Analyses of the Sauger Fishery with Simulated Effects of a Minimum Size Limit in the Tennessee River of Alabama

Saugers Stizostedion canadense were collected in winter and early spring of 1993–1994 and 1994–1995 to describe population characteristics and exploitation rates in the tailraces of Guntersville, Wheeler, and Wilson dams along the Tennessee River in Alabama. Population modeling simulated the response of the fishery to the effectiveness of a newly imposed 356-mm (total length, TL) minimum size limit. The sauger populations in these three tailraces consisted primarily of fish age 2 and younger that were less than 400 mm long. Total annual mortality between age-1 and age-2 fish was high, based on catch rates of specific year-classes, and ranged from 64% to 83%. Age-1 and age-2 saugers averaged about 270 and 350 mm total length (TL) respectively, and from our observations, sauger anglers routinely harvested fish at age 1. Unadjusted (not corrected for tag nonreporting) exploitation rates over the 2-year period ranged from 16% to 30% at the three tailraces and averaged 24%. However, the two methods used for calculating adjusted exploitation provided nonreporting rates of 15% and 73% for reward tags. Thus, the average adjusted exploitation rate ranged from 28% to 89%. From both age and size-structure data and total and fishing mortality data, sauger exploitation was high. Population modeling indicated that a 356-mm minimum size limit with natural annual mortality rates of 25% and 40% increased yield at exploitation rates ranging from 30% to 80% when compared with no size limit. The magnitude of differences in yields increased at progressively higher levels of exploitation with a size limit. However, we predicted total numerical catch of fish would decrease with the minimum size limit. These analyses indicated that “growth over fishing” had occurred; saugers were harvested at too high a rate before reaching their full growth potential. The new size limit combined with a reduced creel limit from 15 to 10 fish/d for each angler will allow more saugers to realize their full growth potential. Finally, we found that saugers mature at about 300 mm TL, and the size limit protects these fish from harvest.