Event Title

Biotic and Abiotic Factors Influencing Walleye Recruitment in Escanaba Lake, Wisconsin from 1958-2013

Mentor 1

Justin VanDeHey

Mentor 2

Josh Raabe

Location

Union 181

Start Date

24-4-2015 10:00 AM

Description

The relationship between adult spawning stock abundance and the number of recruits (juvenile fishes produced) is one of the most important relationships in fisheries management, yet one of the most difficult to estimate due to many other factors influencing the relationship. Walleye Sander vitreus are one of the most popular and intensively managed sportfish in North America. Therefore, understanding the stock-recruit relationship for Walleye is important to help ensure sustainability of Walleye populations. In this study we used Age-0 Walleye abundance as our index of recruitment (recruits), adult Yellow Perch Perca flavescens abundance as an index of potential competitors, Walleye spawning stock abundance (Age-5+) as our index of stock size and May water temperature data as an index of environmental conditions known to affect Walleye survival to try and determine what factors had the largest effects on recruitment. All data were collected from Escanaba Lake from 1958-2013 to develop a multiple factor (multiple predictor variables) stock-recruit model and to determine whether a Ricker stock-recruit relationship was observed. A Ricker stock-recruit relationship suggests that at high spawning stock abundances recruitment is decreased due to cannibalism and at low spawning stock abundances recruitment is reduced due to low abundances of adults. Maximum recruitment is derived from moderate spawning stock abundances. We used Statistical Analysis System (SAS) to estimate parameters for a multiple factor Ricker stock-recruit model. The interaction of May water temperature coefficient of variation (CV) and adult Yellow Perch abundance accounted for 50% of the variation in recruitment. Adult Yellow Perch abundance and spawning stock abundance increased the explained variation to 72% and 79% respectively. This suggests that through the use of three variables we were able to predict nearly 80% of the variation in Walleye recruitment in Escanaba Lake. Other possible variables that may help explain Walleye recruitment could include wind, surface water temperatures, and predator and prey abundances. The development of a stock-recruit model for Walleye in Escanaba Lake can serve as a template that would allow fisheries managers to make better management decisions based on a more accurate estimation of Walleye recruitment.

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Apr 24th, 10:00 AM

Biotic and Abiotic Factors Influencing Walleye Recruitment in Escanaba Lake, Wisconsin from 1958-2013

Union 181

The relationship between adult spawning stock abundance and the number of recruits (juvenile fishes produced) is one of the most important relationships in fisheries management, yet one of the most difficult to estimate due to many other factors influencing the relationship. Walleye Sander vitreus are one of the most popular and intensively managed sportfish in North America. Therefore, understanding the stock-recruit relationship for Walleye is important to help ensure sustainability of Walleye populations. In this study we used Age-0 Walleye abundance as our index of recruitment (recruits), adult Yellow Perch Perca flavescens abundance as an index of potential competitors, Walleye spawning stock abundance (Age-5+) as our index of stock size and May water temperature data as an index of environmental conditions known to affect Walleye survival to try and determine what factors had the largest effects on recruitment. All data were collected from Escanaba Lake from 1958-2013 to develop a multiple factor (multiple predictor variables) stock-recruit model and to determine whether a Ricker stock-recruit relationship was observed. A Ricker stock-recruit relationship suggests that at high spawning stock abundances recruitment is decreased due to cannibalism and at low spawning stock abundances recruitment is reduced due to low abundances of adults. Maximum recruitment is derived from moderate spawning stock abundances. We used Statistical Analysis System (SAS) to estimate parameters for a multiple factor Ricker stock-recruit model. The interaction of May water temperature coefficient of variation (CV) and adult Yellow Perch abundance accounted for 50% of the variation in recruitment. Adult Yellow Perch abundance and spawning stock abundance increased the explained variation to 72% and 79% respectively. This suggests that through the use of three variables we were able to predict nearly 80% of the variation in Walleye recruitment in Escanaba Lake. Other possible variables that may help explain Walleye recruitment could include wind, surface water temperatures, and predator and prey abundances. The development of a stock-recruit model for Walleye in Escanaba Lake can serve as a template that would allow fisheries managers to make better management decisions based on a more accurate estimation of Walleye recruitment.