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Utilizing External Features and a Consensus Field-Based Approach to Determine Sex of Lake Michigan Yellow Perch

Author:
Dub, Joshua D., Roswell, Charles R., Czesny, Sergiusz
Source:
North American Journal of Fisheries Management 2017 v.37 no.5 pp. 1107-1111
ISSN:
1548-8675
Subject:
Perca flavescens, demographic statistics, digital images, females, fish, game fish, males, sex ratio, sexual dimorphism, Lake Michigan
Abstract:
Understanding fluctuations in population sex ratios is important for evaluating the effects of changes in population demographics and for making informed management decisions. The Yellow Perch Perca flavescens , an important sport fish in Lake Michigan, undergoes sexually dimorphic growth, likely resulting in differing vulnerabilities to angler harvest. However, sex ratio data from angler-harvested fish have not been collected because of the handling time and intrusiveness of the methods for distinguishing sexes. We utilized digital photographs of the urogenital papilla (UGP) from known-sex Yellow Perch to establish a method whereby UGP shape could be used to rapidly, accurately, and inexpensively determine the sex of Yellow Perch. Overall, 88.1% of Yellow Perch examined were assigned to the correct sex, and the sex ratio estimate of 48:87 (female : male) did not differ significantly from the known sex ratio of 46:89. Classification success was not affected by fish sex, TL, or month of collection. Our results demonstrate accurate, rapid, inexpensive, and nonlethal applicability of this method across a wide range of sizes and geographic and temporal scales. Applying this methodology will permit accurate sex ratio estimates for angler-harvested Yellow Perch, which can be used to better understand harvest composition and its implications for management. Received February 17, 2017; accepted June 9, 2017 Published online August 31, 2017
Agid:
5849383