The Influence of Temporal and Spatial Variability in Trout-perch (Percopsis omiscomaycus) Whole Organism Characteristics on Monitoring Strategies

• Main Author: Marshall, Stephanie Nicole
• Other Authors: Munkittrick, Kelly, McMaster, Mark, Wrona, Frederick
• Format: Master Thesis
• Language: English
• Published: Graduate Studies 2023
• Subjects: Ecology; Athabasca River; Peace River
• Online Access: https://hdl.handle.net/1880/117547; https://doi.org/10.11575/PRISM/42390

The Environmental Effects Monitoring (EEM) approach in Canada utilizes whole organism characteristics such as body size, growth rates, organ sizes, and fecundity to establish fish performance. There have been a variety of studies that have shown that the optimal timing for measuring fish characteristics varies with reproductive strategy and seasonal timing. As trout-perch (Percopsis omiscomaycus) become more widely used, information on annual variability, as well as local and regional variability will be critical for designing sensitive monitoring programs. We sampled trout-perch over an annual cycle from July 2021 to May 2023 during ice-free months and measured size, age, condition, relative organ size, and sex steroid hormone productivity. Monthly sampling was characterized by the annual reproductive cycle to determine the optimal timing of sampling, and the stability of indicators. Trout-perch were determined to be multiple spawners, with the maximum GSIs for female fish (13.7%) in late May, which is the estimated time of their first spawning of the year. Although a literature review had suggested that the optimal time to sample multiple spawning fish species for evaluating reproductive effects should be 4-6 weeks prior to spawning, this study demonstrated no significant difference in trout-perch EEM endpoints between late September and April. Early fall gonadal development is unusual in multiple spawning species, but suggests that the fall sampling program utilized by the Oil Sands Monitoring program is sufficient for evaluating trout-perch condition. Normal ranges were calculated for condition, relative liver size and relative gonad size for Jumpingpound Creek. These ranges correlated well with 2021 observed ranges for the Peace River, but did not correlate well with historical Peace River data, or with Athabasca River data. Site-specific ranges fit Peace River data better, but still did a poor job for most Athabasca River sites. Higher variability in Athabasca River values was attributed to more ...