This study assessed exploitation and evaluated management options for walleye, Sander vitreus (Mitchill), in Glen Elder Reservoir, Kansas. A total of 2429 walleye varying from 240 to 687 mm was tagged with Carlin dangler tags during 2000-2003. After correcting for tag loss and non-reporting, exploitation of walleye was estimated as 68.3%. More than 85% of the tagged walleye were harvested during April to June and 75% were harvested within 6 months after tagging. A Beverton-Holt yield-per-recruit model was used to evaluate six minimum length limits varying from 250 to 610 mm. Given current exploitation rates, population demographics and harvest regulations (381-mm minimum length limit), the walleye population is probably experiencing recruitment overfishing. Model results suggested that a 610-mm minimum length limit would be required to prevent growth overfishing and a 533-mm or longer minimum length limit would prevent recruitment overfishing. K E Y W O R D S : growth overfishing, partial-year minimum length limit, recruitment overfishing.
The saugeye (walleye [Sander vitreus] x sauger [S. canadensis]) has been stocked across the midwestern United States to provide large-bodied percid fisheries in systems that are unsuitable for walleye or sauger. Although the saugeye often exhibits faster growth than sauger and better stocking survival than walleye in warm, turbid reservoirs, a common justification for stocking saugeye is the belief that it is more vulnerable to angling than the walleye, particularly during summer. Direct comparisons of walleye and saugeye harvest have not been conducted, therefore, patterns of walleye and saugeye harvest were evaluated in Glen Elder Reservoir, Kansas. We tagged 1,438 walleyes and 289 saugeyes with Carlin dangler tags during [2001][2002][2003]. The percentage of tags returned was nearly identical between taxa; 44.6% of the tagged walleyes and 46.0% of the tagged saugeyes were harvested. Similarly, 8 1
Gizzard Shad Dorosoma cepedianum are commonly manipulated as a prey species in the United States but are widely viewed as undesirable in small impoundments because of direct and indirect effects on desirable sport fishes. Montgomery State Fishing Lake in southeastern Kansas became populated with Gizzard Shad during a flood event in 2007, and subsequent monitoring efforts indicated the Bluegill Lepomis macrochirus population was negatively affected. Remedial action involving reservoir dewatering and application of rotenone (target concentration of 7.5 μg/L) was conducted during the winter of 2013-2014, and responses of Bluegills and Largemouth Bass Micropterus salmoides were monitored for 3 years posttreatment. Gizzard Shad were not extirpated following treatment, but their relative abundance decreased 99.8%. Relative abundance of age-0 Bluegills and Largemouth Bass immediately increased following treatment in 2014 but decreased to pretreatment levels in 2015 and 2016. Conversely, growth of age-0 Bluegills decreased in 2014, but increased to pretreatment levels in 2015 and 2016. Growth of age-0 Largemouth Bass slightly decreased following treatment. Growth between the development of the second and third annulus did not differ among years for either species. Body condition of stock-length Bluegills and stock-length Largemouth Bass was greatest in 2012 but declined in subsequent years. These results suggest that, contrary to previously published studies, the reduction of Gizzard Shad had minimal effect on Bluegill and Largemouth Bass populations in Montgomery State Fishing Lake. However, intraspecific, density-dependent functions might have masked true responses of Bluegill and Largemouth Bass growth and body condition to Gizzard Shad reduction. Managers should understand that Gizzard Shad removal or reduction can have variable effects in aquatic systems and should be cognizant of potential outcomes and how those might affect fish populations and associated fisheries.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.