closely related sea urchins that differ in the energetic exposure of their adult habitats and found that larval responsiveness to turbulence was more pronounced in urchins that settle in more hydrodynamically exposed locations. These results raise the possibility that evolutionary differences in larval responsiveness to environmental indicators of appropriate adult habitat might reinforce or even provide a mechanism for vicariance in the ocean.
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Ruttenberg, Benjamin I., Scott L. Hamilton i Robert R. Warner. "Spatial and temporal variation in the natal otolith chemistry of a Hawaiian reef fish: prospects for measuring population connectivity". Canadian Journal of Fisheries and Aquatic Sciences 65, nr 6 (czerwiec 2008): 1181–92. http://dx.doi.org/10.1139/f08-052.
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One of the most compelling unanswered questions in marine ecology is the extent to which local populations are connected via larval exchange. Recent work has suggested that variation in the chemistry of otoliths (earstones) of fishes may function as a natural tag, potentially allowing investigators to determine sources of individual larvae and estimate larval connectivity. We analyzed the spatial and temporal variation in natal otolith chemistry of a benthic-spawning reef fish from the Hawaiian Islands. We found no consistent chemical variation at the largest scale (>100 km, among islands), but found significant variation at moderate scales (sites within islands, tens of kilometres) and small scales (clutches within sites), and chemistry of otoliths was not stable between years. These results imply that we may be able to use otolith chemistry to track larval dispersal only if the scales of dispersal match those of variation in natal otolith chemistry, and that separate natal otolith collections may be needed to track different cohorts of larvae. Finally, we found that elemental composition of recruit cores often did not match that of natal otoliths, suggesting that additional methodological development is required before we can effectively apply methods in otolith chemistry to the study of larval dispersal.