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As climate change transforms marine environments globally, species distributions correspondingly shift to locations where conditions have become or remain favourable. The ability to model these distributional shifts has been facilitated by species distribution models (SDMs). However, current SDM approaches have largely ignored climate‐driven changes in species interactions, which ultimately can have an important influence on species distributions. In this study, we utilize a long‐term, large‐scale dataset spanning 48 years and approximately 30 degrees latitude across the Canadian Atlantic shelf. We examine how climate influences the distribution and predation patterns of two invertebrates, northern shrimp Pandalus borealis and snow crab Chionoecetes opilio, aiming to evaluate the impacts of climate change on prey distributions. We found that both invertebrate species have a pronounced predicted response to climate change, with a northern shift in the distribution of northern shrimp and an overall reduction in abundance of both snow crab and shrimp associated with warming temperatures. Including predatory interactions as predictors in the SDMs (either directly via predator densities or via estimated predation rates) improved prediction accuracy for northern shrimp but not for snow crab. This is consistent with the ecology of these two species, as northern shrimp is more vulnerable to predation than snow crab. We found that the projections of future northern shrimp distributions are sensitive to the predicted spatial distribution and abundance of predators, highlighting the inherent complexity of predicting species response to climate change. Collectively, these results contribute to a broader literature that seeks to improve the capabilities of models to predict the effects of species interactions on species distributions under changing ecological conditions. [ABSTRACT FROM AUTHOR]

Northern shrimp (Pandalus borealis) represents one of the most important fisheries in the Northwest Atlantic Ocean, but few studies have considered connectivity among different management units (i.e., stocks). Using a biophysical model, we investigated potential larval dispersal among North Atlantic Fisheries Organization (NAFO) divisions and its interannual variability during the long pelagic larval phase of P. borealis (~3 months). Overall, we found a largely stable, stream-like larval connectivity system driven by the main currents that flow over both the Greenland and Canadian continental shelves, with a relatively low but consistent exchange of larvae between Greenland and Canada across the Baffin Island continental shelf. We observed highest potential settlement densities on the northwestern Greenland and Newfoundland shelves, representing retention areas that correspond to highest abundances of adult shrimp. Intermittent and variable larval exchanges of lower magnitude also occurred between populations less obviously associated with the major circulation features. Our study improves understanding of northern shrimp stock-recruitment relationships at the metapopulation level, which could help determine the appropriate spatial scale to improve management strategies. Si la peche a la crevette nordique (Pandalus borealis) est une des peches les plus importantes dans le nord-ouest de l'ocean Atlantique, peu d'etudes ont examine la connectivity entre differentes unites de gestion (c.-a-d. stocks). A l'aide d'un modele biophysique, nous avons examine la dispersion potentielle de larves entre les divisions de l'Organisation des peches de l'Atlantique Nord-Ouest (OPANO) et sa variability interannuelle durant la longue etape de larve pelagique de P. borealis (~3 mois). De faqon generale, nous avons releve un systeme stable de connectivite des larves s'apparentant a des flux oceaniques modules par les principaux courants qui parcourent les plateaux continentaux groenlandais et canadiens, et des echanges de larves assez faibles, bien que stables, entre le Groenland et le Canada a travers le plateau continental, de la terre de Baffin. Nous avons observe les plus grandes densites d'etablissement potentielles sur les plateaux du nord-ouest du Groenland et de Terre-Neuve, representant des zones de retention qui correspondent aux plus fortes abondances de crevettes adultes. Des echanges de larves intermittents et variables de moins grande ampleur ont aussi ete observes entre des populations dont l'association aux courants marins majeurs est moins evidente. L'etude ameliore la comprehension des relations entre le recrutement et les stocks de crevette nordique a l'echelle de la metapopulation, ce qui pourrait aider a etablir la bonne echelle spatiale pour ameliorer les strategies de gestion. [Traduit par la Redaction], Introduction Northern shrimp (Pandalus borealis) represents one of the most important fisheries in the Northwest Atlantic Ocean (third highest value in Canada in 2018; DFO 2019a) and the most important [...]

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We investigated the effect of environmental conditions on Atlantic mackerel spawning habitat in the southern Gulf of St. Lawrence (sGSL). Based on generalized additive models, we (i) modelled the optimal spawning habitat of mackerel in the sGSL using daily egg production (DEP) in June, (ii) predicted known and new potential present spawning habitats in the GSL and the north‐west Atlantic, and (iii) assessed how they respond to future climate change. Our findings showed that both mackerel presence–absence and given‐presence DEP were associated with sea surface temperature (10–16.5°C), salinity above 31 and depth < 120 m. Adding zooplankton showed a marked effect on the DEP given‐presence compared to the presence–absence. Predictions of spawning habitats under present (1999–2012) and future scenario (2066–2085) conditions were estimated from the presence–absence model without zooplankton, using physical conditions of the BNAM. Under present conditions, our model predicted well the main spawning habitat in the sGSL and other known secondary spawning habitats in the northern GSL (nGSL), the western and southern Newfoundland, and the north‐west Atlantic coast. Under future conditions, our study suggests that spawning habitats in the sGSL and the nGSL would expand. Our results, therefore, suggest that mackerel could benefit from a warmer GSL, minimizing the potential for a northward migration of the stock due to decreasing suitability of the sGSL as its main spawning ground, and a new but spatially limited potential habitat in Newfoundland coasts. These results can be used to inform stock management and develop adaptive management plans in the context of climate change. [ABSTRACT FROM AUTHOR]

The NAFO divisions 3NOPs4VWX5Zc Atlantic halibut (Hippoglossus hippoglussus L.) stock is managed over a large spatial scale, spanning over 20° of longitude and 6° of latitude. Previous studies have shown that female halibut in the warmer southern area mature at sizes 10-20 cm smaller than female halibut in the colder north. Our goal was to examine the role of growing degree-day (GDD, the number of days X temperature °C above a minimum threshold) on growth rate and length at maturity (LM50%). Two separate datasets, associated with the stock-wide DFO-Industry Halibut Longline Survey, were used to estimate these life history traits. GDD had a significant effect on both growth rates and probability of maturity. Females grew faster and matured at a larger size than males. Female growth rate at a reference length of 90 cm corresponding to the southerly NAFO 4X was ~11.5 cm/year, significantly faster than in the northerly NAFO division 3N (8 cm/year). Male growth rate at 90 cm corresponding to NAFO divisions 4X and 4W were 7.2 and 7.5 cm/year, significantly faster than in NAFO divisions 3N and 3Ps (5.6 and 5.8 cm/year). Both sexes matured at smaller sizes in the southern areas with higher GDD. Females in the warmer southern divisions were more likely to mature ~10-28cm less than the more northerly divisions. However, the corresponding prediction intervals for NAFO divisions were very wide. On average, fish mature at a smaller size in 4WX, but we cannot predict length at maturity for any new observations in any division. We have identified large variation in life history traits across the stock domain associated with the thermal regime. Such variation in life history traits could be used to improve the assessment models and may also be indicative of stock structure that could be eroded if not addressed in the management of the fishery. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)