Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2023
Höfundar / Authors: Stefán Ó. Steingrímsson (1), Nicolas Larranaga (1), Michael A. Galloway (1), Frederic Hadi (1), Krystal L. Mannion (1), Helgi Þ. Thorarensen (1), Laura K. Weir (2).
Starfsvettvangur / Affiliations: 1. Hólar University, Iceland, 2. St. Mary´s University, Canada
Kynnir / Presenter: Stefán Óli Steingrímsson
Water current velocity plays a key role in the habitat selection of stream-dwelling salmonids, and has important implications for their growth, and spatial distribution. Although Arctic charr in streams typically inhabit slow-running waters compared to most stream salmonids, limited effort has been directed towards understanding the driving forces behind their habitat use. Here, we report selected findings from two field experiments that examine how diel activity, feeding behavior, metabolic rate, and growth of 120 (60 per experiment) juvenile Arctic charr, interact with water current velocity. Arctic charr in exp. 1 spent more time feeding each day in fast waters than in slow water, whereas the opposite occurred in exp. 2. Surprisingly, in both experiments, Arctic charr grew faster in fast-running waters than in slower waters, which are believed to be preferred. Moreover, fish in slow waters (i) had access to less drifting prey, (ii) emerged later from shelters, (iii) were more mobile when searching for prey, and (iv) swam slower, than in faster waters. Finally, inhabiting slow, low-energy habitats (v) seems to result in lower standard metabolic rate in Arctic charr, compared to fish using faster waters. In this presentation, we will highlight how behavioral, physiological, and ecological variables can shape the habitat use and growth of Arctic charr in streams.