Michigan Department of Natural Resources
Research and Development Report
No. 253
Fisheries Research Report No. 1783, 1971
Angling on Mill Lake after a 5-Year Period of No Fishing
James C. Schneider
Introduction.-Mill Lake, a 136-acre warmwater lake in Washtenaw County, Michigan, was closed to fishing from October 1, 1964 to August 1, 1969, for a study of fish population dynamics. This is a report on the creel census conducted the first 3 days the lake was reopening to angling, August 1-3, 1969.
As part of the study on fish population dynamics, the number of fish present in Mill Lake was estimated each spring by means of the mark-and-recapture technique (Schneider, 1971). In 1969, the population was unusually large due to a succession of strong year classes. Growth was slow, indicating that the lake was at its carrying capacity. Excellent fishing was anticipated for the special opening day, August 1; and advance publicity to the local newspapers assured a large turnout of anglers. Recognizing that there was a unique opportunity to (1) observe the impact of angling on a known fish population and, (2) to find out if angling quality would be enhanced by the 5-year closure, an intensive creel census was conducted on opening weekend, August 1-3, 1969.
The effects of fishing on lightly exploited fish populations in northern Michigan lakes have been reported by Patriarche (1960) and Clady (1970). Patriarche noted that after lakes in the Rifle River Area passed from private to public ownership (and from very light to heavy fishing pressure), the catch in the first year far exceeded that in the following years. Clady predicted a similar decline if the harvest of bass from the lakes in the Sylvania Tract was not greatly restricted. Whereas in these northern, relatively unproductive lakes, there is clear evidence that fish can be over-harvested (i.e., a drastic decline occurs in the catch and the fish population), the effect of angling on the fish populations of the southern, more productive lakes is apparently so small that it is difficult to measure. For example, any buildup in the fish population caused by closure of Mill Lake to fishing was obscured by naturally caused fluctuations in recruitment (Schneider, 1971). Bennett (1962, p. 262) cites other evidence that fish populations are not easily decimated by angling.