Vertical segregation of age-0 and age-1+ polar cod (Boreogadus saida) over the annual cycle in the Canadian Beaufort Sea

Geoffroy, Maxime; Majewski, Andrew; Leblanc, Mathieu; Gauthier, Sylvie; Walkusz, Wojciech; Reist, James D.; Fortier, Louis

doi:10.1007/s00300-015-1811-z

Cited by 73 publications

(80 citation statements)

References 49 publications

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“…Differences in length and sex of belugas harvested in Ulukhaktok relative to the Mackenzie Estuary may reflect sexual segregation of habitat use within their summer range (Loseto et al 2006) and/or may reflect current harvest practices Waugh et al 2018). For example, community hunting bylaws provide guidance to avoid hunting females due to calving activity in the Mackenzie Estuary, and no such bylaws exist for Ulukhaktok (FJMC 2013).…”

Section: Beluga Demographicsmentioning

confidence: 99%

“…Over 30 whales were harvested with 28 whales sampled from Ulukhakok (n = 26) and Sachs Harbour (n = 2). Prior to this event, only opportunistic subsistence harvests have occurred in the vicinity of these communities, with just seven whales landed from 2000to 2012(FJMC 2013. The EBS beluga visit offshore waters following their summer aggregation period in the Mackenzie Estuary .…”

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confidence: 99%

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Diet and feeding observations from an unusual beluga harvest in 2014 near Ulukhaktok, Northwest Territories, Canada

et al. 2018

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The Eastern Beaufort Sea (EBS) beluga (Delphinapterus leucas) population are an important traditional food for the Inuit of the Inuvialuit Settlement Region, Northwest Territories (NT) Canada. In 2014, over 30 beluga whales were harvested at Ulukhaktok, NT, the first occurrence of a large harvest in the area on record. Unlike observations from the established beluga harvest monitoring program in the Mackenzie Estuary, these belugas had numerous prey and prey items in their stomachs. Our study objectives were to combine traditional and local knowledge (TLK) from beluga hunters with the analysis of dissected stomachs to identify EBS beluga diet, feeding behaviour, as well as gain insights into potential drivers of the event. TLK holders witnessed foraging behaviors such as herding schools of fish. Stomach dissections revealed Sandlance (Ammodytes sp.) to be the predominant prey species, comprising 90% of identified otoliths, occurring in 92% of stomachs. The low presence of Arctic Cod (Boreogadus saida), a preferred prey types, raised questions about prey availability/accessibility and if alternative prey types can sustain beluga energetic needs. Based on interviews of TLK holders, avoidance of noise due to human activity, killer whale presence, and shifts in prey were factors that may have led to the increased beluga sightings near Ulukhaktok, NT.

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Section: Beluga Demographicsmentioning

confidence: 99%

mentioning

confidence: 99%

Diet and feeding observations from an unusual beluga harvest in 2014 near Ulukhaktok, Northwest Territories, Canada

et al. 2018

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“…Eggs are spawned and hatch under the ice (Rass, 1968), and larvae are often found under the ice near river plumes, which they may use as a thermal refuge during winter (Bouchard and Fortier, 2011), and as a feeding habitat during spring (Fortier et al, 1996). Larvae remain in the upper water column until the end of their first summer, before descending to deeper layers or to the bottom (Geoffroy et al, 2011(Geoffroy et al, , 2016. However, juveniles may also remain pelagic or associated with sea ice (Lønne and Gulliksen, 1989;Ajiad et al, 2011;Gradinger and Bluhm, 2004;David et al, 2016).…”

Section: Impacts Of Advection On Fish Populations In the Arcticmentioning

confidence: 99%

Advection in polar and sub-polar environments: Impacts on high latitude marine ecosystems

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Arrigo

et al. 2016

Progress in Oceanography

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a b s t r a c tWe compare and contrast the ecological impacts of atmospheric and oceanic circulation patterns on polar and sub-polar marine ecosystems. Circulation patterns differ strikingly between the north and south. Meridional circulation in the north provides connections between the sub-Arctic and Arctic despite the presence of encircling continental landmasses, whereas annular circulation patterns in the south tend to isolate Antarctic surface waters from those in the north. These differences influence fundamental aspects of the polar ecosystems from the amount, thickness and duration of sea ice, to the types of organisms, and the ecology of zooplankton, fish, seabirds and marine mammals. Meridional flows in both the North Pacific and the North Atlantic oceans transport heat, nutrients, and plankton northward into the Chukchi Sea, the Barents Sea, and the seas off the west coast of Greenland. In the North Atlantic, the advected heat warms the waters of the southern Barents Sea and, with advected nutrients and plankton, supports immense biomasses of fish, seabirds and marine mammals. On the Pacific side of the Arctic, cold waters flowing northward across the northern Bering and Chukchi seas during winter and spring limit the ability of boreal fish species to take advantage of high seasonal production there. Southward flow of cold Arctic waters into sub-Arctic regions of the North Atlantic occurs mainly through Fram Strait with less through the Barents Sea and the Canadian Archipelago. In the Pacific, the transport of Arctic waters and plankton southward through Bering Strait is minimal.In the Southern Ocean, the Antarctic Circumpolar Current and its associated fronts are barriers to the southward dispersal of plankton and pelagic fishes from sub-Antarctic waters, with the consequent evolution of Antarctic zooplankton and fish species largely occurring in isolation from those to the north. The Antarctic Circumpolar Current also disperses biota throughout the Southern Ocean, and as a result, the biota tends to be similar within a given broad latitudinal band. South of the Southern Boundary of the ACC, there is a large-scale divergence that brings nutrient-rich water to the surface. This divergence, along with more localized upwelling regions and deep vertical convection in winter, generates elevated nutrient levels throughout the Antarctic at the end of austral winter. However, such elevated nutrient levels do not support elevated phytoplankton productivity through the entire Southern Ocean, as iron concentrations are rapidly removed to limiting levels by spring blooms in deep waters. However, coastal http://dx

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“…The shift to benthic prey presumably reflects ontogenetic shifts in vertical distribution as larger juveniles descend in the water column toward the bottom or to join older fish in an epipelagic layer (Geoffroy et al 2016). The vertical separation between young-of-year and older fish, and a general increase in body size with depth (Geoffroy et al 2016), limits cannibalism, which is relatively rare in polar cod in the Pacific Arctic (Rand et al 2013;Gray et al 2016;Majewski et al 2016) compared to other gadids such as walleye pollock (Gadus chalcogrammus) in the Bering Sea (Bailey 1989).…”

Section: Role In Food Webmentioning

confidence: 99%

“…The remaining 12 papers describe studies on various aspects of polar cod only. These include studies of ecotoxicology (Bakke et al 2016), population genetics (Madsen et al 2016), distribution and habitat use (Astthorsson 2016;Crawford 2016;David et al 2016;Geoffroy et al 2016;Kessel et al 2016;Kono et al 2016), diets of juveniles and adults (Gray et al 2016;Majewski et al 2016;Nakano et al 2016) and reproductive biology . Combined, the current special issue is, at least in the western scientific literature, so far the largest single step forward in our understanding of the ecology, life history and distribution of Arctic gadids in a changing Arctic.…”

Section: Introductionmentioning

confidence: 99%

The ecology of gadid fishes in the circumpolar Arctic with a special emphasis on the polar cod (Boreogadus saida)

et al. 2016

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Vertical segregation of age-0 and age-1+ polar cod (Boreogadus saida) over the annual cycle in the Canadian Beaufort Sea

Cited by 73 publications

References 49 publications

Diet and feeding observations from an unusual beluga harvest in 2014 near Ulukhaktok, Northwest Territories, Canada

Diet and feeding observations from an unusual beluga harvest in 2014 near Ulukhaktok, Northwest Territories, Canada

Advection in polar and sub-polar environments: Impacts on high latitude marine ecosystems

The ecology of gadid fishes in the circumpolar Arctic with a special emphasis on the polar cod (Boreogadus saida)

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