Mixed-Stock Analysis of Atlantic Cod near the Gulf of St. Lawrence Based on Microsatellite DNA

Ruzzante, Daniel E.; Taggart, Christopher T.; Lang, Shelley L. C.; Cook, Doug

doi:10.2307/2641019

Cited by 33 publications

(45 citation statements)

References 67 publications

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“…Population structure was estimated with F ST (Wright, 1951) and R ST (Slatkin, 1995). Further details on procedures for obtaining these estimates are in Ruzzante et al (1998Ruzzante et al ( , 2000. Pairwise genetic distances among populations based on the Stepwise Mutational Model (SMM) were estimated using D SW (Shriver et al, 1995).…”

Section: Geneticsmentioning

confidence: 99%

“…Concerns about the potential losses of genetic diversity within the northern cod Gadus morhua L., and other cod stocks in the North West Atlantic raised by the recent collapse of these fisheries, have prompted a more accurate quantification of the relationships and mixing patterns among stock components. Such an initiative was taken recently using a mixed stock analysis approach with cod from the Gulf of St Lawrence and vicinity (Ruzzante et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Bay‐scale population structure in coastal Atlantic cod in Labrador and Newfoundland, Canada

Ruzzante

Wroblewski

Taggart

et al. 2000

Journal of Fish Biology

109

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Polymorphisms at five microsatellite DNA loci provide evidence that Atlantic cod Gadus morhua inhabiting Gilbert Bay, Labrador are genetically distinguishable from offshore cod on the north-east Newfoundland shelf and from inshore cod in Trinity Bay, Newfoundland. Antifreeze activity in the blood suggests that Gilbert Bay cod overwinter within the Bay. Gilbert Bay cod are also smaller (weight and length) for their age and consequently less fecund for their age, than cod elsewhere within the northern cod complex. The productivity and recruitment potential of coastal cod off Labrador may thus be much lower than that of offshore northern cod or of inshore cod farther south, implying that a more conservative management strategy may be required for cod from coastal Labrador than traditionally practised for northern cod inhabiting less harsh environments. Relatively high F ST and R ST measures of population structure suggest that important barriers to gene flow exist among five components that include two inshore (Gilbert and Trinity Bay) and three offshore cod aggregations on the north-east Newfoundland Shelf and the Grand Bank. D A and D SW estimates of genetic distance that involve Gilbert Bay cod are approximately three-and 10-fold larger, respectively, than estimates not involving Gilbert Bay cod. The differences between inshore cod from Gilbert Bay and Trinity Bay raise the possibility that other genetically distinguishable coastal populations may exist, or may have existed prior to the northern cod fishery collapse.Harvesting strategies for northern cod should recognize the existence of genetic diversity between inshore and offshore components as well as among coastal components. 2000 The Fisheries Society of the British Isles

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Section: Geneticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bay‐scale population structure in coastal Atlantic cod in Labrador and Newfoundland, Canada

Ruzzante

Wroblewski

Taggart

et al. 2000

Journal of Fish Biology

109

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“…A failure to recognize this unobserved diversity can lead to overestimated maximum sustainable yields, and therefore to overharvest of the more vulnerable stock components (Hutchinson, ; Sterner, ). Examples of mixed‐stock fisheries include the cod fisheries in the Gulf of St. Lawrence (Ruzzante, Taggart, Lang, & Cook, ) and the Kattegat (Lindegren et al, ), which were traditionally considered as single‐stock fisheries but turned out to be mixtures of stocks that aggregate during feeding but segregate during spawning.…”

Section: Introductionmentioning

confidence: 99%

Cryptic temporal changes in stock composition explain the decline of a flounder (Platichthys spp.) assemblage

Momigliano

Jokinen

Calboli

et al. 2019

Evolutionary Applications

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Unobserved diversity, such as undetected genetic structure or the presence of cryptic species, is of concern for the conservation and management of global biodiversity in the face of threatening anthropogenic processes. For instance, unobserved diversity can lead to overestimation of maximum sustainable yields and therefore to overharvesting of the more vulnerable stock components within unrecognized mixed‐stock fisheries. We used DNA from archival (otolith) samples to reconstruct the temporal (1976–2011) genetic makeup of two mixed‐stock flounder fisheries in the Åland Sea (AS) and the Gulf of Finland (GoF). Both fisheries have hitherto been managed as a single stock of European flounders ( Platichthys flesus ), but were recently revealed to target two closely related species: the pelagic‐spawning P. flesus and the newly described, demersal‐spawning P. solemdali . While the AS and GoF fisheries were assumed to consist exclusively of P. solemdali , P. flesus dominated the GoF flounder assemblage (87% of total) in 1983, had disappeared (0%) by 1993, and remained in low proportions (10%–11%) thereafter. In the AS, P. solemdali dominated throughout the sampling period (>70%), and P. flesus remained in very low proportions after 1983. The disappearance of P. flesus from the GoF coincides in time with a dramatic (~60%) decline in commercial landings and worsening environmental conditions in P. flesus’ northernmost spawning ground, the Eastern Gotland Basin, in the preceding 4–6 years. These results are compatible with the hypothesis that P. flesus in the GoF is a sink population relying on larval subsidies from southern spawning grounds and the cause of their disappearance is a cessation of larval supply. Our results highlight the importance of uncovering unobserved genetic diversity and studying spatiotemporal changes in the relative contribution of different stock components, as well as the underlying environmental causes, to manage marine resources in the age of rapid anthropogenic change.

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“…In the latter case, bias increases with unevenness with contributions from abundant stocks being underestimated and those from less common stocks being overestimated (see e.g. Utter & Ryman 1993; Ruzzante et al . 2000).…”

Section: Introductionmentioning

confidence: 99%

Stocking impact and migration pattern in an anadromous brown trout (Salmo trutta) complex: where have all the stocked spawning sea trout gone?

Ruzzante¹,

Hansen²,

Meldrup³

et al. 2004

Molecular Ecology

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We examined polymorphism at seven microsatellite loci among sea trout (Salmo trutta) (n = 846) collected from three areas in the Limfjord (Denmark). We then assessed their potential population source by comparing, using a mixed stock analysis (MSA) Bayesian framework, their genetic composition to that of brown trout collected from 32 tributaries pooled into nine geographical regions (n = 3801) and two hatcheries (n = 222) used for stocking. For each of the three regional sea trout groups (western, central and eastern Limfjord, n = 91, n = 426, n = 329, respectively), MSA was conducted with (i) all individuals in the group, (ii) with the subset of spawning sea trout only and (iii) with the subset of foraging, nonspawning individuals only, a subset that consisted primarily of sea trout caught during their first year at sea. For all three regional sea trout groups, a higher proportion of individuals (regardless of whether they were foraging or spawning) appear to have originated from the rivers that drain locally, than from the rivers that drain in other parts of the Limfjord. This suggests (1) that sea trout, at least during their first year at sea, undertake limited migrations within the Limfjord system and (2) that sea trout on their spawning run were caught close to their natal rivers. The proportion of sea trout of hatchery origin varied widely among all three Limfjord areas and broadly reflected regional stocking histories, with high proportions of sea trout of domestic origin in the east (39.3%), where stocking with domestic trout was practised intensely at the time of sampling, and in the west (57.2%), where a programme of coastal stocking of post smolts took place over several years in the early 1990s. In contrast, in the central Limfjord, where stocking with domestic trout was largely abandoned in the early 1990s, the proportion of sea trout of domestic origin was only 8.5%. Interestingly, for all three regional sea trout groups, virtually no sea trout of hatchery origin were found among the spawning individuals, which were on average larger than the nonspawning sea trout. These results suggest that stocked domestic brown trout that become anadromous experience high mortality at sea and are therefore largely absent among the larger, spawning individuals. We conclude that sea trout of domestic origin exhibit much reduced ability to reproduce and are unlikely to contribute significantly to the local gene pool largely because of a relatively high mortality at sea before the onset of maturity.

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Mixed-Stock Analysis of Atlantic Cod near the Gulf of St. Lawrence Based on Microsatellite DNA

Cited by 33 publications

References 67 publications

Bay‐scale population structure in coastal Atlantic cod in Labrador and Newfoundland, Canada

Bay‐scale population structure in coastal Atlantic cod in Labrador and Newfoundland, Canada

Cryptic temporal changes in stock composition explain the decline of a flounder (Platichthys spp.) assemblage

Stocking impact and migration pattern in an anadromous brown trout (Salmo trutta) complex: where have all the stocked spawning sea trout gone?

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