Case Studies in Fisheries Conservation and Management: Applied Critical Thinking and Problem Solving
Case 4: Effects of Angling on a Previously Unexploited Wisconsin Fish Community
The effect of angling on fish population size structure is dependent on a myriad of factors, such as population abundance, the amount of angling effort, the size of the water body, and even differential vulnerability of different fish species. The opportunity to study unexploited populations can be extremely valuable, including situations where subsequent angler harvest is then assessed. Data sets for unexploited populations tend to be relatively rare. Information on unexploited populations can provide our profession with valuable examples of just what is possible when a population is not exploited. That way, realistic (i.e., feasible) management objectives might be set for various harvest regulations that a fishery biologist might select. In this case study, you will explore the effects of angling on a previously unexploited fish community in a small Wisconsin lake.
Mid Lake (4.7 ha) is one of a series of small lakes in Hartman Creek State Park, Wisconsin. The maximum lake depth was 1.8 m, and given the relatively clear water that allowed light penetration to the entire lake bottom, submergent vegetation growth was abundant throughout the lake. The fish community in Mid Lake included bluegills, largemouth bass, northern pike, pumpkinseeds, and yellow perch.
The lake was closed to all fishing from 1938 to 1976. On 1 May 1976, anglers were permitted to harvest any fish species, with seasons extending from early May through February. There were no length limits on harvested fish, and daily creel limits were liberal (five per day for largemouth bass, five per day for northern pike, and 50 per day for panfish). Random stratified creel surveys indicated angling effort of 230 hours/ha in 1976 and 62 hours/ha in 1979.