scholarly journals Probabilistic-based genetic assignment model: assignments to subcontinent of origin of the West Greenland Atlantic salmon harvest

2009 ◽  
Vol 67 (3) ◽  
pp. 537-550 ◽  
Author(s):  
Timothy F. Sheehan ◽  
Christopher M. Legault ◽  
Timothy L. King ◽  
Adrian P. Spidle
Keyword(s):  
Atlantic Salmon ◽  
North American ◽  
Dna Analysis ◽  
Biological Data ◽  
The West ◽  
Genetic Assignment ◽  
West Greenland ◽  
Assignment Model ◽  
Misclassification Rates ◽  
Mixed Stock

Abstract Sheehan, T. F., Legault, C. M., King, T. L., and Spidle, A. P. 2010. Probabilistic-based genetic assignment model: assignments to subcontinent of origin of the West Greenland Atlantic salmon harvest. – ICES Journal of Marine Science, 67: 537–550. A multistock Atlantic salmon (Salmo salar) fishery operates off the coast of West Greenland and harvests fish of North American and European origin. Annual landings peaked in 1971 at 2700 t, but declined to 22 t in 2003. Biological data are collected to characterize the catch and its stock composition. Multilocus genotypes, generated via microsatellite DNA analysis, are used to derive statistics on continent of origin and less accurate finer-scale assignments. We developed a probabilistic-based genetic assignment (PGA) model to estimate the contribution of salmon from individual North American rivers in the 2000–2003 West Greenland catch. Uncertainty associated with finer-scale assignments is addressed by incorporating estimated misclassification rates and by reporting results as distributions generated via Monte Carlo resampling. US-origin fish represented ∼1% (by number) of the salmon harvested at West Greenland during the years 2000–2003. The resulting loss of spawners to this stock complex was approximately half the estimated adult returns in 2001, but was below 4% in the other 3 years. This is the first attempt to partition the US component of the West Greenland mixed-stock fishery to its finer parts. The approach can be used to identify the effects of fishing on individual stocks within any multistock complex where genetic samples of known origin are available.

scholarly journals Genetic mixed-stock analysis disentangles spatial and temporal variation in composition of the West Greenland Atlantic Salmon fishery

2016 ◽  
Vol 73 (9) ◽  
pp. 2311-2321 ◽  
Author(s):  
Ian R. Bradbury ◽  
Lorraine C. Hamilton ◽  
Timothy F. Sheehan ◽  
Gerald Chaput ◽  
Martha J. Robertson ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
North American ◽  
Temporal Stability ◽  
Spatial And Temporal Variation ◽  
Published Data ◽  
The West ◽  
West Greenland ◽  
Archived Samples ◽  
Mixed Stock ◽  
Salmon Fishery

Abstract The West Greenland Atlantic Salmon (Salmo salar) fishery represents the largest remaining mixed-stock fishery for Atlantic Salmon in the Northwest Atlantic and targets multi-sea-winter (MSW) salmon from throughout North America and Europe. We evaluated stock composition of salmon harvested in the waters off West Greenland (n = 5684 individuals) using genetic mixture analysis and individual assignment to inform conservation of North American populations, many of which are failing to meet management targets. Regional contributions to this fishery were estimated using 2169 individuals sampled throughout the fishery between 2011 and 2014. Of these, 22% were identified as European in origin. Major North American contributions were detected from Labrador (∼20%), the Southern Gulf/Cape Breton (29%), and the Gaspe Peninsula (29%). Minor contributions (∼5%) were detected from Newfoundland, Ungava, and Quebec regions. Region-specific catches were extrapolated using estimates of composition and fishery catch logs and harvests ranged from 300 to 600 and 2000 to 3000 individuals for minor and major constituents, respectively. To evaluate the temporal stability of the observed fishery composition, we extended the temporal coverage through the inclusion of previously published data (1995–2006, n = 3095) and data from archived scales (1968–1998, n = 420). Examination of the complete time-series (47 years) suggests relative stability in stock proportions since the late 1980s. Genetic estimates of stock composition were significantly associated with model-based estimates of returning MSW salmon (individual years r = 0.69, and overall mean r = 0.96). This work demonstrates that the analysis of both contemporary and archived samples in a mixed-stock context can disentangle levels of regional exploitation and directly inform assessment and conservation of Atlantic Salmon in the West Greenland interceptory Atlantic Salmon fishery.

Discrimination between Atlantic Salmon (Salmo salar) of North American and European Origin using Restriction Analyses of Mitochondrial DNA

1991 ◽  
Vol 48 (5) ◽  
pp. 884-893 ◽  
Author(s):  
Eldredge Bermingham ◽  
Stephen H. Forbes ◽  
Kevin Friedland ◽  
Carles Pla
Keyword(s):  
Mitochondrial Dna ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
North American ◽  
Restriction Endonucleases ◽  
The West ◽  
European Origin ◽  
West Greenland ◽  
Atlantic Salmon Salmo Salar ◽  
The North

Twenty restriction endonucleases were used to study mitochondrial DNA (mtDNA) polymorphism in 11 hatchery strains of Atlantic salmon (Salmo salar) representing geographically separated populations in Europe and North America. The North American salmon mtDNAs studied were readily distinguished, by a minimum of seven restriction site differences, from fish of European origin. These results suggested that restriction analyses of mtDNA might provide a useful method for determining the proportions of European and North American Atlantic salmon caught in the West Greenland fishery. To test this proposition, we analyzed 328 salmon caught in the 1987 West Greenland fishery including 68 fish with coded wire or Carlin tags which provided the geographic source of the tagged salmon. We correctly identified the continent of origin for 67 of the 68 physically tagged salmon using two informative restriction endonucleases. This study provides a clear indication of the usefulness of mtDNA for discriminating between European and North American Atlantic salmon caught in the West Greenland fishery and for mixed-fishery analysis in general.

Instant myth: the case of the west Greenland salmon

Polar Record ◽  
1975 ◽  
Vol 17 (109) ◽  
pp. 355-358 ◽  
Author(s):  
M. J. Dunbar
Keyword(s):  
Atlantic Salmon ◽  
The West ◽  
West Greenland ◽  
The Public ◽  
Davis Strait ◽  
Pelagic Fishery

It has been said that scientific truths begin as heresies and end as myths, enjoying a period of orthodox acceptance in between. It must be rare, if this is so, for a myth to be imposed upon the public as a “truth”, to be accepted immediately as such, and then to suffer excommunication as heresy. Such a case is at hand in the matter of the sea-life area of the Atlantic Salmon in Davis Strait and of the start of a new pelagic fishery.

Effects of Oceanic Variations and the West Greenland Fishery on Age at Maturity of Icelandic West Coast Stocks of Atlantic Salmon (Salmo salar)

1989 ◽  
Vol 46 (1) ◽  
pp. 16-27 ◽  
Author(s):  
Dennis L. Scarnecchia ◽  
Árni Ísaksson ◽  
S. E. White
Keyword(s):  
Time Series ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
West Coast ◽  
Strongly Correlated ◽  
The West ◽  
West Greenland ◽  
Atlantic Salmon Salmo Salar ◽  
The Mean ◽  
Salmon Fishery

Investigations were conducted on the effects of oceanic variations (as measured by sea temperatures) and catches by the West Greenland salmon fishery on the sea age composition of Atlantic salmon (Salmo salar) stocks from 21 Icelandic west coast rivers. Annual ratios of grilse to two-sea-winter (2SW) salmon were strongly correlated among the 21 rivers. All eight rivers with time series extending back before the expansion of the West Greenland fishery showed lower ratios during the earlier period. Only 2 of the 21 rivers, however, had significantly declining ratios over their time series. In addition, for only one river was West Greenland catch significantly related to the ratios (P < 0.05), and for only one river did ratios increase when the expanded West Greenland fishery was active. Overall, the effects of the fishery on stock composition are evidently minimal. The mean April–May temperature when the smolts were to migrate out of rivers was significantly and positively related to subsequent ratios for five of the rivers, which, along with correlations among the ratios, indicated that more rapid growth of smolts in their first summer may have increased the ratios of grilse to 2SW salmon on several rivers.

scholarly journals Inferring Atlantic salmon post-smolt migration patterns using genetic assignment

2019 ◽  
Vol 6 (10) ◽  
pp. 190426 ◽  
Author(s):  
A. C. Harvey ◽  
M. Quintela ◽  
K. A. Glover ◽  
Ø. Karlsen ◽  
R. Nilsen ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Sea Lice ◽  
Fish Farms ◽  
Migration Routes ◽  
Migration Patterns ◽  
Genetic Assignment ◽  
Risk Of Mortality ◽  
Migratory Patterns ◽  
Inner Region ◽  
Mixed Stock

Understanding migratory patterns is important for predicting and mitigating unwanted consequences of environmental change or anthropogenic challenges on vulnerable species. Wild Atlantic salmon undergo challenging migrations between freshwater and marine environments, and the numbers of salmon returning to their natal rivers to reproduce have declined over several decades. Mortality from sea lice linked to fish farms within their seaward migration routes is proposed as a contributing factor to these declines. Here, we used 31 microsatellite markers to establish a genetic baseline for the main rivers in the Hardangerfjord, western Norway. Mixed stock analysis was used to assign Atlantic salmon post-smolts caught in trawls in 2013–2017 back to regional reporting units. Analyses demonstrated that individuals originating from rivers located in the inner region of the fjord arrived at the outer fjord later than individuals from middle and outer fjord rivers. Therefore, as post-smolts originating from inner rivers also have to migrate longer distances to exit the fjord, these data suggest that inner fjord populations are more likely to be at risk of mortality through aquaculture-produced sea lice, and other natural factors such as predation, than middle or outer fjord populations with earlier exit times and shorter journeys. These results will be used to calibrate models estimating mortality from sea lice on wild salmon for the regulation of the Norwegian aquaculture industry.

Parasites in Antarctic krill guts inferred from DNA sequences

2019 ◽  
Vol 31 (1) ◽  
pp. 16-22 ◽  
Author(s):  
Alison C. Cleary ◽  
Maria C. Casas ◽  
Edward G. Durbin ◽  
Jaime Gómez-Gutiérrez
Keyword(s):  
Dna Sequences ◽  
High Frequency ◽  
Dna Analysis ◽  
Antarctic Krill ◽  
Euphausia Superba ◽  
Gut Contents ◽  
The West ◽  
West Antarctic ◽  
Wide Range

AbstractThe keystone role of Antarctic krill,Euphausia superbaDana, in Southern Ocean ecosystems, means it is essential to understand the factors controlling their abundance and secondary production. One such factor that remains poorly known is the role of parasites. A recent study of krill diet using DNA analysis of gut contents provided a snapshot of the parasites present within 170E. superbaguts in a small area along the West Antarctic Peninsula. These parasites includedMetschnikowiaspp. fungi,Haptoglossasp. peronosporomycetes,LankesteriaandParalecudinaspp. apicomplexa,Stegophorussp. nematodes, andPseudocolliniaspp. ciliates. Of these parasites,Metschnikowiaspp. fungi andPseudocolliniaspp. ciliates had previously been observed inE. superba, as had other genera of apicomplexans, though notLankesteriaandParalecudina.In contrast, nematodes had previously only been observed in eggs ofE. superba, and there are no literature reports of peronosporomycetes in euphausiids.Pseudocolliniaspp., parasitoids which obligately kill their host, were the most frequently observed infection, with a prevalence of 12%. The wide range of observed parasites and the relatively high frequency of infections suggest parasites may play a more important role than previously acknowledged inE. superbaecology and population dynamics.

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