The influence of abiotic factors on gill-net catch rates and the evaluation of mortality rates for yellow perch in southern Lake Michigan

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Authors
Rydell, Joseph J.
Advisor
Lauer, Thomas E.
Issue Date
2008
Keyword
Degree
Thesis (M.S.)
Department
Department of Biology
Other Identifiers
Abstract

I determined differences in yellow perch gill-net catch-per-unit-effort (CPUE) at two depths (10 and 15 m) in the Indiana waters of Lake Michigan during June, July, and August from 1989 to 2006. I evaluated the abiotic factors of water temperature, water clarity, wave height, and wind direction to determine whether they influence the differences in yellow perch CPUE. This study suggests that yellow perch in southern Lake Michigan may select habitat based on water temperature during the summer, moving in response to thermocline changes. We also evaluated mortality rates for two distinct periods (1984-1994 and 2000-2007) in order to identify the response of the population to changes in exploitation. Yellow perch during 1984-1994 (high exploitation) and 2000-2007 (low exploitation) displayed an increase in mortality for fish of harvestable size. In addition, during 2000-2007 (low exploitation) we identified that female yellow perch reached exploitable size earlier in life than males.

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