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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 [...]

Copyright of Atmosphere -- Ocean (Taylor & Francis Ltd) is the property of Taylor & Francis Ltd 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.)

Abstract: The recommendation of mid-ocean exchange of ballast water has resulted in significant release of aquatic invasive species in shelf areas. This paper describes a semiquantitative risk assessment model developed [...]

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]

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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.)

ABSTRACT Globally, management decisions for recently established invertebrate fisheries are based on limited information. The negative consequences are being realized as now at least one-third of invertebrate fisheries are over-exploited, collapsed or closed. Management of a fishery should be based on abundance and productivity data. This information is often unavailable but in some jurisdictions, spatial distributions are known. A methodology for designating a network of reserves for sedentary invertebrates, using sea cucumber ( Cucumaria frondosa) on the Scotian Shelf, Canada is proposed, as a case study., It is assumed that there is a positive relationship between spawner density and per capita population growth rate in sedentary broadcast spawners and that fertilization success declines rapidly at low densities. Protection of high-density habitat would safeguard critical spawner density, especially when the critical density is unknown. Using spatial distribution, a method to identify size and location of reserves designed to protect high-density habitat was developed., First, geographically distinct regional-scale clusters are identified. Within clusters, the characteristic patch scale was determined through spatial autocorrelation analysis. The size of reserves can be set as 50% of each high-density patch based on an appropriate risk-averse approach., The allocation of reserve size and location is not dependent on results of a numerical circulation model. However, the analysis was refined by using one to predict larval drift patterns, and connectivity among patches. Reserve boxes were then designated to safeguard from 30 to 65% of each high-density patch., Marine reserves do not work if inappropriately sited. In the absence of any other information, it is argued that siting reserves on high-density areas is an essential and appropriate approach to data-poor invertebrate fisheries management. A high percentage of each high-density patch could serve as risk-averse 'spatial management' reference points, and could be modified once replenishment rates are known., Copyright © Her Majesty the Queen in Right of Canada 2013 [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.)

A characteristic of biophysical models (BPM) is that they contain a number of parameters that are poorly known or only known within a range of possible values. This paper describes an efficient optimized BPM developed to simulate the Icelandic cod pelagic 0-group survey data. The method is based on presenting the results as a probability density function (PDF) that a particle released from a given spawning drifts downstream to a given grid location some time later. The model determines egg production model parameters (peak spawning time, spawning duration, number of eggs released) for each of 15 spawning grounds as the solution of a bound constrained optimization problem that minimizes model-data misfits in abundance and age distributions. The model is applied to simulating the 2002 and 2003 summer survey data. The model does a reasonable job of simulating the observed inshore / offshore abundance gradient and spatial age gradient for each year. Problem areas are explained from the point of view of model limitations. We caution that the results from an optimized model should always be assessed with the model’s limitations in mind and with respect to whatever biological data are available. [ABSTRACT FROM AUTHOR]

Brickman, D., Marteinsdottir, G., Logemann, K., and Harms, I. H. 2007. Drift probabilities for Icelandic cod larvae – ICES Journal of Marine Science, 64, 49–59. The climatological distribution of juvenile Icelandic cod is characterized by a negative spatial age gradient, with a fairly abrupt decrease in age near the northwest corner of Iceland, and a spatial abundance gradient with higher concentrations of 0-group fish inshore. Flowfields from a high-resolution circulation model developed for Icelandic waters were used to investigate larval drift from the various spawning grounds in Icelandic coastal waters to understand the distribution of 0-group fish. To present the results clearly, drift probability density functions (pdfs) are derived describing the probability of drifting from a given spawning ground to a given spatial region over a specified time interval. These pdfs are used to determine the spawning grounds most probably contributing to the observed age distribution. The observed spatial gradient in age is likely due to differences in the spawning location of larvae, with older larvae originating in spawning grounds in the southwest and younger larvae from farther north. In general, the contribution from the main spawning grounds in the southwest is predicted to decrease with clockwise distance from the source region. The pdf technique was also used to investigate drift from regions on the south coast of Iceland corresponding to known or possible subpopulation spawning grounds, to see whether these spawning areas are associated with distinct drift patterns. This technique is a useful way to present larval drift results and to facilitate comparison with real data. [ABSTRACT FROM PUBLISHER]

Lagrangian stochastic (LS) modeling is a common technique in atmospheric boundary layer modeling but is relatively new in coastal oceanography. This paper presents some fundamental aspects of LS modeling as they pertain to oceanography. The theory behind LS modeling is reviewed and an introduction to the substantial atmospheric literature on the subject is provided. One of the most important properties of an LS model is that it maintains an initially uniform distribution of particles uniform for all time—the well-mixed condition (WMC). Turbulent data for use in an oceanic LS model (LSM) are typically output at discrete positions by a general circulation model. Tests for the WMC are devised, and it is shown that for inhomogeneous turbulence the data output by an oceanic general circulation model is such that the WMC cannot be demonstrated. It is hypothesized that this is due to data resolution problems. To test this hypothesis analytical turbulence data are constructed and output at various resolutions to show that the WMC can only be demonstrated if the resolution is high enough (the required resolution depending on the inhomogeneity of the turbulence data). The output of an LSM represents one trial of possible ensemble and this paper seeks to learn the ensemble average properties of the dispersion. This relates to the number of particles or trials that are performed. Methods for determining the number of particles required to have statistical certainty in one's results are demonstrated, and two possible errors that can occur when using too few particles are shown. [ABSTRACT FROM AUTHOR]

Presents information on a study which modified the DieCAST ocean circulation model. Limiting features of the model; Discussion on the two-dimensional linear problem; Model description; Validation of the model.

Copyright of Atmosphere - Ocean (Canadian Meteorological & Oceanographic Society) is the property of Canadian Meteorological & Oceanographic Society 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.)

The article reports on the multispecies biogeographic cline associated with climatic gradient and seasonal temperature in northwest Atlantic. Topics include the macroecological phenomenon demonstrated by the genetic break among various marine species, the association between the marine population distribution and the climate forecast and habitat suitability, and the effect of cryptic diversity associated with climate variation on how the species response to climate change.