Date of Award

2000

Publication Type

Doctoral Thesis

Degree Name

Ph.D.

Department

Biological Sciences

Keywords

Biology, Zoology.

Supervisor

Sale, Peter,

Rights

info:eu-repo/semantics/openAccess

Abstract

This study evaluated age-0 yellow perch (Perca flavescens) growth and winter mortality patterns in 18 different lake populations. All analyses attempted to identify if size-dependent patterns in growth and winter survival were present and how they varied among lakes differing by orders of magnitude in surface area. Perch populations were evaluated over short-term (≤3 sequential cohorts) and long-term (≥12 sequential cohorts) periods between 1958 and 1998. Changes in cohort length frequency distributions between the autumn and following spring or differences between observed autumn length distributions and back-calculated end-of-season lengths from otoliths were used to identify and interpret perch winter survival patterns. I observed evidence of size-selective overwinter survival in this study, over both short and long-term periods. When these results are considered with the findings of Post & Evans (1989, Can J Fish Aquat Sci 46, 1958--1968) who studied lakes smaller than the ones sampled in this study, they confirm that the largest members of the age-0 cohorts have the greatest probability for winter survival, independent of lake size or predator community. When these two studies are taken together, a threshold of 60 mm can be identified as the minimum body length required for overwinter survival of the temperate winter in the Great Lakes basin. Maintenance of perch populations in temperate lakes requires age-0 perch to show flexible behaviour and growth rates, because mortality processes in these habitats are strongly dependent on length during the age-0 life stage. Because a linkage was observed between large cohorts of age-0 perch that survived to the second year and asynchronous spawning behaviour in adults influenced by a periodic climate anomaly, the exact mechanism deserves further investigation in other field situations. Selection for, and expression of rapid and opportunistic growth in wide-ranging fish species like perch represents a flexible strategy for survival in seasonally-variable habitats that demand large body size to increase the probability of surviving periods of winter starvation. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2000 .F58. Source: Dissertation Abstracts International, Volume: 62-10, Section: B, page: 4413. Adviser: Peter Sale. Thesis (Ph.D.)--University of Windsor (Canada), 2000.

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