Under-ice distribution of polar cod Boreogadus saida in the central Arctic Ocean and their association with sea-ice habitat properties

• Published in: Polar biology 2016-06, Vol.39 (6), p.981-994
• Main Authors: David, Carmen, Lange, Benjamin, Krumpen, Thomas, Schaafsma, Fokje, van Franeker, Jan Andries, Flores, Hauke
• Format: Article
• Language: English
• Subjects: Animal populations; Aquatic Ecology and Water Quality Management; Aquatische Ecologie en Waterkwaliteitsbeheer; Biomedical and Life Sciences; Climate change; Cod; Ecology; Ecosystemen; Environmental changes; Fish; Fishes; Genetic vectors; Habitats; Ice drift; IMARES Ecosystemen; IMARES Onderzoeksformatie; Leerstoelgroep Aquatische ecologie en waterkwaliteitsbeheer; Life Sciences; Microbiology; Ocean; Oceanography; Oceans; Onderzoeksformatie; Original Paper; Plant Sciences; Salinity; Sea ice; Zoology
• ISSN: 0722-4060; 1432-2056
• DOI: 10.1007/s00300-015-1774-0

In the Arctic Ocean, sea-ice habitats are undergoing rapid environmental change. Polar cod ( Boreogadus saida ) is the most abundant fish known to reside under the pack-ice. The under-ice distribution, association with sea-ice habitat properties and origins of polar cod in the central Arctic Ocean, however, are largely unknown. During the RV Polarstern expedition ARK XXVII/3 in the Eurasian Basin in 2012, we used for the first time in Arctic waters a Surface and Under Ice Trawl with an integrated bio-environmental sensor array. Polar cod was ubiquitous throughout the Eurasian Basin with a median abundance of 5000 ind. km −2 . The under-ice population consisted of young specimens with a total length between 52 and 140 mm, dominated by 1-year-old fish. Higher fish abundance was associated with thicker ice, higher ice coverage and lower surface salinity, or with higher densities of the ice-amphipod Apherusa glacialis . The fish were in good condition and well fed according to various indices. Back-tracking of the sea-ice indicated that sea-ice sampled in the Amundsen Basin originated from the Laptev Sea coast, while sea-ice sampled in the Nansen Basin originated from the Kara Sea. Assuming that fish were following the ice drift, this suggests that under-ice polar cod distribution in the Eurasian Basin is dependent on the coastal populations where the sea-ice originates. The omnipresence of polar cod in the Eurasian Basin, in a good body condition, suggests that the central Arctic under-ice habitats may constitute a favourable environment for this species survival, a potential vector of genetic exchange and a recruitment source for coastal populations around the Arctic Ocean.