A generalized application of the catch-curve regression with comparisons of adult mortality and year-class strength between hatchery-stocked and wild-reared lake trout in US waters of Lake Huron

• Published in: Canadian journal of fisheries and aquatic sciences Vol. 80; no. 10; pp. 1714 - 1722
• Main Authors: He, Ji X, Madenjian, Charles P, Wills, Todd C
• Format: Journal Article
• Language: English
• Published: Ottawa NRC Research Press 01.10.2023; Canadian Science Publishing NRC Research Press
• Subjects: Age; Confidence intervals; Environmental aspects; Hatcheries; Lake trout; Lakes; Mortality; Physiological aspects; Regression analysis; Regression models; Statistical analysis; Trout; United States; United States; Lake Huron; United States > US
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/cjfas-2022-0275

The recently developed approach to estimating the instantaneous total mortality of coded-wire-tagged lake trout (Salvelinus namaycush) is generally applicable to catch-at-age data. We further formalized the technique to objectively incorporate the year-class and year effects into the model structure of catch-curve regression. We used this new method to compare adult mortality and year-class strength between the hatchery-stocked and wild-reared lake trout in US waters of Lake Huron, one of the Laurentian Great Lakes. Model comparisons showed no difference in adult mortality between the hatchery- stocked and wild-reared lake trout. Based on 95% confidence intervals, the estimate of adult mortality using the simple catch- curve regression with average number-at-age was not statistically different from the estimate using the linear mixed model with individual number-at-age of multiple year-classes and sampling years. The linear mixed model, however, also quantified lake trout year-class strength and indicated that since 2003, the increases in recruitment of wild-reared lake trout did not fully compensate for the rapid declines in recruitment of hatchery-stocked lake trout in Lake Huron.