|
|
Black crappies Pomoxis nigromaculatus and white crappies P. annularis were sampled to index recruitment in seven Tennessee reservoirs (four main-stem and three tributary storage impoundments). Crappie recruitment in tributary storage impoundments appeared to be consistently higher in years of high discharge during the prespawn period (1 January-31 March). A similar relation was found in one main-stem impoundment; however, crappie recruitment in two main-stem impoundments was inversely related to discharge during the spawning period (1 April-30 May), and little recruitment variation was found in the fourth main-stem impoundment. In general, reservoir hydrology appeared to have a stronger effect on crappie recruitment...
|
We evaluated the potential effect of minimum size restrictions on crappies Pomoxis spp. in 12 large Tennessee reservoirs. A Beverton-Holt equilibrium yield model was used to predict and compare the response of these fisheries to three minimum size restrictions: 178 mm (i.e., pragmatically, no size limit), 229 mm, and the current statewide limit of 254 mm. The responses of crappie fisheries to size limits differed among reservoirs and varied with rates of conditional natural mortality (CM). Based on model results, crappie fisheries fell into one of three response categories: (1) In some reservoirs (N = 5), 254-mm and 229-mm limits would benefit the fishery in terms of yield if CM were low (30%); the associated declines...
|
Initial poststocking mortality, oxytetracycline mark persistence, and year-class contribution were evaluated for black-nosed crappies, a morphological variant of the black crappie Pomoxis nigromaculatus, stocked into Tennessee reservoirs during 1997-1999. Average initial poststocking mortality was low (x?? = 13%, N = 44). Lake temperature and the difference between lake and hauling tank water temperatures were significant in explaining variability in arcsine-transformed mortality estimates; however, the variability explained by these factors was low (R2 = 0.15). Oxytetracycline immersion was a highly effective marking tool; 97-100% of all crappies treated were marked, and 99% of the marks were visible 36-110 weeks...
|
|
