Open data that can be easily incorporated into analyses are essential for developing ecosystem approaches to marine ecological management: a common goal in fisheries policy in many countries. Although it is not always clear what constitutes an ecosystem approach, it always involves scientists working with a large variety of data and information, including data from physical and oceanographic sampling, multispecies surveys, and other sources describing human pressures. This can be problematic for analysts because these data, even when available, are often held in disparate datasets that do not necessarily correspond at appropriate temporal and spatial scales. Data can often only be obtained by specific requests to individuals in governmental agencies who are delivering on an increasing number of data requests as interest grows in practical ecosystem approach implementation. This data access model is not sustainable and hinders the momentum for ecosystem approach development. We describe a data bundling R package that makes data and climate projections available at appropriate scales to facilitate development of an ecosystem approach for the Gulf of St. Lawrence, Canada. This approach integrates closely with the present workflow of most government analysts, academics in fisheries, and scientists in private industry. The approach conforms with open data initiatives and makes data easily available globally while relieving some of the burden of data provision that can fall to some individuals in government laboratories. The structure and approach are generic, adaptable, and transferable to other regions and jurisdictions.

Species with widespread distributions play a crucial role in our understanding of climate change impacts on population structure. In marine species, population structure is often governed by both high connectivity potential and selection across strong environmental gradients. Despite the complexity of factors influencing marine populations, studying species with broad distribution can provide valuable insights into the relative importance of these factors and the consequences of climate-induced alterations across environmental gradients. We used the northern shrimp Pandalus borealis and its wide latitudinal distribution to identify current drivers of population structure and predict the species' vulnerability to climate change. A total of 1514 individuals sampled across 24° latitude were genotyped at high geographic (54 stations) and genetic (14,331 SNPs) resolutions to assess genetic variation and environmental correlations. Four populations were identified in addition to finer substructure associated with local adaptation. Geographic patterns of neutral population structure reflected predominant oceanographic currents, while a significant proportion of the genetic variation was associated with gradients in salinity and temperature. Adaptive landscapes generated using climate projections suggest a larger genomic offset in the southern extent of the P. borealis range, where shrimp had the largest adaptive standing genetic variation. Our genomic results combined with recent observations point to further deterioration in southern regions and an impending vulnerable status in the regions at higher latitudes for P. borealis. They also provide rare insights into the drivers of population structure and climatic vulnerability of a widespread meroplanktonic species, which is crucial to understanding future challenges associated with invertebrates essential to ecosystem functioning.

AbstractBiodiversity assessment is an important part of conservation management that ideally can be accomplished with noninvasive methods without influencing the structure and functioning of ecosystems. Environmental DNA (eDNA) metabarcoding has provided a promising tool to enable fast and comprehensive monitoring of entire ecosystems, but widespread adoption of this technique requires performance evaluations that compare it with conventional surveys. We compared eDNA metabarcoding and trawling data to evaluate their efficiency to characterize demersal fish communities in the Estuary and Gulf of Saint‐Lawrence, Canada. Seawater and bottom trawling samples were collected in parallel at 84 stations. For a subset of 30 of these stations, water was also collected at three different depths (15, 50, and 250 m) across the water column. An eDNA metabarcoding assay based on the 12S mitochondrial gene using the MiFish‐U primers was applied to detect fish eDNA. We detected a total of 88 fish species with both methods combined, with 72 species being detected by eDNA, 64 species detected by trawl, and 47 species (53%) overlapped between both methods. eDNA was more efficient for quantifying species richness, mainly because it detected species known to be less vulnerable to trawling gear. Our results indicated that the relative abundance estimated by eDNA and trawl is significantly correlated for species detected by both methods, while the relationship was also influenced by environmental variables (temperature, depth, salinity, and oxygen). Integrating eDNA metabarcoding to bottom trawling surveys could provide additional information on vertical fish distribution in the water column. Environmental DNA metabarcoding thus appears to be a reliable and complementary approach to trawling surveys for documenting fish biodiversity, including for obtaining relative quantitative estimates in the marine environment.

The St. Lawrence is a vast and complex socio-ecological system providing a wealth of services that sustain numerous economic sectors. This ecosystem is subject to significant human pressures that overlap and potentially interact with climate-driven environmental changes. Our objective in this paper was to systematically characterize the distribution and intensity of drivers of environmental change (hereafter, drivers) in the St. Lawrence System. We gathered data-based indicators for 22 coastal, climate, fisheries, and marine traffic drivers through collaborations, existing environmental initiatives and open data portals. We show that few areas of the St. Lawrence are free of cumulative exposure. The Estuary, Anticosti Gyre, and coastal areas are particularly exposed, especially in the vicinity of urban centers. We identified six distinct clusters with similar suites of co-occurring drivers and show that certain driver combinations are inherent to different regions of the St. Lawrence and that coastal areas are exposed to all driver types. Of particular concern are two clusters capturing most exposure hotspots and that show the convergence of contrasting cumulative exposure profiles at the head of the Laurentian Channel. Sharing knowledge of drivers emerged as a priority to facilitate future environmental assessment efforts. We thus launch eDrivers, an open knowledge platform gathering experts committed to structuring, standardizing and sharing knowledge on drivers of environmental change in support of holistic science and management. eDrivers was built on a series of guiding principles upholding existing data management and open science standards. We therefore expect it to evolve through time to address knowledge gaps and refine current driver layers. Ultimately, we believe that eDrivers represents a much needed solution that could radically influence broad scale research and management practices by increasing knowledge accessibility and interoperability.

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Climate and density-dependent effects are important drivers of recruitment (R). In the Gulf of St. Lawrence (GSL), recent years indicated an exceptional warming of water associated with variations in plankton phenology and fish abundance. At the same time, northern shrimp (Pandalus borealis) recruitment and stock dynamics fluctuated greatly, but the underlying mechanisms remain poorly understood. We estimated recruitment from yearly fisheries independent abundance estimates for three different northern shrimp stocks in the GSL (Sept-Iles, Anticosti, and Esquiman). For 2001-2016, we quantified how northern shrimp R changed in relation to physical variables, phytoplankton bloom characteristics, zooplankton abundance and phenology, and predator biomass. Results indicated that northern shrimp R seemed related to phytoplankton bloom characteristics and resulting zooplankton phenology in addition to northern shrimp adult abundance, rather than to fish predator biomass. Importantly, the significant variables explaining the R were stock specific, implying that environmental variability and stock abundance effects depend on the area considered. In future, Esquiman area might show increasing northern shrimp R under moderate warming but northern shrimp Sept-Iles R might be impaired. These results improve our understanding of stock-specific northern shrimp recruitment dynamics in a changing environment and can ultimately improve its management in the GSL.

Decapod shrimps typically occupy lower trophic levels, often as omnivores, and many have high population turnover rates, which makes shrimp populations susceptible to changes in predator abundance and environmental change. The increased biomass of northern shrimp Pandalus boreahs in many parts of the NW Atlantic has been associated with the collapse of predatory fish populations and changes in water temperature. In this study, we show that biomass of many shrimp species in the Gulf of St. Lawrence (Canada) increased between 4- and 100-fold between the late 1980s and mid-2000s. Multivariate analyses based on trawl survey data during a period of relative stability (2004-2015) that followed the increase revealed species assemblages that were strongly spatially structured and which were associated with depth and bottom water temperatures. Univariate analyses of the associations between individual species' densities and depth and temperature revealed that approximately half of the species had narrow temperature associations, suggesting that these species may be susceptible to projected warming of the ecosystem. Furthermore, all species in the northern Gulf of St. Lawrence will be affected by recent and ongoing increases in predator biomass. In contrast, predator biomasses continue to decrease in the southern Gulf of St. Lawrence.

IV RESUME V INTRODUCTION 1 METHODS 1 DATA SOURCES 1 Environmental indices 2 Potential fish prey indices 2 Beluga whale population and individual indices 3 DATA ANALYSES 4 Data standardization 4 Principal Component Analyses (PCA) 4 Serial t-test Analysis for Regime Shift identification (STARS) 4 RESULTS 5 GENERAL ECOSYSTEM CHANGES: 1990-2012 5 POTENTIAL CHANGES IN BELUGA HABITAT 6 DISCUSSION 7 SUMMARY 11 ACKNOWLEDGEMENTS 12 LITERATURE CITED 12 TABLES 16 FIGURES 19 APPENDIX 28

In male mice, deficiency of hormone sensitive lipase (HSL, Lipe gene, E.C.3.1.1.3) causes deficient spermatogenesis, azoospermia, and infertility. Postmeiotic germ cells express a specific HSL isoform that includes a 313 amino acid N-terminus encoded by a testis-specific exon (exon T1). The remainder of testicular HSL is identical to adipocyte HSL. The amino acid sequence of the testis-specific exon is poorly conserved, showing only a 46% amino acid identity with orthologous human and rat sequences, compared with 87% over the remainder of the HSL coding sequence, providing no evidence in favor of a vital functional role for the testis-specific N-terminus of HSL. However, exon T1 is important for Lipe transcription; in mouse testicular mRNA, we identified 3 major Lipe transcription start sites, finding numerous testicular transcription factor binding motifs upstream of the transcription start site. We directly explored two possible mechanisms for the infertility of HSL-deficient mice, using mice that expressed mutant HSL transgenes only in postmeiotic germ cells on a HSL-deficient background. One transgene expressed human HSL lacking enzyme activity but containing the testis-specific N-terminus (HSL-/-muttg mice). The other transgene expressed catalytically inactive HSL with the testis-specific N-terminal peptide (HSL-/-atg mice). HSL-/-muttg mice were infertile, with abnormal histology of the seminiferous epithelium and absence of spermatozoa in the epididymal lumen. In contrast, HSL-/-atg mice had normal fertility and normal testicular morphology. In conclusion, whereas the catalytic function of HSL is necessary for spermatogenesis in mice, the presence of the N-terminal testis-specific fragment is not essential.

In order to have a global view of ecosystem changes associated with the collapse of groundfish species in the Gulf of St. Lawrence during the early 1990s, Ecopath mass-balance models were constructed incorporating uncertainty in the input data. These models covered two ecosystems (northern and southern Gulf of St. Lawrence; NAFO divisions 4RS and 4T), and two time periods (before the collapse, in the mid-1980s, and after it, in the mid-1990s). Our analyses revealed that the ecosystem structure shifted dramatically from one previously dominated by piscivorous groundfish and small-bodied forage species during the mid-1980s to one now dominated only by small-bodied pelagic species during the mid-1990s in both southern and northern Gulf. The species structure in the northern Gulf versus southern Gulf was different, which may explain why these two ecosystems did not recover the same way from the collapse in the early 1990s. Productivity declined in the northern Gulf after the collapse but increased in the southern Gulf. The collapse of groundfish stocks resulted in declines in the mean trophic level of the landings in both the northern and the southern Gulf. Even though fishing mortality was then intentionally reduced, this part of the total mortality was taken up by predation. The temporal changes in the internal structure of both ecosystems are reflected in their overall emergent properties.

Mass-balance models have been constructed using inverse methodology for the northern Gulf of St. Lawrence for the mid-1980s, the mid-1990s, and the early 2000s to describe ecosystem structure, trophic group interactions, and the effects of fishing and predation on the ecosystem for each time period. Our analyses indicate that the ecosystem structure shifted dramatically from one previously dominated by demersal (cod, redfish) and small-bodied forage (e.g., capelin, mackerel, herring, shrimp) species to one now dominated by small-bodied forage species. Overfishing removed a functional group in the late 1980s, large piscivorous fish (primarily cod and redfish), which has not recovered 14 years after the cessation of heavy fishing. This has left only marine mammals as top predators during the mid-1990s, and marine mammals and small Greenland halibut during the early 2000s. Predation by marine mammals on fish increased from the mid-1980s to the early 2000s while predation by large fish on fish decreased. Capelin and shrimp, the main prey in each period, showed an increase in biomass over the three periods. A switch in the main predators of capelin from cod to marine mammals occurred, while Greenland halibut progressively replaced cod as shrimp predators. Overfishing influenced community structure directly through preferential removal of larger-bodied fishes and indirectly through predation release because larger-bodied fishes exerted top-down control upon other community species or competed with other species for the same prey. Our modelling estimates showed that a change in predation structure or flows at the top of the trophic system led to changes in predation at all lower trophic levels in the northern Gulf of St. Lawrence. These changes represent a case of fishery-induced regime shift.

Mass-balance models, using inverse methodology, were applied to the southern Gulf of St. Lawrence for the mid-1980s and the mid-1990s to describe ecosystem structure, trophic group interactions, and the effects of fishing and predation on the ecosystem for periods preceding and following the collapse of groundfish stocks in this area. These models were used to determine how the ecosystem changed, and whether its structure and functioning were affected by the observed changes in key species between the two time periods. Our analyses indicate that the ecosystem structure shifted dramatically from one previously dominated by piscivorous groundfish and small-bodied forage species (e.g., capelin, herring, and shrimp) in similar proportions to one now dominated by small-bodied forage species. Overfishing removed a functional group, large-bodied demersal predators that has not been replaced 12 years after the cessation of heavy fishing, and left marine mammals such as seals and cetacea as top predators of many species (especially fishes) during the mid-1990s. Predation by marine mammals on fish increased from the mid-1980s to the mid-1990s while predation by large fish on fish decreased. A change in the prey of seals from juvenile cod to capelin occurred between the models for the mid-1980s and the mid-1990s consistent with observed shifts in the abundance of the two prey species between the two time periods. These major changes were accompanied by a decrease in total catches and a transition in landings from long-lived and piscivorous groundfish toward planktivorous pelagic fish and invertebrates.

Savenkoff, C., H. Bourdages, D.P. Swain, S.-P. Despatie, J.M. Hanson, R. Methot, L. Morissette, and M.O. Hammill. 2004. Input data and parameter estimates for ecosystem models of the southern Gulf of St. Lawrence (mid-1980s and mid-1990s). Can. Tech. Rep. Fish. Aquat. Sci. 2529: vi+105 pp. Several groundfish stocks have collapsed in many areas of the northwest Atlantic over the last ten years. Mass-balance models are being used to reconstruct trophic flows through one of the areas, the southern Gulf of St. Lawrence ecosystem (NAFO division 4T) before (mid-1980s) and after (mid-1990s) the collapse of cod stock. The whole-system model of the southern Gulf of St. Lawrence is divided into 30 functional groups or compartments from phytoplankton and detritus to marine mammals and seabirds, including harvested species of pelagic, demersal, and benthic domains. We present here details of the input data (biomass, production, consumption, export, and diet composition) for each compartment used in the modelling. The successful development of ecosystem models proposed by the Comparative Dynamics of Exploited Ecosystems in the Northwest Atlantic (CDEENA) program will provide powerful new tools to evaluate the impact of human and environmental factors on a variety of Atlantic shelf ecosystems.

Hormone-sensitive lipase (HSL, Lipe, E.C.3.1.1.3) is a multifunctional fatty acyl esterase that is essential for male fertility and spermatogenesis and that also plays important roles in the function of adipocytes, pancreatic beta-cells, and adrenal cortical cells. Gene-targeted HSL-deficient (HSL-/-) male mice are infertile, have a 2-fold reduction in testicular mass, a 2-fold elevation of the ratio of esterified to free cholesterol in testis, and unique morphological abnormalities in round and elongating spermatids. Postmeiotic germ cells in the testis express a specific HSL isoform. We created transgenic mice expressing a normal human testicular HSL cDNA from the mouse protamine-1 promoter, which mediates expression specifically in postmeiotic germ cells. Testicular cholesteryl esterase activity was undetectable in HSL-/- mice, but in HSL-/- males expressing the testicular transgene, activity was 2-fold greater than normal. HSL transgene mRNA became detectable in testes between 19 and 25 days of age, coinciding with the first wave of postmeiotic transcription in round spermatids. In contrast to nontransgenic HSL-/- mice, HSL-/- males expressing the testicular transgene were normal with respect to fertility, testicular mass, testicular esterified/free cholesterol ratio, and testicular histology. Their cauda epididymides contained abundant, normal-appearing spermatozoa. We conclude that human testicular HSL is functional in mouse testis and that the mechanism of infertility in HSL-deficient males is cell autonomous and resides in postmeiotic germ cells, because HSL expression in these cells is in itself sufficient to restore normal fertility.

Systematic aerial line-transect surveys of beluga whales, Delphinapterus leucas , were conducted in James Bay, eastern Hudson Bay, and Ungava Bay from 14 August to 3 September 2001. An estimated 7901 (SE= 1744) and 1155 (SE = 507) belugas were present at the surface in the offshore areas of James Bay and Hudson Bay, respectively. An additional 39 animals were observed in estuaries during the coastal survey, resulting in an index estimate of 1194 (SE = 507) in eastern Hudson Bay. No belugas were observed in Ungava Bay. Observations from systematic surveys conducted in 1993 and 2001 were analyzed using both line-transect and strip-transect methods to allow comparisons with the strip-transect survey conducted in 1985. A population model incorporating harvest information and fitted to aerial survey data indicates that the number of belugas in eastern Hudson Bay has declined by almost half because of high harvest levels. Subsistence harvest levels must be reduced significantly if this population is to recover.

RÉSUMÉ Morissette, L., S.-P. Despatie, C. Savenkoff, M. O. Hammill, H. Bourdages, and D. Chabot. 2003. Data gathering and input parameters to construct ecosystem models for the northern Gulf of St. Lawrence (mid-1980s). Can. Tech. Rep. Fish. Aquat. Sci. 2497: vi+94 p. In the present study, we use Ecopath and inverse methods to reconstruct trophic flows through the whole northern Gulf of St. Lawrence ecosystem (NAFO zones 4RS) for the mid1980s period, prior to the groundfish stock collapses. This was a period of relatively constant biomass for the major species. The whole-system model of the northern Gulf of St. Lawrence is divided into 32 functional groups or compartments from phytoplankton and detritus to marine mammals and seabirds, including harvested species of pelagic, demersal, and benthic domains. We present here details of the input data (biomass, production, consumption, export, and diet composition) for each compartment used for modelling. The successful development of ecosystem models proposed by the Comparative Dynamics of Exploited Ecosystems in the Northwest Atlantic (CDEENA) program will provide powerful new tools to evaluate the impact of human and environmental factors on a variety of Atlantic shelf ecosystems.