BROOK TROUT HABITAT SELECTION AND MOVEMENT RESPONSE TO CRITICALLY HIGH TEMPERATURES IN FRAGMENTED STREAM NETWORKS

Author

Corey Pelletier, University of Rhode IslandFollow

Date of Award

2023

Degree Type

Thesis

Degree Name

Master of Science in Biological and Environmental Sciences (MSBES)

Specialization

Ecology and Ecosystem Sciences

Department

Natural Resources Science

First Advisor

Graham Forrester

Abstract

The Eastern Brook Trout (Salvelinus fontinalis) is a cold-water obligate fish species that is losing habitat across its native range. Increases in water temperature resulting from climate change and anthropogenic influences are causing declines in distribution and this trend is expected to accelerate. The ability of Brook Trout to survive and adapt to increasing temperatures may be limited by physical barriers, such as natural waterfalls, manmade dams, and perched culverts, that are scattered throughout watersheds in the native range. While temperature effects on Brook Trout and other salmonids have been well documented, few research studies have focused on habitat selection and movement in streams with dispersal barriers and environmentally stressful conditions. We aimed to quantify the behavioral response (movement) and habitat selection of Brook Trout during high water temperatures in streams with physical barriers that may function as barriers to dispersal. We implanted VHF radio tags in 75 native Brook Trout and used radio telemetry to track them from June through August in Rhode Island, United States. We selected sites that varied in thermal profile and distance between physical barriers. Study sites were tracked weekly and habitat data were collected at both random locations and focal points of relocated Brook Trout. We used a habitat use- availability framework to estimate habitat selection and compared displacement and movement rates by site. We developed a resource selection function to estimate probability of habitat use for a subset of uncorrelated variables. Movement rates and displacement varied significantly by site, yet Brook Trout selected for similar habitat variables across sites. We found Brook Trout selected for temperature in the warmest sites but not in sites that were cooler, despite periodic high temperature events. In all study sites, Brook Trout consistently selected for greater depth and closer proximity to in-stream cover. Our findings will help managers prioritize habitat restoration and protection at scales ranging from individual habitat units to the watershed scale.

Recommended Citation

Pelletier, Corey, "BROOK TROUT HABITAT SELECTION AND MOVEMENT RESPONSE TO CRITICALLY HIGH TEMPERATURES IN FRAGMENTED STREAM NETWORKS" (2023). Open Access Master's Theses. Paper 2362.
https://digitalcommons.uri.edu/theses/2362