Changes in Wisconsin's Lake Michigan Salmonid Sport Fishery, 1969-1985

Abstract

The modern sport fishery for salmonids in Wisconsin waters of Lake Michigan was begun during 1963-1969 with the stocking of rainbow trout Oncorhynchus mykiss, lake trout Salve/inns namaycush, brook trout 5". fontinalis, brown trout Salmo trulta, coho salmon O. kisutch, and Chinook salmon O. tshawytscha. The fishery grew rapidly during 1969-1985 as angler effort increased 10-fold, catch rate doubled, and catch increased 20-fold. The stocking and catch became increasingly dominated by Chinook salmon, with coho salmon and lake trout of secondary importance, and brown, rainbow, and brook trout of least importance. Trolling dominated the fishery, particularly by launched-boat anglers and, more recently, by moored-boat anglers. Charter boat trolling grew the most continuously and had the highest catch rates. The catch by trollers was dominated by Chinook and coho salmon and lake trout. Pier, stream, and shore anglers fished less overall, but had catch rates that were similar to launched-boat anglers. The catch by pier and shore anglers was spread among chinook and coho salmon, and lake, brown, and rainbow trout. The catch by stream anglers was dominated by chinook salmon. The percentage of stocked fish that were subsequently caught (catch ratio) was highest for fingerling chinook salmon (12.9%). Yearling brook trout, brown trout, coho salmon, lake trout, and rainbow trout had intermediate catch ratios (5.1-9.8%). Fingerling brook trout, brown trout, and lake trout had the lowest catch ratios (2.5-3.5%). The catch ratio for rainbow trout dropped from 9.8 to 5.1% after stocking with a different strain (the Shasta strain). Fingerling rainbow trout produced the lowest returns (< 0.5%). We derived stocking recommendations for each species and life stage based on these catch ratios, and catch objectives based on maintaining catch levels recorded during 1983-1985.

A Spatially Explicit Assessment of Changes in Chinook Salmon Fisheries in Lakes Michigan and Huron from 1986 to 2011

“…Fishing effort and CPE.-In U.S. waters, we used estimates of targeted fishing effort for the boat mode of angling to track changes in fishing effort. Troll fishing from boats is the most effective mode of capturing Chinook Salmon and regularly accounts for about 85% of the within-lake harvest (e.g., Hansen et al 1990;Rakoczy and Svoboda 1997;Benjamin and Bence 2003a). We assumed that boat-mode effort would be the best type of effort to characterize the spatial and temporal changes in the fishery.…”

Applications of Bioenergetics Models to Fish Ecology and Management: Where Do We Go from Here?

“…Bioenergetics model application to Lake Mich-igan began because of management concern about the predator-prey balance in this highly valuable system, and it showed that bioenergetics models are important and effective tools for investigating otherwise difficult questions. The application of bioenergetics models to Lake Michigan spurred management agencies into reviewing and modifying their management and stocking policies (Hansen 1986;Hansen et al 1990;Keller et al 1990) and to enhancing their monitoring and research programs (Brandt et al 1991). Few would argue, however, that bioenergetics model estimates were precise within ±10% of true values; rather, estimates were reasonable enough to show trends in predator consumption and directions and time scales of expected changes such that a management response was warranted.…”

A Comparison of Two Methods of Rearing and Stocking Coho Salmon in Wisconsin's Waters of Lake Michigan

“…Wisconsin's Lake Michigan creel survey, an annual survey since 1969 (Hansen et al 1990), was used to compare the return rate of each stocking strategy in the sport fishery. Most coho salmon observed by creel clerks were weighed to the nearest 0.1 lb (0.45 kg), measured (total length) to the nearest 0.1 in (2.54 mm), and examined for fin clips.…”

“…Before 1984, Wisconsin's Lake Michigan coho salmon stocking program used only yearling coho salmon stocked in the spring at 14-16 months of age and averaging 152 mm in total length (TL) and 22.7 g in weight. This stocking program produced returns to anglers of 5.9% from 1968 to 1984 (Hansen et al 1990and during 1986-1992, Wisconsin stocked accelerated-growth fingerling coho salmon in the fall (Figure 1). These fish were stocked in October or November at 9 months of age and at an average size of 127 mm and 18.2 g. The switch to accelerated-growth fall fingerlings was made to save hatchery space and reduce rearing costs.…”