Seasonal Movement Patterns and Habitat Use of Brook Trout Salvelinus fontinalis and Brown Trout Salmo trutta in North Central Pennsylvania

Open Access
Author:
Smith, Lori A
Graduate Program:
Wildlife and Fisheries Science
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
December 10, 2013
Committee Members:
  • Tyler Wagner, Thesis Advisor
Keywords:
  • brook trout
  • brown trout
  • movement
  • habitat use
  • genetics
  • spawning
  • winter
Abstract:
The eastern Brook Trout Salvelinus fontinalis faces a variety of threats largely due to anthropogenic alterations to the landscape and climate change. However, one threat that has implications for Brook Trout population management is the introduction of non-native Brown Trout Salmo trutta, as potential negative impacts of Brown Trout on Brook Trout populations have been documented. For resource management agencies, understanding the temporal and spatial movement patterns and habitat requirements of any species is essential for conserving existing populations and restoring habitats that once supported self-sustaining populations. I employed radio biotelemetry to quantify movement and habitat use of Brook Trout and Brown Trout from September 2012 through February 2013. I equipped 55 Brook Trout and 45 Brown Trout, distributed among five interconnected streams in North Central Pennsylvania, with radio-transmitters. To identify potential relationships between movement and covariates, I used generalized additive mixed models. Thalweg profiles of the streams were also surveyed to quantify available residual pool habitat and I used discrete choice models with random effects to evaluate Brook and Brown Trout habitat use. To corroborate observations in Brook Trout movement made through radio-tracking, Brook Trout fin clips were taken for microsatellite analysis. Average total movement was greater for Brown Trout (2,924 ± 4,187 m) than for Brook Trout (1,769 ± 2,194 m). Maximum net movement was 10,317 m and 11,273 m completed by a Brook Trout and Brown Trout, respectively. Results indicated a large amount of among-fish variability in movement of both species with the majority of movement coinciding with the on-set of the spawning season and increases in stream flow. Microsatellite analysis revealed consistent findings to those in radio-tracking, indicating a moderate to high degree gene flow among study populations. There was an overall preference for pool versus non-pool habitats; however, habitat use of pools was non-linear over time. Brook Trout displayed a greater preference for deep (0.33-1.5 m deep) pool habitats over shallow (0.1-0.32 m deep) pool and non-pool habitats. Conversely, Brown Trout selected for all pool habitat categories similarly. Habitat use of both species was found to be scale dependent. At smaller spatial scales (50 m), habitat use was primarily related to time of year and fish size. However, at larger spatial scales (250 m and 450 m) habitat use varied over time according to the study stream a fish was located. Maximum water depth, length of cover and average water velocity occupied was time-dependent, with Brook and Brown trout occupying shallower maximum water depth and smaller lengths of cover through the spawning season, and increased average water velocity throughout the study. Brown Trout were also found to occupy deeper maximum water depths and greater lengths of cover in relation to Brook Trout. Variations in seasonal movement patterns and habitat use of Brook and Brown Trout highlight the importance for management agencies to consider a diversity of in-stream habitat features and stream connectivity when restoring and protecting habitats and populations of Brook Trout.