Fishing Regulations for Largemouth Bass in Michigan V
W. C. Latta
Abstract.-Fishing regulations for largemouth 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. For the average rate of exploitation of 35%, the greatest harvest, in weight, occurs at a minimum size of 10 inches. However with an increase in exploitation, the greatest harvest occurs at a 12-inch minimum size. The difference in yield between 10 and 12 inches in minimum size is small, but the increase in biomass at the higher size limit is great. Although the relationship between spawning stock and progeny is not known, it seems prudent to protect the biomass of adults 12 inches and larger if exploitation is increasing. The increase in biomass with the increased size limit is unlikely to have any measurable effect on associated populations of sunfishes. In terms of numbers the increase in the minimum size to 12 inches will reduce the catch considerably. The creel limit is essentially ineffective as a regulation to limit the catch or to insure a more even distribution among anglers. A closed season in the spring has the potential for limiting the catch, as does the minimum size limit. 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.