Preference for nearshore and estuarine habitats in anadromous Arctic char (Salvelinus alpinus) from the Canadian high Arctic (Victoria Island, Nunavut) revealed by acoustic telemetry

Abstract

Abstract:We used an array of fixed acoustic receivers (N = 42) to track the summer marine movements of 121 anadromous Arctic char (Salvelinus alpinus) equipped with acoustic transmitters at three locations in the Cambridge Bay region, where commercial and subsistence fisheries target the species. The timing of transitions between salt and fresh water was influenced by the putative river of origin of tagged individuals, but not by their size or sex. Females, however, were more likely to remain proximate to rivers where they were tagged throughout the summer. A majority of fish migrated west from their rivers of origin, primarily moving between estuarine environments. Individuals occupied estuaries for several days between bouts of marine movement, and these periods of residency coincided with spring tides in some estuaries. We also recorded increased numbers of detections on receivers located less than 1.5 km from the coast, indicating a preference for nearshore habitats. Finally, we report evidence of extensive stock mixing throughout the summer, including at known fishing locations and periods, a finding with implications for fisheries management.Résumé : Les mouvements estivaux en milieu marin de 121 ombles chevaliers (Salvelinus alpinus) anadromes équipées de transmetteur metteur acoustique issus de trois sites de marquages ont été suivis grâce à un réseau de récepteurs acoustiques (N = 42) ancrés dans la région de Cambridge Bay. Les périodes de transition entre les eaux douces et salées étaient influencées par la rivière d'origine des individus, mais pas par leur taille ou leur sexe. Cependant une proportion plus grande de femelles restait près de leur rivière de capture pour tout l'été. Une majorité d'individus ont migré vers l'ouest se déplaçant d'estuaire en estuaire. Ces périodes de résidence en estuaires duraient souvent plusieurs jours, et coïncidaient avec les marées de vives-eaux dans certains estuaires. Dans toute la zone d'étude, les récepteurs situés à moins de 1,5 km de la côte ont enregistré un plus grand nombre de détections, indiquant une préférence pour les habitats côtiers. Finalement, nos données révèlent un mélange des stocks durant la période estivale, notamment dans des zones et périodes de pêches, un résultat ayant d'importantes répercus-sions pour la gestion des pêches.

Genomics and telemetry suggest a role for migration harshness in determining overwintering habitat choice, but not gene flow, in anadromous Arctic Char

“…Of the 21 fish tagged at the Surrey River, 16 returned to the Ekalluk River each year they were detected (76%), while only one fish returned to the Surrey River (5%). We therefore hypothesized that the fish tagged at the Surrey River were likely Ekalluk River fish that we intercepted moving north and west, an interpretation consistent with observations that many Ekalluk River fish visit the Surrey River estuary shortly after their outmigrations to the ocean (Moore et al., ) and also consistent with the population genomic data presented below. Of the 30 fish tagged at the Halokvik River, 28 returned to Halokvik River at least once (93%), and six returned to the Ekalluk River at least once (20%).…”

“…One possibility is that individuals explore a variety of freshwater habitats during their summer migrations and assess their accessibility. Observations of back‐and‐forth movement during homing in other salmonids (Quinn, ) and the regular use of different estuaries by individuals during the summer documented by our telemetry work (Moore et al., ) suggest this is plausible. Another possibility is that the decision of where to overwinter relies in part on collective navigation (i.e.…”

“…While other rivers are also easily accessible (e.g. Freshwater Creek, Jayko River), they are further away from Wellington Bay, and comparatively fewer fish from the Wellington Bay tagging locations travel there (Dempson & Kristofferson, ; Moore et al., ). Given the lack of replication of this environmental axis in the current study, it is impossible to conclude without doubt that migration harshness is the main driver of overwintering habitat selection.…”

Abundance and species diversity hotspots of tracked marine predators across the North American Arctic

“…Moreover, there is a large data gap on movement behaviour of marine fishes compared to marine mammals and seabirds in the Arctic. Ongoing studies by The Ocean Tracking Network have provided insight into the movement ecology of key pelagic and deep‐water fishes (Hussey et al., ; Kessel et al., ; Moore et al., ) with implications for fisheries and conservation management (Barkley et al., ; Hussey et al., ). Continued telemetry studies on Arctic fishes along with other marine predators will further expand our knowledge of the mechanisms and processes that affect Arctic ecosystem structure and function and will improve our understanding of important areas for conservation.…”

Sex matters in massive parallel sequencing: Evidence for biases in genetic parameter estimation and investigation of sex determination systems

“…Sex was determined visually by observation of the gonads for a subset ( n = 174) and based on a genetic assay for another subset ( n = 116), as described in Moore et al. (). In brief, the genetic sex was inferred based on the PCR assay described in Yano et al.…”