Trends and Synchrony in Black Bass and Crappie Recruitment in Missouri Reservoirs

Largemouth Bass Micropterus salmoides , Spotted Bass M. punctulatus , White Crappie Pomoxis annularis , and Black Crappie P. nigromaculatus are popular components of many large reservoir sport fisheries, and a better understanding of these populations and their dynamics would improve our management capabilities. We used long-term datasets (13–37 years) collected from 15 Missouri reservoirs to assess temporal trends and synchrony in sport fish recruitment by using catch per unit effort of age-1 (CPUE1) black bass Micropterus spp. during spring electrofishing (N /h) and CPUE1 of crappies Pomoxis spp. during fall trap-netting (N /net-night) as our index of recruitment. Although CPUE1 exhibited high interannual variation within a reservoir, time series analysis revealed only two significant trends for each of the black bass species, with all trends indicating increasing recruitment. White Crappie CPUE1 showed abrupt declines in all four reservoirs in the Osage River basin, with these declines occurring in different years in each reservoir. White Crappie CPUE1 in one northern reservoir and Black Crappie CPUE1 in all reservoirs appeared to be increasing over time. Within a species, some regional synchrony in CPUE1 occurred for Largemouth Bass, White Crappie, and Black Crappie but not for Spotted Bass. However, synchrony within a species was not universal and in some cases did not exist even among arms within large reservoirs. With few exceptions, there was little evidence for synchronous recruitment among species; those that occurred were among congeners. The lack of synchrony among black bass and crappie recruitment suggests that management practices designed to improve recruitment of one species may not enhance the recruitment of another species. Received February 21, 2012; accepted August 9, 2012