Seventy‐Year Retrospective on Size‐Structure Changes in the Recreational Fisheries of Wisconsin

Abstract

To identify past successes and future opportunities for improved fisheries management in Wisconsin, we synthesized size‐structure information on 19 gamefish species from 1944 to 2012, incorporating data on more than 2 million measured individuals. Since the 1940s, mean and mean maximum sizes of five “gamefish” species (Lake Sturgeon Acipenser fulvescens, Largemouth Bass Micropterus salmoides, Smallmouth Bass M. dolomieu, Northern Pike Esox lucius, and Sauger Sander canadensis) have stayed fairly stable, and one (Muskellunge E. masquinongy) initially dropped and then rebounded—most likely as a product of increased catch‐and‐release fishing and restrictive harvest regulations. In contrast, four “panfish” species (i.e., Bluegill Lepomis macrochirus, Green L. cyanellus, Yellow Perch Perca flavescens, and Black Crappie Pomoxis nigromaculatus), which have not received the same conservation management attention, have experienced substantial and sustained erosions in size over the same period. Regulations for many species and species complexes have been cyclical over time, illustrating the challenge of consistently managing fisheries. Our long‐term retrospective analysis was effective at identifying new opportunities for improved fisheries management in Wisconsin (i.e., panfish management). We therefore encourage other big data retrospective approaches within and across regions to identify past successes and future opportunities in other fisheries management programs.

Inland Fisheries Habitat Management: Lessons Learned from Wildlife Ecology and a Proposal for Change

“…Although fishing results in death of harvested individuals and can result in catch-and-release mortality (Kerns et al 2012), fish are frequently voluntarily released by anglers and survive (Allen et al 2008;Gaeta et al 2011;Landsman et al 2011). Conversely, because catch-and-release angling has been effective at conserving and improving the density and size structure of certain fish populations, this angler behavior has been promoted as a solution on its own rather than focusing on habitats (Allen et al 2008;Gaeta et al 2011;Rypel et al 2016). Because stocking wildlife has not typically been cost-effective or successful to sustain exploited populations, habitat management has been a cornerstone of effective wildlife management.…”

Flexible Classification of Wisconsin Lakes for Improved Fisheries Conservation and Management

“…Panfish populations have historically been passively managed in Wisconsin (Beard and Kampa 1999;Rypel 2015;Rypel et al 2016). However, there is increasing interest in novel ways to manage panfish species for sustainability and yield (Lyons et al 2017b).…”

“…Standards for each of three major fisheries statistics (relative abundance, size-structure, and growth) were calculated from data archived in our statewide fisheries management database (Rypel et al 2016). To account for catch biases, we only examined data collected using pre-defined gear types used in specific seasons (Table 1).…”

“…Lake-class standards for fish sizestructure were calculated using a combination of mean and mean maximum size (Rypel 2015;Rypel et al 2016). For each lake and survey year combination, mean total length was calculated by species.…”

“…For each lake and survey year combination, mean total length was calculated by species. An analogous procedure was conducted for mean maximum size (i.e., mean of the five largest fish in a survey year) (Rypel 2015;Rypel et al 2016). Finally, a median and interquartile range of mean total length was calculated for each species across all lakes in a given class.…”