Ocean acidification resulting from the global increase in atmospheric CO 2 concentration is emerging as a threat to marine species, including crustaceans. Fisheries involving the American lobster (Homarus americanus) are economically important in eastern Canada and United States. Based on ocean pH levels predicted for 2100, this study examined the effects of reduced seawater pH on the growth (carapace length) and development (time to molt) of American lobster larvae throughout stages I–III until reaching stage IV (postlarvae). Each stage is reached after a corresponding molt. Larvae were reared from stage I in either acidified (pH = 7.7) or control (pH = 8.1) seawater. Organisms in acidified seawater exhibited a significantly shorter carapace length than those in control seawater after every molt. Larvae in acidified seawater also took significantly more time to reach each molt than control larvae. In nature, slowed progress through larval molts could result in greater time in the water column, where larvae are vulnerable to pelagic predators, potentially leading to reduced benthic recruitment. Evidence was also found of reduced survival when reaching the last stage under acidified conditions. Thus, from the perspective of larval ecology, it is possible that future ocean acidification may harm this important marine resource.
{"title":"Ocean Acidification Decreases Growth and Development in American Lobster (Homarus americanus) Larvae","authors":"E. Keppel, R. Scrosati, S. Courtenay","doi":"10.2960/J.V44.M683","DOIUrl":"https://doi.org/10.2960/J.V44.M683","url":null,"abstract":"Ocean acidification resulting from the global increase in atmospheric CO 2 concentration is emerging as a threat to marine species, including crustaceans. Fisheries involving the American lobster (Homarus americanus) are economically important in eastern Canada and United States. Based on ocean pH levels predicted for 2100, this study examined the effects of reduced seawater pH on the growth (carapace length) and development (time to molt) of American lobster larvae throughout stages I–III until reaching stage IV (postlarvae). Each stage is reached after a corresponding molt. Larvae were reared from stage I in either acidified (pH = 7.7) or control (pH = 8.1) seawater. Organisms in acidified seawater exhibited a significantly shorter carapace length than those in control seawater after every molt. Larvae in acidified seawater also took significantly more time to reach each molt than control larvae. In nature, slowed progress through larval molts could result in greater time in the water column, where larvae are vulnerable to pelagic predators, potentially leading to reduced benthic recruitment. Evidence was also found of reduced survival when reaching the last stage under acidified conditions. Thus, from the perspective of larval ecology, it is possible that future ocean acidification may harm this important marine resource.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69257124","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 demersal fish fauna at 900–1800 m depths off Nova Scotia, Canada, is described using data from exploratory bottom trawl surveys conducted in November 1994 and March 1995 by a commercial fishing trawler. Approximately 25 metric tons (39 000 specimens) of demersal fish belonging to at least 82 species were caught, 30% of which had not previously been recorded from the area. However, more than half the catch consisted of the two species Centroscyllium fabricii (black dogfish) and Coryphaenoides rupestris (roundnose grenadier). Catches were higher in the shallower depth strata fished and cluster analysis showed that depth was the primary factor determining species composition of catches. It is suspected, however, that the vessel fished less effectively at depths greater than about 1500 m, contributing to the reduction in catch quantities at these depths. The importance in catches of large bodied species, particularly Chimaeriformes and sharks, contrasts with results from surveys in adjacent areas. This likely reflects the greater fishing power of the vessel/gear used in present surveys rather than real differences in faunal composition. Catches of mesopelagic species during these surveys, and during an earlier deepwater trawling survey in this area, are also described.
{"title":"Demersal fish fauna of the continental slope off Nova Scotia, Canada, based on exploratory bottom trawl surveys in 199495","authors":"R. G. Halliday, L. Guelpen, D. Themelis","doi":"10.2960/J.V44.M681","DOIUrl":"https://doi.org/10.2960/J.V44.M681","url":null,"abstract":"The demersal fish fauna at 900–1800 m depths off Nova Scotia, Canada, is described using data from exploratory bottom trawl surveys conducted in November 1994 and March 1995 by a commercial fishing trawler. Approximately 25 metric tons (39 000 specimens) of demersal fish belonging to at least 82 species were caught, 30% of which had not previously been recorded from the area. However, more than half the catch consisted of the two species Centroscyllium fabricii (black dogfish) and Coryphaenoides rupestris (roundnose grenadier). Catches were higher in the shallower depth strata fished and cluster analysis showed that depth was the primary factor determining species composition of catches. It is suspected, however, that the vessel fished less effectively at depths greater than about 1500 m, contributing to the reduction in catch quantities at these depths. The importance in catches of large bodied species, particularly Chimaeriformes and sharks, contrasts with results from surveys in adjacent areas. This likely reflects the greater fishing power of the vessel/gear used in present surveys rather than real differences in faunal composition. Catches of mesopelagic species during these surveys, and during an earlier deepwater trawling survey in this area, are also described.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256920","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}
Fishing trials with bottom fixed gears (primarily gillnets but also shrimp and crab traps and longlines) were conducted on the continental slope off Nova Scotia in August 1991. Fishing was conducted at several depths between 500 and 2800 m in two areas, one on the open slope south of Emerald Bank and the other at the mouth of The Gully, a large canyon. Catches by gillnets accounted for about 90% of the total and were predominated by deepwater chimaera (Hydrolagus affinis), black dogfish (Centroscyllium fabricii) and Portuguese shark (Centroscymnus coelolepis). The most frequently caught species in traps were snubnose eel (Simenchelys parasitica) and abyssal grenadier (Coryphaenoides armatus). Variations in catches by depth and area are described, and comparisons are made with catches from otter trawl surveys at similar depths with regard to the most prominent species caught and their size compositions.
{"title":"Demersal fishes caught with bottom gillnets and baited gears at 500-2800m on the continental slope off Nova Scotia, Canada","authors":"R. G. Halliday, D. Themelis, W. Hickey","doi":"10.2960/J.V44.M675","DOIUrl":"https://doi.org/10.2960/J.V44.M675","url":null,"abstract":"Fishing trials with bottom fixed gears (primarily gillnets but also shrimp and crab traps and longlines) were conducted on the continental slope off Nova Scotia in August 1991. Fishing was conducted at several depths between 500 and 2800 m in two areas, one on the open slope south of Emerald Bank and the other at the mouth of The Gully, a large canyon. Catches by gillnets accounted for about 90% of the total and were predominated by deepwater chimaera (Hydrolagus affinis), black dogfish (Centroscyllium fabricii) and Portuguese shark (Centroscymnus coelolepis). The most frequently caught species in traps were snubnose eel (Simenchelys parasitica) and abyssal grenadier (Coryphaenoides armatus). Variations in catches by depth and area are described, and comparisons are made with catches from otter trawl surveys at similar depths with regard to the most prominent species caught and their size compositions.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256860","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}
R. Rideout, M. Morgan, Y. Lambert, Alejandro M. Cohen, J. Banoub, Oceans Canada, M. Treble
Abstract Histological data presented here supports the notion of an uncommon oocyte development pattern for Greenland halibut, with two simultaneous groups of developing oocytes in the ovary, the larger group developing for the upcoming spawning season and the smaller group developing for next year ( i.e. the duration of vitellogenesis is > 1 yr.). We analyzed blood samples collected from wild fish as well as fish that were part of the first documented study of Greenland halibut reproductive development in captivity in order to explore the annual cycle of vitellogenin production for this species. Despite the unusual oocyte development strategy there were no obvious differences in seasonal vitellogenin profiles versus fish with more traditional oocyte development strategies. Blood plasma vitellogenin levels generally peaked prior to or during spawning for those fish that successfully spawned, while patterns were highly variable for fish that did not spawn. Maximum plasma vitellogenin levels observed were 25 mg/ml and within the range of values observed for other fish species. Continued refinements in husbandry and experimental protocols for the study of Greenland halibut in captivity will provide a valuable tool for examining aspects of the species’ biology that are difficult to ascertain based on sampling of only wild fish.
{"title":"Oocyte development and vitellogenin production in Northwest Atlantic Greenland halibut Reinhardtius hippoglossoides","authors":"R. Rideout, M. Morgan, Y. Lambert, Alejandro M. Cohen, J. Banoub, Oceans Canada, M. Treble","doi":"10.2960/J.V44.M679","DOIUrl":"https://doi.org/10.2960/J.V44.M679","url":null,"abstract":"Abstract Histological data presented here supports the notion of an uncommon oocyte development pattern for Greenland halibut, with two simultaneous groups of developing oocytes in the ovary, the larger group developing for the upcoming spawning season and the smaller group developing for next year ( i.e. the duration of vitellogenesis is > 1 yr.). We analyzed blood samples collected from wild fish as well as fish that were part of the first documented study of Greenland halibut reproductive development in captivity in order to explore the annual cycle of vitellogenin production for this species. Despite the unusual oocyte development strategy there were no obvious differences in seasonal vitellogenin profiles versus fish with more traditional oocyte development strategies. Blood plasma vitellogenin levels generally peaked prior to or during spawning for those fish that successfully spawned, while patterns were highly variable for fish that did not spawn. Maximum plasma vitellogenin levels observed were 25 mg/ml and within the range of values observed for other fish species. Continued refinements in husbandry and experimental protocols for the study of Greenland halibut in captivity will provide a valuable tool for examining aspects of the species’ biology that are difficult to ascertain based on sampling of only wild fish.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256873","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}
B. Herrmann, M. Sistiaga, K. N. Nielsen, R. Larsen
The majority of trawl selectivity studies for the three redfish species of particular commercial importance in North Atlantic fisheries: Sebastes marinus, Sebastes mentella and Sebastes fasciatus, are based on data collected from diamond mesh codends with mesh sizes ranging from 88 mm to 147 mm. We demonstrate how results from these studies can be understood by morphological characteristics of the species. We predict codend size selection based on morphological data collected from golden redfish (S. marinus) individuals. Further, consistent with previously reported morphological similarities between the three redfish species, we show the predictions for S. marinus may successfully be extrapolated to understand experimental codend size selectivity results reported for S. mentella and S. fasciatus. In addition to the comparison with previously reported data, we present new experimental results for a codend applied in Northeast Atlantic redfish trawl fishery.
{"title":"Understanding the Size Selectivity of Redfish (Sebastes spp.) in North Atlantic Trawl Codends","authors":"B. Herrmann, M. Sistiaga, K. N. Nielsen, R. Larsen","doi":"10.2960/J.V44.M680","DOIUrl":"https://doi.org/10.2960/J.V44.M680","url":null,"abstract":"The majority of trawl selectivity studies for the three redfish species of particular commercial importance in North Atlantic fisheries: Sebastes marinus, Sebastes mentella and Sebastes fasciatus, are based on data collected from diamond mesh codends with mesh sizes ranging from 88 mm to 147 mm. We demonstrate how results from these studies can be understood by morphological characteristics of the species. We predict codend size selection based on morphological data collected from golden redfish (S. marinus) individuals. Further, consistent with previously reported morphological similarities between the three redfish species, we show the predictions for S. marinus may successfully be extrapolated to understand experimental codend size selectivity results reported for S. mentella and S. fasciatus. In addition to the comparison with previously reported data, we present new experimental results for a codend applied in Northeast Atlantic redfish trawl fishery.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256890","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}
An overview of tagging studies on haddock conducted since the 1920s demonstrates an erosion of population components, partially mirrored by progressive changes in perceived commercial fishery stock structure through time. In Canadian waters our fisheries likely started with five or more discrete populations, of which only two populations remain clearly discernible. The two survivors are highly migratory populations that spend the winter offshore, only coming inshore in warmer months. It is indeterminate if any non-migratory inshore haddock populations still exist.
{"title":"Old and Older Perceptions of the Migrations and Distribution of Haddock,Melanogrammus aeglefinus, in Northwest Atlantic Waters from Tagging Conducted in the Bay of Fundy, Georges Bank, Scotian Shelf, and the Southern Gulf of St Lawrence.","authors":"G. M. Fowler","doi":"10.2960/J.V43.M676","DOIUrl":"https://doi.org/10.2960/J.V43.M676","url":null,"abstract":"An overview of tagging studies on haddock conducted since the 1920s demonstrates an erosion of population components, partially mirrored by progressive changes in perceived commercial fishery stock structure through time. In Canadian waters our fisheries likely started with five or more discrete populations, of which only two populations remain clearly discernible. The two survivors are highly migratory populations that spend the winter offshore, only coming inshore in warmer months. It is indeterminate if any non-migratory inshore haddock populations still exist.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256838","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}
{"title":"Occurrence of Grey Gurnard (Eutrigla gurnardus, Linnaeus 1758) in West Greenland Waters","authors":"T. Neudecker, M. Stein","doi":"10.2960/J.V43.M671","DOIUrl":"https://doi.org/10.2960/J.V43.M671","url":null,"abstract":"","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256785","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}
Combining information from ichthyoplankton and bottom trawl surveys conducted since the mid 2000s, we present the first report on the distribution and development of early stages of Greenland halibut in the Gulf of St. Lawrence. Forty Greenland halibut larvae were captured during the early surveys (end of April, early May), especially south and north of Anticosti Island. Only 10 larvae were captured during the June surveys, few south of Anticosti Island and most were still found near the southeast end and north of the island over the deep Anticosti Channel. In August, newly settled postlarvae were found mainly north of Anticosti Island but also at deep stations in the Laurentian Channel and westward up to the Lower St. Lawrence Estuary. From the combined distribution of larva and newly settled postlarva standard lengths over sampling dates, it was estimated that the larvae would have hatched in late March or early April. Taken together, data on the distribution of Greenland halibut larvae and postlarvae support the conclusion of late-winter spawning in the Gulf of St. Lawrence, possibly over an area located in the deep Laurentian Channel southwest of Newfoundland.
{"title":"Greenland halibut (Reinhardtius hippoglossoidesWalbaum, 1792) early stage distribution in the Gulf of St. Lawrence","authors":"P. Ouellet, A. O. Bui, B. Bernier","doi":"10.2960/J.V43.M677","DOIUrl":"https://doi.org/10.2960/J.V43.M677","url":null,"abstract":"Combining information from ichthyoplankton and bottom trawl surveys conducted since the mid 2000s, we present the first report on the distribution and development of early stages of Greenland halibut in the Gulf of St. Lawrence. Forty Greenland halibut larvae were captured during the early surveys (end of April, early May), especially south and north of Anticosti Island. Only 10 larvae were captured during the June surveys, few south of Anticosti Island and most were still found near the southeast end and north of the island over the deep Anticosti Channel. In August, newly settled postlarvae were found mainly north of Anticosti Island but also at deep stations in the Laurentian Channel and westward up to the Lower St. Lawrence Estuary. From the combined distribution of larva and newly settled postlarva standard lengths over sampling dates, it was estimated that the larvae would have hatched in late March or early April. Taken together, data on the distribution of Greenland halibut larvae and postlarvae support the conclusion of late-winter spawning in the Gulf of St. Lawrence, possibly over an area located in the deep Laurentian Channel southwest of Newfoundland.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256845","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}
An interdisciplinary review was undertaken to evaluate the stock structure and management of winter flounder (Pseudopleuronectes americanus) throughout its geographic range in the northwest Atlantic. Information on morphology, tagging studies, genetics, larval dispersal, life history traits, environmental signals and meristics was considered. In the coastal waters of the United States, winter flounder are managed as three stock units; Georges Bank, Gulf of Maine and Southern New England/Mid-Atlantic. In Canadian waters, winter flounder are managed as three stock units: western Scotian Shelf (NAFO Div. 4X), eastern Scotian Shelf (NAFO Div. 4VW), and the southern Gulf of St. Lawrence (NAFO Div. 4T). Estuarine spawning, which likely plays an important role in reproductive isolation and population structure, is non-existent on Georges Bank and Browns Bank, variable in more northern habitats and may be obligate in southern New England. Contingent groups are likely present in several regions, and merit further research. Despite evidence for local population structure, information from tagging, meristic analysis, and life history studies suggest extensive mixing within stock units, thereby supporting the current U.S. management units. Genetic analysis and parasite markers indicate that Canadian management units are distinct. However, examination of inshore and offshore winter flounder within Division 4X suggests little interchange occurs between these groups. Based on their distribution and life history traits, several flounder stocks likely exist within the Div. 4T management area. A stock composition analysis of mixed-stock fisheries would be useful to facilitate the management and assessment of winter flounder in both U.S. and Canadian waters.
{"title":"An Interdisciplinary Assessment of Winter Flounder(Pseudopleuronectes americanus) Stock Structure","authors":"G. DeCelles, S. Cadrin","doi":"10.2960/J.V43.M673","DOIUrl":"https://doi.org/10.2960/J.V43.M673","url":null,"abstract":"An interdisciplinary review was undertaken to evaluate the stock structure and management of winter flounder (Pseudopleuronectes americanus) throughout its geographic range in the northwest Atlantic. Information on morphology, tagging studies, genetics, larval dispersal, life history traits, environmental signals and meristics was considered. In the coastal waters of the United States, winter flounder are managed as three stock units; Georges Bank, Gulf of Maine and Southern New England/Mid-Atlantic. In Canadian waters, winter flounder are managed as three stock units: western Scotian Shelf (NAFO Div. 4X), eastern Scotian Shelf (NAFO Div. 4VW), and the southern Gulf of St. Lawrence (NAFO Div. 4T). Estuarine spawning, which likely plays an important role in reproductive isolation and population structure, is non-existent on Georges Bank and Browns Bank, variable in more northern habitats and may be obligate in southern New England. Contingent groups are likely present in several regions, and merit further research. Despite evidence for local population structure, information from tagging, meristic analysis, and life history studies suggest extensive mixing within stock units, thereby supporting the current U.S. management units. Genetic analysis and parasite markers indicate that Canadian management units are distinct. However, examination of inshore and offshore winter flounder within Division 4X suggests little interchange occurs between these groups. Based on their distribution and life history traits, several flounder stocks likely exist within the Div. 4T management area. A stock composition analysis of mixed-stock fisheries would be useful to facilitate the management and assessment of winter flounder in both U.S. and Canadian waters.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256805","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}
Interannual zooplankton abundance trends in the Middle Atlantic Bight region of the US Northeast continental shelf are described and related to variations in environmental variables for the years 1977 to 2009. Depth integrated plankton samples were collected on bimonthly broad-scale surveys of the region. Abundance information indicates that the region’s zooplankton population is flourishing. Total counts and biomass levels have been mostly above average in the second-half of the sampling period. Multivariate analysis of abundance data supported these findings by classifying the time series into three consecutive groups of years defined by varying abundance levels: 1) average in the late 1970s, 2) low in the 1980s, and 3) above average from 1993 to 2009. This analysis identified eleven taxa that had similar increasing interannual abundance patterns during the time series. Evidence is presented that these changes may be related to warming temperatures in the Northwest Atlantic. The increasing abundance levels of the eleven taxa was positively correlated (p<0.01) to surface temperature measurements and the recent trends of the Atlantic Multidecadal Oscillation index. A second, smaller group of six taxa had correlated abundance trends that were variable through the years, with peak production associated with low salinity in the late 1990s.
{"title":"Inter-decadal Variability of Zooplankton Abundance in the Middle Atlantic Bight","authors":"J. Kane","doi":"10.2960/J.V43.M674","DOIUrl":"https://doi.org/10.2960/J.V43.M674","url":null,"abstract":"Interannual zooplankton abundance trends in the Middle Atlantic Bight region of the US Northeast continental shelf are described and related to variations in environmental variables for the years 1977 to 2009. Depth integrated plankton samples were collected on bimonthly broad-scale surveys of the region. Abundance information indicates that the region’s zooplankton population is flourishing. Total counts and biomass levels have been mostly above average in the second-half of the sampling period. Multivariate analysis of abundance data supported these findings by classifying the time series into three consecutive groups of years defined by varying abundance levels: 1) average in the late 1970s, 2) low in the 1980s, and 3) above average from 1993 to 2009. This analysis identified eleven taxa that had similar increasing interannual abundance patterns during the time series. Evidence is presented that these changes may be related to warming temperatures in the Northwest Atlantic. The increasing abundance levels of the eleven taxa was positively correlated (p<0.01) to surface temperature measurements and the recent trends of the Atlantic Multidecadal Oscillation index. A second, smaller group of six taxa had correlated abundance trends that were variable through the years, with peak production associated with low salinity in the late 1990s.","PeriodicalId":16669,"journal":{"name":"Journal of Northwest Atlantic Fishery Science","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"69256822","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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