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Climate change is impacting marine ecosystems throughout the circumpolar Arctic, altering seasonal habitats and the food bases for fishes, seabirds, and marine mammals. Arctic and Subarctic regions provide resources for resident species and for species that migrate to the north from more southerly regions. Changes in northerly latitudes thus impact endemic as well as non-endemic animals. Herein, we review what is known about climate-driven changes in the migration patterns of Arctic and Subarctic marine vertebrates, including: 1) Arctic residents with seasonal movements – those fishes, seabirds, and marine mammals that complete their entire life cycle within the Arctic but exhibit seasonal movements; 2) Breeding migrants – many seabirds enter the Arctic to breed and subsequently migrate south in the fall; and 3) Summer visitors for feeding – certain species of boreal fishes, seabirds and marine mammals arrive during the northern summer to feed on abundant prey though they breed elsewhere. Migratory movements are often driven by the timing and extent of sea ice, which defines suitable habitat for some animals and limits access to open water and prey for others. Longer open-water seasons, warmer ocean temperatures, and stronger winds have resulted in earlier production blooms in spring and often, extended open-ocean plankton blooms into late summer, resulting in altered prey types and distributions. A common thread among taxa is that shifts in distribution and timing of migrating animals indicate they are traveling farther north, or shifting longitudinally, and migrations are occurring over longer seasonal time frames. Species performing multiple lifetime migrations or long-distance migrants may need to adjust migration timing or routing iteratively to match changes in marine productivity. Altered animal distributions or phenology, and reduced sea ice, affects access to animals that are critical nutritional, economical, and cultural components of Indigenous people's lives in the Arctic. Ongoing changes challenge the resilience and adaptability of Arctic people and ecosystems, and will require adaptive research and management approaches. [ABSTRACT FROM AUTHOR]

Objective: Estimates of Pacific salmon Oncorhynchus spp. stock composition in coastal fishery harvests are needed to balance fishing opportunities against conservation. Catch partitioning in some small‐scale fisheries can be hindered by insufficient resolution of modern stock classification tools (e.g., genetic stock identification). Methods: We used acoustic telemetry to investigate the stock composition of commercial landings in the Norton Sound district of Alaska by mimicking local fisheries to capture and tag 578 Coho Salmon O. kisutch in the contiguous Shaktoolik and Unalakleet commercial subdistricts over two seasons. Result: In total, 341 individuals that were last detected in demarcated spawning areas were assigned to a stock of origin based on putative natal site fidelity. Sex, location of capture, and timing of capture were predictors of stock membership. Models that were fitted to commercial harvest data from the project years (2020 and 2021) estimated that 32.9% of the Shaktoolik subdistrict catch was Shaktoolik stock, 51.5% was Unalakleet stock, and the remainder consisted of other transitory stocks. Conversely, 86.7% of landed Coho Salmon in the Unalakleet subdistrict were Unalakleet stock, whereas the Shaktoolik stock and transitory stocks made up less than 10%, respectively. Conclusion: These findings suggest that coastal salmon fisheries in Norton Sound have access to a variable mixture of stocks whose unique characteristics can be leveraged to examine the effects of directed harvest effort on stock health and diversity. Impact statementAcoustic telemetry identifies unique characteristics of adult Coho Salmon that can be used to differentiate among stocks in coastal mixed fisheries, allowing scrutiny of respective relationships with directed harvest effort. [ABSTRACT FROM AUTHOR]

Archival tags can be attached to fish to collect environmental data, usually temperature and pressure (converted to depth) at a minimum, and individual events characterized by changes in such environmental [...]

Bycatch of Pacific halibut (Hippoglossus stenolepis) limits many trawl fisheries in Alaska and greatly concerns stakeholders from local communities and fisheries that rely on Pacific halibut. To reduce Pacific halibut mortality, trawlers in the Bering Sea that target flatfish have been developing expedited release procedures to sort Pacific halibut from catches earlier than current regulations allow, while continuing accurate bycatch accounting. We studied survival rates of released Pacific halibut from three trawlers by deploying accelerometer-equipped pop-up satellite archival tags (PSATs) on 160 fish handled under expedited procedures. PSATs recorded and transmitted two metrics indicating swimming activity every 2 h while attached to the fish (for up to 60 days). Analysis of the resulting survival outcomes largely validated current survival-estimation methods, based on structured viability assessments, and found that longer fish length, shorter duration of air exposure, and shorter duration of trawl tow improved predicted Pacific halibut survival. Differences in these results were detected among vessel trips and species targeted by trawling. PSATs provided detailed data from nearly all tagged fish, while exposing fish to conditions experienced by normal releases. Les prises accessoires de fletan du Pacifique (Hippoglossus stenolepis) restreignent de nombreuses peches au chalut de l'Alaska et preoccupent grandement les parties prenantes de collectivites locales et des peches qui dependent du fletan du Pacifique. Afin de reduire la mortalite des fletans du Pacifique, les chalutiers de la mer de Behring qui ciblent les poissons plats elaborent des procedures de remise a l'eau acceleree pour extraire les fletans du Pacifique des prises plus rapidement que ce que permet la reglementation actuelle, tout en continuant de denombrer les prises accessoires avec exactitude. Nous avons etudie les taux de survie de fletans du Pacifique remis a l'eau par trois chalutiers en deployant des etiquettes satellites autodetachables a archivage (PSAT) sur 160 poissons manipules en suivant des procedures accelerees. Les PSAT enregistraient et transmettaient deux mesures de l'activite de nage pour chaque periode de 2 h pendant qu'elles demeuraient fixees aux poissons (jusqu'a 60 jours). L'analyse des donnees sur la survie en decoulant valident en bonne partie les methodes d'estimation de la survie actuelles reposant sur des evaluations structurees de la viabilite et revele qu'une plus grande longueur du poisson, une exposition a l'air plus courte et une plus courte duree du trait de chalut ameliorent toutes la survie predite des fletans du Pacifique. Des differences dans ces resultats sont observees entre les sorties de navire et les especes ciblees par le chalutage. Les PSAT ont fourni des donnees detaillees sur presque tous les poissons etiquetes, alors que les poissons etaient exposes a des conditions typiques de remises a l'eau normales., Introduction The eastern Bering Sea shelf is one of the most extensive and productive flatfish habitat regions in the world. It has >0.5 million [km.sup.2] of sand and mud substrates [...]

Throughout the northern extent of its range, Chinook salmon (Oncorhynchus tshawytscha) adult returns have been in decline for over a decade, leading to severe harvest restrictions on subsistence, commercial, and recreational fisheries. In addition to these overall declines in abundance, changes in size structure and age structure, including a proportional decrease of older age classes returning to spawn, suggest that late-stage marine mortality for this species may be more frequent than currently assumed. To examine this late-stage mortality hypothesis, we examined diagnostic evidence of predation on large (57-100 cm fork length) Chinook salmon (n = 33) from depth, temperature, and light records collected during recent satellite tagging research. Satellite tags provided evidence of predation on tagged Chinook salmon by salmon sharks (Lamna ditropis) (n = 14), marine mammals (n = 2), ectothermic fish(es) (n = 3), and unidentified predators (n = 5) in the Bering Sea and Gulf of Alaska. High mortality rates in this study suggest that fisheries scientists should consider that late-stage mortality by marine apex predators may be shaping this species' abundance and demographics. A la grandeur de l'ocean Pacifique nord, les retours de saumons chinooks adultes (Oncorhynchus tshawytscha) sont en baisse depuis plus d'une decennie, ce qui se traduit par d'importantes restrictions imposees aux peches commerciales, sportives et de subsistance. En plus de ces baisses d'abondance globales, des changements de la structure par taille et par age, dont une diminution proportionnelle des classes d'age plus vieilles qui reviennent frayer, indiqueraient que la mortalite tardive en mer de cette espece pourrait etre plus grande que ce qui est actuellement presume. Afin d'examiner cette hypothese de mortalite tardive, nous avons examine des preuves diagnostiques de predation de grands (longueur a la fourche : 57-100 cm) saumons chinooks (n = 33) a partir de donnees sur la profondeur, la temperature et la lumiere recueillies dans le cadre d'etudes recentes employant des etiquettes satellites. Ces dernieres fournissent des preuves de la predation de saumons chinooks etiquetes par des taupes du Pacifique (Lamna ditropis) (n = 14), des mammiferes marins (n = 2), des poissons ectothermes (n = 3) et des predateurs non identifies (n = 5) dans la mer de Behring et le golfe d'Alaska. Les taux de mortalite eleves observes dans le cadre de cette etude donnent a penser que les scientifiques specialistes des peches devraient envisager la possibilite que la mortalite tardive causee par des superpredateurs marins puisse moduler l'abondance et la demographie de cette espece. [Traduit par la Redaction], Introduction Under the traditional view of Pacific salmon (Oncorhynchus spp.) population dynamics, it is generally assumed that once a juvenile has survived ocean entry and its first ocean winter, mortality, [...]

Interactions between spatial dynamics and stock structure in marine fishes have largely focused on stocks in decline; stock structure is rarely re-visited for expanding species. Here, the spatial ecology of Atlantic halibut (Hippoglossus hippoglossus L.), managed as four stocks in the Northwest Atlantic, is reviewed. Halibut collapsed under high exploitation in the mid-19th century, but the Canadian fisheries value has increased seven-fold since the early 2000s. Atlantic halibut's thermal habitat has increased due to warming, possibly contributing to its expansion. Genomic evidence differentiates two populations in the four management units, whereas there is non-genetic spatial structure within each of the stock boundaries. There are different core juvenile areas and a diversity of spawning migration patterns influenced by timing, fish size, maturity state, and distance between summer-feeding and over-wintering habitats. From tagging studies, multiple estimates of median distance at recapture (⁓3-90 km) are much less than the spatial domain of each stock. Growth rates are faster in the warmer south, as predicted by growing degree day. The current perspective of Atlantic halibut spatial structure is that there are two distinct populations, and within each, there are subpopulations composed of multiple migratory contingents. The level of mixing on common spawning grounds both among and within subpopulations is only partly understood. [ABSTRACT FROM AUTHOR]

Abstract--We evaluated light-based geolocation estimates from pop-up satellite tags in high latitudes because some of the largest fisheries in the world are in areas where this technique has not been [...]