Year class strength and catchability of mountain lake brook trout ...

• Main Author: De Gisi, Joseph S.
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Arctic
• Online Access: https://dx.doi.org/10.14288/1.0074808; https://doi.library.ubc.ca/10.14288/1.0074808

Increased gillnet catch per effort (cpe) of juvenile salmonids occurred following intense exploitation of the adult population, for several studies conducted in mountain and arctic small lakes. Higher cpe may reflect increased catchability or greater numbers, so behavioral or numerical responses cannot be inferred from changes in cpe alone. I used age structured estimation methods, and gillnet depletion data from 1986 to 1992 for seven Sierra Nevada small lake brook trout populations, to reconstruct year class strength and prerecruit (age 1) gillnet catchability prior to and during the experimental removals. I made Walters-Collie (1988) estimates of year class strength for the seven study lakes across the years of the removals. The within-year depletions and available models consistently underpredicted the number of fish remaining in the lake, so estimates did not use the within-year structure of the data. Ageing error correction provided little change in the estimated strength of cohorts produced during the ...