Marine temperature and depth use by anadromous arctic char correlates to body size and diel period

Ingeborg M. Mulder*, Corey J. Morris, J. Brian Dempson, Ian A. Fleming, Michael Power

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)

Abstract

Acoustic and archival telemetry were used to study the marine movements of 115 anadromous Arctic char (Salvelinus alpinus) at two sites in southern Labrador, Canada, in relation to daily variation in temperature and depth use, body size, and their effects on marine activity patterns. Although evidence varied between locations, Arctic char generally utilized ambient water temperatures available in the upper water column, possibly in aid of physiological processes such as digestion, whereas deeper waters were suggested to be used for feeding purposes. Size-dependent thermal preferences were evident, with larger individuals utilizing cooler water temperatures (8.5 °C) compared with smaller individuals (9.5 °C), a pattern suggestive of ontogenetic changes in thermal habitat use for the purposes of growth maximization. Diurnal patterns of diving activity were interpreted to reflect the vertical migration of prey items and (or) the visual capabilities of Arctic char. Dive duration was dependent on body size and external body temperature with smaller individuals performing shorter dives in colder water temperatures (<1 min at 5 °C) than larger fish (~2 min at 5 °C), likely to maintain their core temperature and abilities to both effectively capture prey and avoid predation.

Original languageEnglish
Pages (from-to)882-893
Number of pages12
JournalCanadian Journal of Fisheries and Aquatic Sciences
Volume77
Issue number5
DOIs
Publication statusPublished - 2020

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