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Upper Sandusky, OH, United States

Faust M.D.,University of Wisconsin - Stevens Point | Faust M.D.,Sandusky Fisheries Research Station | Isermann D.A.,University of Wisconsin - Stevens Point | Luehring M.A.,Great Lakes Indian Fish and Wildlife Commission | And 2 more authors.
North American Journal of Fisheries Management | Year: 2015

Abstract: The growth potential of Muskellunge Esox masquinongy was evaluated by back-calculating growth histories from cleithra removed from 305 fish collected during 1995–2011 to determine whether it was consistent with trophy management goals in northern Wisconsin. Female Muskellunge had a larger mean asymptotic length (49.8 in) than did males (43.4 in). Minimum ultimate size of female Muskellunge (45.0 in) equaled the 45.0-in minimum length limit, but was less than the 50.0-in minimum length limit used on Wisconsin's trophy waters, while the minimum ultimate size of male Muskellunge (34.0 in) was less than the statewide minimum length limit. Minimum reproductive sizes for both sexes were less than Wisconsin's trophy minimum length limits. Mean growth potential of female Muskellunge in northern Wisconsin appears to be sufficient for meeting trophy management objectives and angler expectations. Muskellunge in northern Wisconsin had similar growth potential to those in Ontario populations, but lower growth potential than Minnesota's populations, perhaps because of genetic and environmental differences. © 2015, © American Fisheries Society 2015. Source

Brenden T.O.,Michigan State University | Scribner K.T.,Michigan State University | Bence J.R.,Michigan State University | Tsehaye I.,Michigan State University | And 3 more authors.
North American Journal of Fisheries Management | Year: 2015

Abstract: Genetic stock identification analyses were conducted to determine spawning population contributions to the recreational fishery for Walleyes Sander vitreus in Saginaw Bay, Lake Huron. Two spawning population groups were considered: (1) the Tittabawassee River, which has been identified as the largest source of spawning Walleyes for Saginaw Bay; and (2) an aggregate of six spawning populations from Lake Erie and Lake St. Clair that were found to be genetically similar. Overall, the Lake Erie and Lake St. Clair spawning populations were estimated to comprise approximately 26% of the Walleye recreational harvest in Saginaw Bay during 2008–2009. Contribution levels were similar for the 2 years in which genetic samples were collected. Contributions from the Lake Erie and Lake St. Clair spawning populations to the harvest of age-5 and older Walleyes were greater during summer (31.8%; SE = 6.2%) than during late winter and spring (6.0%; SE = 3.7%). Conversely, contributions from the Lake Erie and Lake St. Clair spawning populations to the harvest of age-3 and age-4 fish were fairly similar between seasons (late winter and spring: 31.2%, SE = 6.7%; summer: 41.7%, SE = 5.6%), suggesting that younger Walleyes migrate earlier or reside in Saginaw Bay for extended periods. Our finding that one-quarter of the Saginaw Bay recreational harvest of Walleyes comprises fish from Lake Erie and Lake St. Clair has important management implications, as policies for one lake may have bearing on the other lake—one of the challenges associated with managing migratory fish species. Fisheries management in the Laurentian Great Lakes has a history of being highly coordinated and cooperative among the states and province bordering the individual lakes. Results from this study suggest that cooperation may need to be expanded to account for fish movement between lakes. Received October 28, 2014; accepted February 11, 2015 © 2015, © American Fisheries Society 2015. Source

Vandergoot C.S.,Sandusky Fisheries Research Station | Vandergoot C.S.,Michigan State University | Brenden T.O.,Michigan State University
Transactions of the American Fisheries Society | Year: 2014

Although the Lake Erie population of Walleyes Sander vitreus exhibits complex spatial structuring, the extent to which population demographics also vary spatially is unknown. Using a spatial tag recovery model, we estimated region- and age-specific mortalities and regional movement probabilities by using recoveries from a jaw tagging study initiated in 1990. The best-performing model based on a comparison of quasi-likelihood Akaike's information criterion values had age-group-specific movement probabilities, age- and region-specific natural mortalities, and age-group- and region-specific annual fishing mortalities. Commercial fishing mortality varied considerably during the study, while recreational fishing mortality was more static. Natural mortality of age-5 and older Walleyes was lower than that of younger fish in all regions, with values ranging from 0.30 to 0.40 for age-4 and younger fish and from 0.13 to 0.27 for age-5 and older fish. In Lake Erie's western basin, natural mortality of age-4 fish was lower than that of age-3 fish. Sensitivity analyses indicated that some natural mortality estimates were sensitive to (1) prior probability distributions assigned to mortality components and (2) assumed movement probabilities in regions where no tagging was conducted. The decline in natural mortality with age in Lake Erie's western basin matches what has been found for other populations, suggesting that such patterns are perhaps common in exploited Walleye populations. Movement probabilities in the western basin were greater than those in the combined central and eastern basins. The mortality rates and movement probabilities estimated in this study should assist in the parameterization and scaling of a spatially explicit Lake Erie Walleye assessment model, the development of which has been recommended for the lake's quota management system. Our study is one of the first to apply a spatial tag recovery model to a freshwater fish population for estimating mortality components. We encourage wider use of this method to improve the understanding of how mortality components and movements vary regionally within freshwater systems. Received March 26, 2013; accepted August 19, 2013. © 2014 Copyright Taylor and Francis Group, LLC. Source

Vandergoot C.S.,Sandusky Fisheries Research Station | Vandergoot C.S.,Michigan State University | Brenden T.O.,Michigan State University
Fisheries Research | Year: 2014

We used stochastic simulations to evaluate accuracy and precision of parameter estimates from spatial tag-recovery models under different combinations of high- and low-reward tagging levels, allocations of tags to different age groups, and patterns in age-specific natural mortalities. Our evaluations were based on Lake Erie walleye (. Sander vitreus), which exhibit complex spatial structuring and support economically important recreational and commercial fisheries. In conducting our evaluations, we assumed inter-regional movements of tagged individuals could be treated as fixed (i.e., known) values. Accuracy and precision of parameter estimates generally stabilized at the mid-range tagging levels that were evaluated, suggesting limited gains would result from tagging more fish. Tag-allocation designs did not have large influences on accuracies of fishing mortalities, selectivities, and reporting rates, but accuracies of natural mortality estimates were sensitive to different designs. A skewed tag-allocation design most often had the best level of accuracy for age-5 and older natural mortalities, whereas proportional and balanced designs most often had the best level of accuracy for age-2 and 3 and age-4 natural mortalities, respectively. Results were far from being consistent, however, with other allocation designs sometimes exhibiting better performance under different factor-level combinations. These same tag-allocation designs resulted in the best precision for natural mortalities for these same age groups and in this regard results were consistent (i.e., did not vary by factor-level combinations). Our simulations help to understand how accuracy and precision of estimates from spatial tag-recovery models can vary with different design features of tagging studies and should provide beneficial insight for designing tagging studies for spatially structured fish populations. © 2014 Elsevier B.V. Source

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