Depth and temperature preferences of the deepwater flatfish Greenland halibut Reinhardtius hippoglossoides in an Arctic marine ecosystem

Abstract

Little is known about the movement of Arctic marine fish, particularly benthic species, despite growing pressure from commercial fisheries and a changing climate. The Greenland halibut Reinhardtius hippoglossoides lives in the deep, cold waters of the Arctic, North Atlantic and Pacific Oceans where it represents an important commercial fish species and a significant prey resource for whales and sharks. To investigate movement, depth and temperature preferences of Greenland halibut, 9 large (83 to 95 cm fork length) individuals were tagged with pop-off archival transmitting tags in Cumberland Sound, Baffin Island in August 2010 to record data for 70, 100 and 300 d. While all tags reported back, 7 tags provided the bulk of the data, transmitting (mean ± SD) 67 ± 7% of the data collected. Greenland halibut exhibited strong site fidelity to localised deep areas (900 to 1400 m), but ranged between ~400 and 1400 m, with all tags poppingoff within 27 km of the tagging location. Mean depth was 1048 ± 112 m (n = 7) during the ice-free season and 823 ± 121 m (n = 2) during the ice-covered season. Temperature occupied by Greenland halibut from August until June ranged from 1.3 to 2.7°C (mean ± SD: 2.2 ± 0.01°C). A mixedeffect model found preferred depth did not vary within a diel cycle, but did change among months. Seasonal movements coincided with ice cover, but further work is needed to clarify this relationship and determine the extent and timing of these movements within and beyond Cumberland Sound. © Inter-Research and Fisheries and Oceans Canada 2012.