Michigan Department of Natural Resources
Fisheries Research Report No.1834, 1975
Fishing Regulations for Smallmouth Bass in Michigan
W. C. Latta
Abstract.-Fishing regulations for smallmouth bass in Michigan were analyzed in Ricker's yield equation and with a review of previous fishing experiments from within the state and nationwide. Average rates for Michigan of growth, mortality, exploitation and reproduction were used in the equation. The size of greatest biomass for the growth and mortality rates postulated is about 11 inches. Under the presumed present rate of exploitation of 25%, the greatest harvest in weight occurs at an 8-inch minimum size limit. An increase in the rate of exploitation to 45% results in a maximum harvest at about 11 inches. Female smallmouth bass do not reach maturity until they are about 12. 5 inches long. A 12-inch size limit insures at least equal replacement of the fingerlings needed to maintain the existing smallmouth population with an increase in exploitation to 45%. The total number of bass harvested under a 12-inch, as compared to a 10-inch, size limit will decrease by 40%, but the number of bass harvested larger than 12 inches will increase by 46%. The number of bass 10 inches or larger, which are available to be caught but not necessarily to be kept, will increase 19%. The creel limit is ineffective as a regulation to restrict the catch or insure a more even distribution among anglers. In Lake Michigan, less than 10% of anglers catch a limit of five bass, and the creel limit would have to be reduced to one bass to realize a 50% decrease in catch. Likewise the open season for smallmouth has not resulted in an increased harvest. At present a 12-inch minimum size limit, combined with the existing 5-fish creel limit and a fishing season which is open from the Saturday immediately preceding Memorial Day to December 31, seem to be appropriate fishing regulations.