Régime alimentaire du béluga, Delphinapterus leucas, de l'estuaire du Saint-Laurent, Canada, tel que révélé par l'analyse des acides gras du lard

Une connaissance du régime alimentaire des espèces constitue un élément clé pour la compréhension de l’écologie des espèces. Or, peu de techniques existent afin d’examiner le régime alimentaire contemporain du béluga du Saint-Laurent étant donné le statut précaire de cette population et la rareté de contenus stomacaux chez les individus retrouvés morts. L’analyse des profils d’acides gras dans le lard et dans leurs proies potentielles constitue un outil susceptible de fournir certains indices concernant leur régime alimentaire. C’est donc dans ce but qu’une étude comparative des profils d’acides gras a été menée. Dans une première étape, le profil d’acides gras a été examiné chez environ 60 espèces de proies potentielles du béluga provenant de l’estuaire et du golfe du Saint-Laurent. Cette analyse a révélé la nécessité de considérer les effets des lipides totaux, de la taille, des saisons et des lieux d’échantillonnage lors de l’examen des profils d’acides gras des espèces afin d’améliorer le couplage des profils des proies potentielles avec ceux d’un prédateur tel que le béluga. Les profils d’acides gras du lard ont ensuite été comparés entre les bélugas et quatre espèces de pinnipèdes qui se trouvent dans l’estuaire et le golfe du Saint-Laurent. Les espèces de même que les sexes et classes d’âge ont généralement pu être distingués sur la base des profils d’acides gras. Une gamme d’analyses multivariées ont révélé des différences qui semblaient liées à des acides gras d’origine alimentaire, confirmant ainsi le potentiel de ces techniques dans l’analyse comparative de la diète des mammifères marins. La caractérisation des signatures d’acide gras des proies potentielles et des prédateurs constitue une étape essentielle dans le cheminement menant à une meilleure compréhension de l’écologie alimentaire de ces animaux.Knowledge of diet is an important element for understanding the ecology of species. Currently, there are few techniques to examine the contemporary diet of St. Lawrence belugas considering the precarious status of the population and the rarity of prey remains in the stomach of stranded individuals. Fatty acid analyses of prey and blubber may provide the tools to indicate diet. It was with this purpose that a comparative study of fatty acid profiles was undertaken. As a first step, about 60 potential prey species for belugas were collected in the Estuary and Gulf of St. Lawrence and were examined for their fatty acid profiles. The analysis revealed the need to consider the effects of lipid content, size, season, and sampling location when evaluating species fatty acid profiles in order to improve evaluations of prey profiles of a predator such as the beluga. Blubber fatty acid analyses were subsequently compared between belugas and four species of pinnipeds that are encountered in the Estuary and the Gulf. Species along with other classes such as sex and age could be distinguished on the basis of their fatty acid signatures. A suite of multivariate analyses confirmed the role of diet-linked fatty acids in differentiating the groups, thereby confirming the potential for these techniques to conduct a comparative analysis of diets among these marine mammals. The characterization of fatty acid signatures of potential prey and predators represents essential steps on the path towards a better understanding of trophic ecology in these animals

Diet composition of redfish (Sebastes sp.) during periods of population collapse and massive resurgence in the Gulf of St. Lawrence

Redfish (Sebastes mentella and S. fasciatus) are back at spectacular record high levels in the Gulf of St. Lawrence (GSL) and the effects of this massive resurgence on other components of the food web remain largely unknown. To better understand the trophic implications of the surging redfish biomass within the GSL ecosystem, 3,690 stomachs containing food were collected during two periods: one characterised by low redfish abundance (1993–1999) and the other during a period of record abundance (2015–2019). Taxonomical analysis of stomach contents from individuals of different sizes from three subareas of the GSL was carried out to determine diet composition during both periods. Zooplankton represented the main prey category for small redfish (< 20 cm), which was driven by a predation on amphipods, mostly Themisto sp. in North-East Gulf, in the 1990s and on copepods of the genus Calanus in the deep channels and euphausiids in North-West Gulf in the 2010s. Themisto sp. still dominated the diet of medium (20–30 cm) redfish in the 1990s while the copepods were predominant during the 2010s. Shrimp consumption increased with redfish size and two species were particularly important in large redfish diet (≥ 30 cm) during both periods: pink glass shrimp (Pasiphaea multidentata), mostly in the Laurentian Channel and northern shrimp (Pandalus borealis), especially in North-East Gulf. Redfish predation on shrimp represents a major concern for the dynamics of the northern shrimp which supports a valuable fishery in the GSL but has been declining in abundance since several years. Piscivory was observed in large redfish diet, with capelin (Mallotus villosus) being the major fish prey in the 1990s and redfish (cannibalism) in the 2010s, suggesting density-dependent control at high density of small redfish. By presenting a detailed overview into the redfish diet composition and its temporal variability, the present study offers a first look into the possible future trophic impacts of a resurging groundfish in the GSL ecosystem

Mission: Implausible — Revealing rogue marine species in records across biodiversity data platforms

Online biodiversity platforms publish datasets with graphic tools to help with quality control of submitted records, but more could be done to make the data robust for ecological analyses. Attention has focused mostly on automating tools for obvious errors, including misspelled names and synonyms, dates, or coordinates. However, a manual review of species identifications and distributions may uncover improbable records, such as a species reported in an area far from its usual range, or a rare species found in an area that has many more records of a related species. Examples are shown by constructing checklists in the Northwest Atlantic, using information from the World Register of Marine Species (WoRMS, http://www.marinespecies.org) and the Ocean Biogeographic Information System (OBIS, https://obis.org). Reviewing rare species records revealed some misidentifications, but in other instances, the rare species was valid while it was the commonly reported species that needed correction. Confirmations were obtained by comparing records from different regions, but also across platforms, including photos from observers on iNaturalist Canada (https://inaturalist.ca), genetic analyses on Barcode of Life Data systems (BOLD, http://www.boldsystems.org), and literature in the Biodiversity Heritage Library (BHL, https://www.biodiversitylibrary.org). While this exercise succeeded in validating the marine taxa of a region, it is an obvious candidate for automation in three areas: 1) flagging records of improbable taxa in a region, 2) comparing records with different types of information (e.g., specimen photos, genetic groupings, or literature records), and 3) updating users and providers when records get flagged as unusual or are modified. The first approach could be explored using online graphics tools or R software packages (rOpenSci, https://ropensci.org). The second toolset, comparing records across platforms, is partially realized with some linkages already operating between WoRMS, OBIS, BOLD, BHL, iNaturalist, and the Global Biodiversity Information Facility (GBIF, https://www.gbif.org). The third target will be the most difficult to implement, requiring reliable platform cross-linkages and specimen record identifiers to send notifications of changed status of records to both users and the original data source. Ongoing work is discussed on communicating the need to review records across platforms, with the hope that toolsets will be developed to make this task easier

Biodiversité du secteur marin de la péninsule de Manicouagan : une aire marine protégée en devenir

Le secteur marin situé au large de la péninsule de Manicouagan (700 km2), dont l’écosystème complexe laissait présager une diversité et une productivité importantes, est en voie de devenir une aire marine protégée. La configuration topographique s’apparentant à celle d’un plateau continental et le mélange de l’eau douce des rivières avec les eaux salées de l’estuaire du Saint-Laurent créent des conditions favorables à une diversité de niches écologiques allant des vastes battures de l’estran jusqu’aux eaux profondes à plus de 300 m dans le chenal laurentien. Nous avons caractérisé cette diversité en étudiant le fond marin et les invertébrés benthiques de 2001 à 2008 à l’aide de divers engins d’échantillonnage. Plus de 400 espèces animales ont été recensées. Ces espèces se regroupent en communautés plus ou moins distinctes réparties sur tout le territoire en fonction de la profondeur et de la nature du fond marin. Nous dressons ici un portrait de cette diversité d’espèces benthiques qui habitent l’aire marine de Manicouagan

La collection d’organismes marins de l’Institut Maurice-Lamontagne (Ministère des Pêches et des Océans)

L’Institut Maurice-Lamontagne de Mont-Joli (Québec, Canada) conserve une collection d’organismes marins, principalement de l’estuaire et du golfe du Saint-Laurent mais aussi de l’Arctique canadien. Plus de 1 460 espèces sont présentes parmi les spécimens qui ont été recueillis entre 1900 et 2014 et qui procurent des références taxonomiques et biogéographiques à la communauté scientifique, ainsi que des informations pour le grand public. Cet article présente un résumé de l’historique, de la richesse et de la répartition géographique des spécimens conservés, qui se sont avérés nécessaires pour les travaux du ministère des Pêches et des Océans et d’autres utilisateurs.The Maurice Lamontagne Institute, which is located in Mont-Joli (Québec, Canada), houses a collection of marine organisms originating mainly from the Estuary and Gulf of St. Lawrence, but also from the Canadian Arctic. The collection includes specimens of more than 1460 species that were collected between 1900 and 2014, and these provide taxonomic and biogeographic reference material for to the scientific community, and educational information to the general public. This article summarizes the history, diversity and geographic distribution of the specimens, which have proven important for the work of the Department of Fisheries and Oceans and its affiliates

International megabenthic long-term monitoring of a changing arctic ecosystem: Baseline results

The sustainable development and environmental protection of the Arctic ecosystem is on the agenda globally. The Convention of Biological Diversity (CBD) and the UN Sustainable Development Goals call for conserving at least 10 per cent of coastal and marine areas globally. Management tools to achieve this goal include marine protected areas (MPAs) and “other effective area-based conservation measures” (OECMs) of structural megabenthic organisms (e.g. corals, sea pens, sponges, anemones, etc.). But large areas of the ocean are lacking information about seabed communities. Here we show that this data gap can potentially be filled by collecting data on megabenthic organisms that are “bycatch” (not the target species) on government research vessels monitoring commercial fish and shellfish. For this paper, several Arctic and sub-arctic nations contributed megabenthos data from a total of 12.569 fish assessment trawls and associated bottom water temperature data. The latter outline areas of warm sub-Arctic inflow versus colder Arctic waters, which we align with temperature affinities of community. We also found that maximum levels of shared taxa were higher between Atlantic and Eurasian Arctic Seas than with Pacific Arctic Seas. Areas of high standardized species richness generally, but not everywhere, coincided with areas of high standardized biomass and/or high current velocity and in transition zones between water masses. We did not find that standardized taxon richness declined with latitude (from 60 to 81°N) as has been previously hypothesized. High biomass was generally associated with Arctic outflow shelves and/ or (within-region) colder water masses. We identify areas with high proportions of sessile and upright taxa that may be susceptible to damage by bottom trawl gear, taxa with calcareous skeletons that may be susceptible to ocean acidification, and 'cold-water' taxa that may be most vulnerable to ocean warming. Our results demonstrate the feasibility and value of international collaboration and cooperation in understanding large-scale patterns of Arctic megabenthic communities and providing scientific advice for management of human activities in the global Arctic ecosystem

International megabenthic long-term monitoring of a changing arctic ecosystem: Baseline results

The sustainable development and environmental protection of the Arctic ecosystem is on the agenda globally. The Convention of Biological Diversity (CBD) and the UN Sustainable Development Goals call for conserving at least 10 per cent of coastal and marine areas globally. Management tools to achieve this goal include marine protected areas (MPAs) and “other effective area-based conservation measures” (OECMs) of structural megabenthic organisms (e.g. corals, sea pens, sponges, anemones, etc.). But large areas of the ocean are lacking information about seabed communities. Here we show that this data gap can potentially be filled by collecting data on megabenthic organisms that are “bycatch” (not the target species) on government research vessels monitoring commercial fish and shellfish. For this paper, several Arctic and sub-arctic nations contributed megabenthos data from a total of 12.569 fish assessment trawls and associated bottom water temperature data. The latter outline areas of warm sub-Arctic inflow versus colder Arctic waters, which we align with temperature affinities of community. We also found that maximum levels of shared taxa were higher between Atlantic and Eurasian Arctic Seas than with Pacific Arctic Seas. Areas of high standardized species richness generally, but not everywhere, coincided with areas of high standardized biomass and/or high current velocity and in transition zones between water masses. We did not find that standardized taxon richness declined with latitude (from 60 to 81◦N) as has been previously hypothesized. High biomass was generally associated with Arctic outflow shelves and/ or (within-region) colder water masses. We identify areas with high proportions of sessile and upright taxa that may be susceptible to damage by bottom trawl gear, taxa with calcareous skeletons that may be susceptible to ocean acidification, and ’cold-water’ taxa that may be most vulnerable to ocean warming. Our results demonstrate the feasibility and value of international collaboration and cooperation in understanding large-scale patterns of Arctic megabenthic communities and providing scientific advice for management of human activities in the global Arctic ecosystem

Le concept d’approche écosystémique appliqué à l’estuaire du Saint-Laurent (Canada)

Depuis plusieurs années, le concept d’approche écosystémique est avancé mondialement comme une solution possible aux problématiques de gestion liées à la détérioration des écosystèmes marins et de leurs ressources découlant de l’activité humaine, incluant les pêches, le développement industriel, l’aquaculture, etc. Au Canada, le ministère des Pêches et des Océans a développé en 2007 plusieurs initiatives scientifiques régionales afin de tester différents modèles pour l’application d’une telle approche au soutien de la gestion intégrée de diverses activités humaines qui menacent l’intégrité d’un écosystème. L’estuaire maritime du Saint-Laurent, dans l’est canadien, a constitué le cadre d’une de ces initiatives de recherche écosystémique (IRÉ) qui s’est déroulée de 2007 à 2012. L’estuaire est une région de forte production biologique exposée à une vaste gamme de pressions et d’activités humaines pouvant avoir un impact dommageable sur son intégrité et son utilisation durable. Lors d’ateliers de consultations incluant la participation à la fois de scientifiques et des principaux gestionnaires de cette région, deux priorités communes ont été retenues pour la mise en oeuvre de cette IRÉ, soit : (1) espèces fourragères responsables de la présence du rorqual bleu dans l’estuaire maritime du Saint-Laurent et (2) caractérisation des habitats fréquentés par le béluga du Saint-Laurent. L’objectif général de l’IRÉ de l’estuaire du Saint-Laurent était de développer un cadre opérationnel pour la coordination et l’intégration de projets existants ou des suivis en cours avec des nouveaux projets afin de fournir des informations et des avis scientifiques intégrés (application de l’approche écosystémique) reliés aux deux priorités choisies. Les deux thèmes ont abouti à une évaluation scientifique intégrée documentée dans des avis à caractère écosystémique sur plusieurs enjeux de gestion et objectifs de conservation à l’échelle de l’écosystème. Les résultats ont généré de l’information très pertinente à la gestion du parc marin Saguenay–Saint-Laurent, la mise en oeuvre de plans de rétablissement d’espèces en péril (béluga, rorqual bleu) et l’établissement attendu d’une zone de protection marine dans la région. L’objectif du manuscrit est de décrire les éléments qui ont justifié le choix de l’estuaire maritime du Saint-Laurent comme aire d’étude et de présenter la mise en œuvre et certains résultats intégrateurs de l’initiative de recherche écosystémique dans cette région.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author