Date of Award

2011

Degree Type

Thesis

Degree Name

M.A.Sc.

Department

Biological Sciences

First Advisor

Ciborowski, Jan (Biological Sciences)

Keywords

Biology.

Rights

CC BY-NC-ND 4.0

Abstract

Size-selective mortality is common in systems where selective harvesting targets a specific size- or age-class. In general, commercial and recreational fisheries selectively remove the largest and fastest growing individuals, which may have evolutionary consequences. My goals were to examine length-at-age patterns, age at first and full recruitment to the fishery, and to determine if size-selective mortality existed in a commercially and recreationally fished population of walleye in Lake Erie of the Laurentian Great Lakes between 2000 and 2008. Mean fork length-at-age was found to increase from west to east within Lake Erie for age 2 and 3 walleye. However, mean fork-length at age 1 was not statistically different among sampling areas. Walleye first recruited to the fishery at age 1 and were not fully recruited by age 3. Smaller (slower growing) individuals were found to disproportionately survive to older ages than faster-growing fish, indicating that size-selective mortality of larger (faster growing) fish occurred. Size-selective mortality will likely have a negative effect on morphological (i.e., body size) and life history traits.

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