This paper presents results from a four year tagging effort on Atlantic herring (Clupea harengus) in the waters off the east coast of the United States. This study was designed to describe seasonal movements and evaluate new live capture methods for mobile gear using an aquarium codend. A total of 85 561 Atlantic herring were tagged and released in two strata; the Gulf of Maine during the summer feeding/spawning period and Southern New England during the winter feeding period. The return rate, adjusted for reporting, was 2.6% and the patterns of returns largely reflected results from previous tagging studies in the US and Canada. The two main contributions of this work to the established body of herring tagging literature are: (1) the identification of current seasonal movements, including the migration of Atlantic herring from Southern New England in the winter to Nova Scotia in the summer, and (2) the implementation of a capture technique for midwater trawl gear and the ability this provided the researchers to successfully tag Atlantic herring on their winter feeding grounds as far south as Cape May, NJ.
{"title":"Seasonal Movements of Atlantic Herring (Clupea harengus): Results From a Four Year Tagging Study Conducted in the Gulf of Maine and Southern New England","authors":"J. K. Kanwit, D. Libby","doi":"10.2960/J.V40.M577","DOIUrl":"https://doi.org/10.2960/J.V40.M577","url":null,"abstract":"This paper presents results from a four year tagging effort on Atlantic herring (Clupea harengus) in the waters off the east coast of the United States. This study was designed to describe seasonal movements and evaluate new live capture methods for mobile gear using an aquarium codend. A total of 85 561 Atlantic herring were tagged and released in two strata; the Gulf of Maine during the summer feeding/spawning period and Southern New England during the winter feeding period. The return rate, adjusted for reporting, was 2.6% and the patterns of returns largely reflected results from previous tagging studies in the US and Canada. The two main contributions of this work to the established body of herring tagging literature are: (1) the identification of current seasonal movements, including the migration of Atlantic herring from Southern New England in the winter to Nova Scotia in the summer, and (2) the implementation of a capture technique for midwater trawl gear and the ability this provided the researchers to successfully tag Atlantic herring on their winter feeding grounds as far south as Cape May, NJ.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Age and growth were determined from otoliths for 181 juvenile bluefish (Pomatomus saltatrix ), collected using a variety of gear in northeast Florida during 2003 and 2005. Three distinct cohorts were identified recruiting to the near shore waters during spring, summer and autumn. Growth rates were high regardless of cohort or season. To compare pre- and post-recruitment growth rates, models were fit to individual growth trajectories using change point analysis. Post-estuarine growth rates were generally higher. Growth rates and hatching times were within the range of those obtained in other bluefish studies conducted at higher latitudes. As this is the only area where winter recruitment of bluefish has been observed, coastal Florida habitats may be essential for the bluefish stock and will need to be carefully monitored in future studies.
{"title":"Cohort-specific Winter Growth Rates of YOY Bluefish, Pomatomus saltatrix, in Northeast Florida Estuaries: Implications for Recruitment","authors":"J. Murt, F. Juanes","doi":"10.2960/J.V41.M629","DOIUrl":"https://doi.org/10.2960/J.V41.M629","url":null,"abstract":"Age and growth were determined from otoliths for 181 juvenile bluefish (Pomatomus saltatrix ), collected using a variety of gear in northeast Florida during 2003 and 2005. Three distinct cohorts were identified recruiting to the near shore waters during spring, summer and autumn. Growth rates were high regardless of cohort or season. To compare pre- and post-recruitment growth rates, models were fit to individual growth trajectories using change point analysis. Post-estuarine growth rates were generally higher. Growth rates and hatching times were within the range of those obtained in other bluefish studies conducted at higher latitudes. As this is the only area where winter recruitment of bluefish has been observed, coastal Florida habitats may be essential for the bluefish stock and will need to be carefully monitored in future studies.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Köster, M. Vinther, B. MacKenzie, M. Eero, M. Plikshs
The decline of the Eastern Baltic cod (Gadus morhua) stock from highest to lowest stock levels on record throughout the 1980s and early 1990s was caused by a combination of recruitment failure and increasing fishing pressure at declining stock sizes. The processes driving the reproductive success are largely understood, but the consequences of these changes for fisheries management are far less evident. This includes doubts about the adequacy of the biological reference points presently used to advise on the stock status, and the need of their revision given that environmental changes have affected stock productivity. Long-term projections suggest that under adverse environmental conditions for reproduction, harvesting at fishing mortality determined as precautionary may not lead to a recovery of the stock to a biomass level considered precautionary. Thus, a revision of either the limit fishing mortality or the limit biomass reference point is indicated. However, an accepted methodology to determine these reference points in situations of changing stock productivity or system carrying capacity does not exist. Environmental conditions affecting recruitment matter not only for the determination of limit reference points, but according to long-term simulations also for target fishing mortalities, being central parts of harvest control rules in several management plans.
{"title":"Environmental effects on recruitment and implications for biological reference points of Eastern Baltic cod (Gadus morhua)","authors":"F. Köster, M. Vinther, B. MacKenzie, M. Eero, M. Plikshs","doi":"10.2960/J.V41.M636","DOIUrl":"https://doi.org/10.2960/J.V41.M636","url":null,"abstract":"The decline of the Eastern Baltic cod (Gadus morhua) stock from highest to lowest stock levels on record throughout the 1980s and early 1990s was caused by a combination of recruitment failure and increasing fishing pressure at declining stock sizes. The processes driving the reproductive success are largely understood, but the consequences of these changes for fisheries management are far less evident. This includes doubts about the adequacy of the biological reference points presently used to advise on the stock status, and the need of their revision given that environmental changes have affected stock productivity. Long-term projections suggest that under adverse environmental conditions for reproduction, harvesting at fishing mortality determined as precautionary may not lead to a recovery of the stock to a biomass level considered precautionary. Thus, a revision of either the limit fishing mortality or the limit biomass reference point is indicated. However, an accepted methodology to determine these reference points in situations of changing stock productivity or system carrying capacity does not exist. Environmental conditions affecting recruitment matter not only for the determination of limit reference points, but according to long-term simulations also for target fishing mortalities, being central parts of harvest control rules in several management plans.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A mark-recapture experiment was conducted on the northern stock of black sea bass (Centropristis striata) which ranges from southern portions of the Gulf of Maine to Cape Hatteras, North Carolina. Tag recovery data from traditional tags indicate that extensive seasonal movements occur and are not homogeneous throughout the stock. During summer months fish throughout the stock remain stationary in coastal areas with very little mixing among adjacent areas. In autumn, offshore migration toward the edge of the continental shelf begins in the north and progresses southward. During the offshore overwintering period, intermixing of fish from various inshore areas is more frequent. Recaptures following spring inshore migrations demonstrate a high degree of site-fidelity with occasional straying to adjacent areas. Archival data tags suggest that offshore migration coincides with declining water temperature.
{"title":"Seasonal Distribution and Movement of Black Sea Bass (Centropristis striata) in the Northwest Atlantic as Determined from a Mark-Recapture Experiment","authors":"Joshua Moser, G. Shepherd","doi":"10.2960/J.V40.M638","DOIUrl":"https://doi.org/10.2960/J.V40.M638","url":null,"abstract":"A mark-recapture experiment was conducted on the northern stock of black sea bass (Centropristis striata) which ranges from southern portions of the Gulf of Maine to Cape Hatteras, North Carolina. Tag recovery data from traditional tags indicate that extensive seasonal movements occur and are not homogeneous throughout the stock. During summer months fish throughout the stock remain stationary in coastal areas with very little mixing among adjacent areas. In autumn, offshore migration toward the edge of the continental shelf begins in the north and progresses southward. During the offshore overwintering period, intermixing of fish from various inshore areas is more frequent. Recaptures following spring inshore migrations demonstrate a high degree of site-fidelity with occasional straying to adjacent areas. Archival data tags suggest that offshore migration coincides with declining water temperature.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69255726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Climatic and ecosystem changes in the transition region between the subarctic Oyashio and the subtropical Kuroshio Extension fronts may be the key to understanding recruitment variability of small pelagic fish populations in the Pacific waters off Japan. The transition region is characterized by complex oceanographic structure with the meandering fronts, eddies and streamers creating large spatial and temporal variability in the environment. Juveniles of small pelagic fishes such as Japanese sardine (Sardinops melanostictus), Pacific saury (Cololabis saira), and Japanese anchovy (Engraulis japonicus) migrate from the subtropical Kuroshio Current area to the subarctic Oyashio Current area across the transition region. A precipitous decline in number of age 0 recruits of Japanese sardine after the end of 1980s appears to be related to the extremely high mortality rate of young-of-the-year fish in the transition region. In contrast, populations of Pacific saury and Japanese anchovy increased after 1988. These synchronous changes in populations seem to be associated with the weakening of the Aleutian Low Pressure in the North Pacific and weakening of the Oyashio Current in winter, and a sea surface temperature (SST) rise in the Kuroshio-Oyashio transition region in spring. The contrasting responses of the fish populations to the SST rise can be explained by different temperature preference in terms of growth rate in larval and early juvenile stages; cool temperatures are preferred by sardine and warm temperatures are preferred by saury and anchovy.
{"title":"Recruitment Variability of Small Pelagic Fish Populations in the Kuroshio-Oyashio Transition Region of the Western North Pacific","authors":"Yoshirô Watanabe","doi":"10.2960/J.V41.M635","DOIUrl":"https://doi.org/10.2960/J.V41.M635","url":null,"abstract":"Climatic and ecosystem changes in the transition region between the subarctic Oyashio and the subtropical Kuroshio Extension fronts may be the key to understanding recruitment variability of small pelagic fish populations in the Pacific waters off Japan. The transition region is characterized by complex oceanographic structure with the meandering fronts, eddies and streamers creating large spatial and temporal variability in the environment. Juveniles of small pelagic fishes such as Japanese sardine (Sardinops melanostictus), Pacific saury (Cololabis saira), and Japanese anchovy (Engraulis japonicus) migrate from the subtropical Kuroshio Current area to the subarctic Oyashio Current area across the transition region. A precipitous decline in number of age 0 recruits of Japanese sardine after the end of 1980s appears to be related to the extremely high mortality rate of young-of-the-year fish in the transition region. In contrast, populations of Pacific saury and Japanese anchovy increased after 1988. These synchronous changes in populations seem to be associated with the weakening of the Aleutian Low Pressure in the North Pacific and weakening of the Oyashio Current in winter, and a sea surface temperature (SST) rise in the Kuroshio-Oyashio transition region in spring. The contrasting responses of the fish populations to the SST rise can be explained by different temperature preference in terms of growth rate in larval and early juvenile stages; cool temperatures are preferred by sardine and warm temperatures are preferred by saury and anchovy.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
White hake (Urophycis tenuis) is a temperate demersal fish species distributed in the northwest Atlantic. On the Grand Bank, it is concentrated mainly to the southwest where water temperatures are warmest. Survey data indicate that mature adult females aggregate on the southwest (SW) Grand Bank slope in spring and first-year juveniles settle on the southern, shallow Grand Bank in autumn. Dispersion patterns and survival potential of eggs, larvae and juveniles were investigated with respect to the effects of location (horizontal and vertical) and timing (monthly) of spawning under monthly-mean circulation fields, M2 tidal currents and associated turbulent mixing computed from a three-dimensional regional ocean circulation model. The results indicate that releases below the surface Ekman layer and in late spring have the highest chances for juveniles to settle in the southern Grand Bank nursery area in autumn. On an interannual scale, the strong recruitment of the 1999 yearclass has been used as an example to examine the potential linkage between recruitment and the strength of the Labrador Current. A weak along-slope current and strong on-bank flow contributed to the strong recruitment of the 1999 year-class.
{"title":"Dispersion of Eggs, Larvae and Pelagic Juveniles of White Hake (Urophycis tenuis) in Relation to Ocean Currents of the Grand Bank: A Modelling Approach","authors":"G. Han, D. Kulka","doi":"10.2960/J.V41.M627","DOIUrl":"https://doi.org/10.2960/J.V41.M627","url":null,"abstract":"White hake (Urophycis tenuis) is a temperate demersal fish species distributed in the northwest Atlantic. On the Grand Bank, it is concentrated mainly to the southwest where water temperatures are warmest. Survey data indicate that mature adult females aggregate on the southwest (SW) Grand Bank slope in spring and first-year juveniles settle on the southern, shallow Grand Bank in autumn. Dispersion patterns and survival potential of eggs, larvae and juveniles were investigated with respect to the effects of location (horizontal and vertical) and timing (monthly) of spawning under monthly-mean circulation fields, M2 tidal currents and associated turbulent mixing computed from a three-dimensional regional ocean circulation model. The results indicate that releases below the surface Ekman layer and in late spring have the highest chances for juveniles to settle in the southern Grand Bank nursery area in autumn. On an interannual scale, the strong recruitment of the 1999 yearclass has been used as an example to examine the potential linkage between recruitment and the strength of the Labrador Current. A weak along-slope current and strong on-bank flow contributed to the strong recruitment of the 1999 year-class.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this study was to estimate and discuss the variation in the 50% ovigerous length (OL50) of female red king crab (Paralithodes camtschaticus) sampled from three Norwegian fjords in the Barents Sea. Egg status from 19 872 females were collected and analysed from 1994–2007. Females were defined as sexually mature based on the observed presence of eggs or past presence of eggs (egg remnants). Differences in the OL50 value according to the sample year and fjord were illustrated, but were to a large degree caused by large numbers of young females representing strong year-classes that passed through the size distribution over time. In Varangerfjorden, the mean OL50 was 108.9 ± 0.2 mm CL for a 14 year sampling period. The mean OL50 estimates were 108.7 ± 0.3 mm and 111.8 ± 0.5 mm CL for a nine and six year sampling period in Tanafjorden and Laksefjorden, respectively. Russian scientists successfully introduced the red king crab into the Barents Sea during 1960–1969 with the aim of establishing a fishery. The red king crab stock has since grown and extended its distribution. Norway started fishing red king crab in 1994, and the harvest rate has increased gradually since the onset of the commercial fishing. Female red king crab appears to mature at a larger size in the Barents Sea than those found in its native areas.
本研究的目的是估计和讨论来自挪威巴伦支海三个峡湾的雌性红王蟹(Paralithodes camtschaticus) 50%卵生长度(OL50)的变化。1994-2007年收集并分析了19 872只雌蚊的卵子状况。根据观察到的卵的存在或过去存在的卵(卵残余)，将雌性定义为性成熟。OL50值在样本年份和峡湾之间存在差异，但这在很大程度上是由于大量年轻雌性代表了强大的年份类别，它们随着时间的推移通过了大小分布。在Varangerfjorden, 14年采样期的平均OL50为108.9±0.2 mm CL。在9年和6年的采样期内，Tanafjorden和Laksefjorden的平均OL50估计分别为108.7±0.3 mm和111.8±0.5 mm CL。1960年至1969年期间，俄罗斯科学家成功地将红帝王蟹引入巴伦支海，目的是建立渔业。此后，红帝王蟹的数量不断增长，并扩大了其分布范围。挪威于1994年开始捕捞红帝王蟹，自商业捕捞开始以来，收获率逐渐提高。雌性红帝王蟹在巴伦支海的成熟尺寸似乎比在其原生地区发现的要大。
{"title":"Size at Sexual Maturity in the Female Red King Crab (Paralithodes camtschaticus) in a Newly Settled Population in the Barents Sea, Norway","authors":"A. M. Hjelset, J. H. Sundit, E. M. Nilssen","doi":"10.2960/J.V41.M633","DOIUrl":"https://doi.org/10.2960/J.V41.M633","url":null,"abstract":"The aim of this study was to estimate and discuss the variation in the 50% ovigerous length (OL50) of female red king crab (Paralithodes camtschaticus) sampled from three Norwegian fjords in the Barents Sea. Egg status from 19 872 females were collected and analysed from 1994–2007. Females were defined as sexually mature based on the observed presence of eggs or past presence of eggs (egg remnants). Differences in the OL50 value according to the sample year and fjord were illustrated, but were to a large degree caused by large numbers of young females representing strong year-classes that passed through the size distribution over time. In Varangerfjorden, the mean OL50 was 108.9 ± 0.2 mm CL for a 14 year sampling period. The mean OL50 estimates were 108.7 ± 0.3 mm and 111.8 ± 0.5 mm CL for a nine and six year sampling period in Tanafjorden and Laksefjorden, respectively. Russian scientists successfully introduced the red king crab into the Barents Sea during 1960–1969 with the aim of establishing a fishery. The red king crab stock has since grown and extended its distribution. Norway started fishing red king crab in 1994, and the harvest rate has increased gradually since the onset of the commercial fishing. Female red king crab appears to mature at a larger size in the Barents Sea than those found in its native areas.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sperm storage in female crabs is assumed to provide resiliency in population reproductive potential for exploited crab stocks with male-only harvest restrictions. However, contrasting results have been reported for the reproductive success of female Tanner crab (Chionoecetes bairdi) relying on stored sperm for fertilization. Ovigerous multiparous female C. bairdi were collected and held in the laboratory in the absence of males from hatching to extrusion or collected after hatching and extrusion of a subsequent clutch in situ in Glacier Bay, Alaska. Females were classified into two groups based on extrusion site, LE (laboratory) or FE (field). Mating of multiparous females was important for maintenance of reproductive potential as sperm reserves were likely insufficient for full fertilization of an additional egg clutch from stored sperm in 44% of LE females. High incidence of fresh grasping marks for FE (97%) versus LE (4%) females and significantly higher sperm reserves indicated that most FE females were likely to have recently mated. Mean postextrusion spermathecal load and sperm cell counts increased significantly from 0.21 to 0.44 g and 2.00 × 107 to 9.35 × 107, respectively, between LE and FE females (p 99%), with similar fecundity. Characterization of spatiotemporal trends in mating status, sperm reserves and egg production in C. bairdi may be valuable for understanding natural variability in reproduction and possible fishery effects on population reproductive potential.
{"title":"Reproductive Success of Multiparous Female Tanner Crab (Chionoecetes bairdi) Fertilizing Eggs With or Without Recent Access to Males","authors":"J. Webb","doi":"10.2960/J.V41.M611","DOIUrl":"https://doi.org/10.2960/J.V41.M611","url":null,"abstract":"Sperm storage in female crabs is assumed to provide resiliency in population reproductive potential for exploited crab stocks with male-only harvest restrictions. However, contrasting results have been reported for the reproductive success of female Tanner crab (Chionoecetes bairdi) relying on stored sperm for fertilization. Ovigerous multiparous female C. bairdi were collected and held in the laboratory in the absence of males from hatching to extrusion or collected after hatching and extrusion of a subsequent clutch in situ in Glacier Bay, Alaska. Females were classified into two groups based on extrusion site, LE (laboratory) or FE (field). Mating of multiparous females was important for maintenance of reproductive potential as sperm reserves were likely insufficient for full fertilization of an additional egg clutch from stored sperm in 44% of LE females. High incidence of fresh grasping marks for FE (97%) versus LE (4%) females and significantly higher sperm reserves indicated that most FE females were likely to have recently mated. Mean postextrusion spermathecal load and sperm cell counts increased significantly from 0.21 to 0.44 g and 2.00 × 107 to 9.35 × 107, respectively, between LE and FE females (p 99%), with similar fecundity. Characterization of spatiotemporal trends in mating status, sperm reserves and egg production in C. bairdi may be valuable for understanding natural variability in reproduction and possible fishery effects on population reproductive potential.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69255824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Size-selective fishing mortality may induce evolutionary changes to smaller size at maturation in fish stocks. Marine reserves can be a useful management tool dealing with the ecological and evolutionary effects of fisheries. We examine the effect of size-selective harvesting and the implementation of marine reserves on the evolution of size at maturation using individual-based models. The mobility of individual fish is included as an evolving trait to account for possible behavioural changes in dispersal patterns. The evolutionary change in maturation size can be prevented inside the reserve, leading to higher abundance there. The results show the benefit of reserves on yield, especially at intermediate movement probability. Reserve implementation may cause mobility of individuals to decrease, increasing the possibility of local adaptation in maturation strategy. Evolutionary changes in mobility through marine reserve implementation increase the protection from evolution to small maturation size within the reserve, but may lead to overestimation of yield benefits due to reduced spill-over.
{"title":"An Individual-based Model for Reviewing Marine Reserves in the Light of Fisheries-induced Evolution in Mobility and Size at Maturation","authors":"T. Miethe, J. Pitchford, C. Dytham","doi":"10.2960/J.V41.M624","DOIUrl":"https://doi.org/10.2960/J.V41.M624","url":null,"abstract":"Size-selective fishing mortality may induce evolutionary changes to smaller size at maturation in fish stocks. Marine reserves can be a useful management tool dealing with the ecological and evolutionary effects of fisheries. We examine the effect of size-selective harvesting and the implementation of marine reserves on the evolution of size at maturation using individual-based models. The mobility of individual fish is included as an evolving trait to account for possible behavioural changes in dispersal patterns. The evolutionary change in maturation size can be prevented inside the reserve, leading to higher abundance there. The results show the benefit of reserves on yield, especially at intermediate movement probability. Reserve implementation may cause mobility of individuals to decrease, increasing the possibility of local adaptation in maturation strategy. Evolutionary changes in mobility through marine reserve implementation increase the protection from evolution to small maturation size within the reserve, but may lead to overestimation of yield benefits due to reduced spill-over.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2009-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Greenland halibut (Reinhardtius hippoglossoides) supports one of the major groundfish fisheries of the Northwest Atlantic and its biological stock structure is an important management concern. Using nuclear DNA microsatellite markers and a combination of summary statistics and Bayesian inference, we identified two distinct stocks, both represented within the Baffin Island–West Greenland complex and in the Gulf of St. Lawrence. While a North-South pattern of genetic structure was not supported, our data suggest East-West differentiation within Baffin Bay and Davis Strait. Genetic distances between samples were not correlated with geographic distances, and some degree of intermingling of the two stocks within the same assemblages was detected. Our preliminary results warrant further investigation of the observed patterns with the support of an intensive sampling scheme.
{"title":"Initial Genetic Evidence of Population Structure of Greenland Halibut (Reinhardtius hippoglossoides) in the Northwest Atlantic","authors":"C. Pomilla, Melissa Lindsay","doi":"10.2960/J.V40.M637","DOIUrl":"https://doi.org/10.2960/J.V40.M637","url":null,"abstract":"Greenland halibut (Reinhardtius hippoglossoides) supports one of the major groundfish fisheries of the Northwest Atlantic and its biological stock structure is an important management concern. Using nuclear DNA microsatellite markers and a combination of summary statistics and Bayesian inference, we identified two distinct stocks, both represented within the Baffin Island–West Greenland complex and in the Gulf of St. Lawrence. While a North-South pattern of genetic structure was not supported, our data suggest East-West differentiation within Baffin Bay and Davis Strait. Genetic distances between samples were not correlated with geographic distances, and some degree of intermingling of the two stocks within the same assemblages was detected. Our preliminary results warrant further investigation of the observed patterns with the support of an intensive sampling scheme.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2008-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69255713","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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