Movements of a deep‐water fish: establishing marine fisheries management boundaries in coastal Arctic waters

Abstract

Management boundaries that define populations or stocks of fish form the basis of fisheries planning. In the Arctic, decreasing sea ice extent is driving increasing fisheries development, highlighting the need for ecological data to inform management. In Cumberland Sound, southwest Baffin Island, an indigenous community fishery was established in 1987 targeting Greenland halibut (Reinhardtius hippoglossoides) through the ice. Following its development, the Cumberland Sound Management Boundary (CSMB) was designated and a total allowable catch (TAC) assigned to the fishery. The CSMB was based on a sink population of Greenland halibut resident in the northern section of the Sound. Recent fishing activities south of the CSMB, however, raised concerns over fish residency, the effectiveness of the CSMB and the sustainability of the community-based winter fishery. Through acoustic telemetry monitoring at depths between 400 and 1200 m, and environmental and fisheries data, this study examined the movement patterns of Greenland halibut relative to the CSMB, the biotic and abiotic factors driving fish movement and the dynamics of the winter fishery. Greenland halibut undertook clear seasonal movements between the southern and northern regions of the Sound driven by temperature, dissolved oxygen, and sea ice cover with most fish crossing the CSMB on an annual basis. Over the lifespan of the fishery, landfast ice cover initially declined and then became variable, limiting accessibility to favored fisher locations. Concomitantly, catch per unit effort declined, reflecting the effect of changing ice conditions on the location and effort of the fishery. Ultimately, these telemetry data revealed that fishers now target less productive sites outside of their favored areas and, with continued decreases in ice, the winter fishery might cease to exist. In addition, these novel telemetry data revealed that the CSMB is ineffective and led to its relocation to the entrance of the Sound in 2014. The community fishery can now develop an open-water fishery in addition to the winter fishery to exploit the TAC, which will ensure the longevity of the fishery under projected climate-change scenarios. Telemetry shows great promise as a tool for understanding deep-water species and for directly informing fisheries management of these ecosystems that are inherently complex to study.

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.…”

Environmental factors influence the detection probability in acoustic telemetry in a marine environment: results from a new setup

“…migration routes, spatio-temporal habitat use and movement behaviour of key species) in these environments has significantly improved in recent years. This knowledge provides a scientific basis for fisheries management (Hussey et al, 2017), species conservation, marine spatial planning (Abecasis et al, 2014;Afonso et al, 2016) and environmental impact assessment (Winter et al, 2010;Reubens et al, 2014).…”

Transient movements of a deep‐water flatfish in coastal waters: Implications of inshore‐offshore connectivity for fisheries management

“…In the current study, Greenland halibut were tagged within the 22 km zone prioritized for the development of small‐scale community fisheries. The majority of these tagged fish did not exhibit the level of residency previously reported in fjord habitats (Boje, ; Boje et al., ; Hussey et al., ), but were instead highly migratory, using the coastal area in the late summer months then exiting into the offshore as ice formed. Variability in movement measures was observed among individuals while in coastal waters as a result of differing movement rates and residency times within sections of the coastal environment.…”

“…In the Canadian Arctic, mark–recapture work in Cumberland Sound revealed that fish tagged in the northern end of the Sound were also resident, while fish tagged at the entrance were found to migrate to both inshore and offshore areas (Treble, ). More recently, acoustic telemetry found that fish in Cumberland Sound moved from north to south on a seasonal basis (Hussey et al., ), undertaking movements similar to fish in Disko Bay (Boje et al., ), but with some evidence for emigration. While most studies on Greenland halibut have suggested high levels of residency within coastal deep water fjords, this study suggests that transient movements can occur during the summer–fall period.…”

“…If a winter fishery were developed through the ice in Scott Inlet (and potentially other coastal communities), the intermittently resident Greenland halibut would be the primary target. Ice fisheries, however, have an uncertain future in the Arctic as climate change is driving unpredictable weather and ice conditions, complicating access to fishing grounds (Hussey et al., ). In this scenario, the development of a summer boat‐based fishery in Scott Inlet would be more resilient to climate change but would ultimately catch fish of both migratory types, including the transients that are also caught in the offshore.…”