Date of Award

Fall 2021

Project Type

Thesis

Program or Major

Biological Sciences

Degree Name

Master of Science

First Advisor

Nathan B Furey

Second Advisor

Nigel E Hussey

Third Advisor

Jennifer A Dijkstra

Abstract

Environments change across space and time, requiring organisms to adapt behaviorally and/or physiologically. In the Arctic, where productivity varies greatly among seasons, many marine species exploit a resource pulse associated with annual ice melt. Melting sea-ice releases zooplankton on and within the ice into open water causing many consumers to migrate with the receding ice; however, resident species may too rely on the ephemeral prey source. Fourhorn Sculpin (Myoxocephalus quadricornis) and Slimy Sculpin (Cottus cognatus) are residents of Tremblay Sound, Nunavut Canada which is known as a seasonally productive system in the Arctic. I characterized the seasonal behavior of sculpin by collecting and identifying stomach contents from 175 sculpin during the ice-free periods of 2017-2019. Other individuals were released with acoustic transmitters (n=119) for year-round monitoring of movements throughout Tremblay Sound. Consumption rates were high, with 33% of individuals consuming >5% of their body mass (mean 4.32%; SE 0.25). Diet composition was dominated by amphipods and krill but both traditional and multivariate analyses showed diets shifted and broadened over the short (~6 weeks) ice-free season and between years. Namely, indicator species analysis revealed significant associations with distinct amphipod genera between years (Gammaracanthus sp. in 2017, Onisimus sp. in 2018). Feeding exploitation corresponded with high rates of activity as several metrics of movement and home range consistently revealed more activity during the ice-free period. Further analyses revealed qualitatively that sculpin showed high site fidelity and were residents within Tremblay Sound year-round, though acceleration and pressure sensors indicate individuals may not be entirely dormant under the ice. Together, showing high levels of activity to feed at high levels while maintaining flexibility in diet composition indicates that sculpin are adapted to exploit ephemeral resources. These physiological and behavioral adaptations are likely important to annual energy budgets and have potential to affect the resilience of sculpin to ongoing climate change in marine Arctic ecosystems.

Download

Share

COinS