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Trap net samples of white crappie were collected in the spring from Rend Lake, Illinois, from 1978 through 1983. Analyses of age, growth, length-frequency, and diet reveal a dominant, slower-growing 1978 year class and two sub-populations, separated by growth rate and feeding behavior. At ages 11-VI crappie feeding on fish have back-calculated total lengths 10. 1, 27.6, 42.6, 58.9, and 63.2 mm greater than those of crappie of the same age feeding on an invertebrate diet.

Most large rivers within the range of paddlefish Polyodon spathula are fragmented by dams. However, little research has been done to determine if population characteristics (e.g., growth, mortality, density) vary among impoundments within river systems and how this may influence the risk of overfishing. Population characteristics and the potential for commercial overfishing were assessed for paddlefish in three impoundments of the Arkansas River, Arkansas (Pool 13, Ozark Lake, and Lake Dardanelle). Paddlefish (n = 751) were collected with gill nets from November 2003 to March 2005. Paddlefish from the most lentic and most heavily fished pool, Lake Dardanelle, had the lowest catch rate, grew fastest, and had the highest mean condition factor, weight, fecundity, and total annual mortality (67%). In contrast, paddlefish from the most lotic impoundment that was less intensively fished, Pool 13, had the highest catch rate, slowest growth, and the lowest mean condition, weight, fecundity, and total annual mortality (53%). The Lake Dardanelle paddlefish fishery appeared to show signs of commercial overfishing when managed with a 914-mm eye fork length minimum length limit and a 151-d season. Beverton-Holt population simulations modeled by impoundment indicated Lake Dardanelle was more sensitive to overfishing than the other pools. Although there was limited movement among pools, results of this study indicate that population characteristics vary among the three adjacent impoundments on the Arkansas River and that they should be managed as separate management units.

The ability to view the germinal vesicle following three treatment methods to clear opaque oocytes of nine species of fishes was compared. A mixture of ethanol, formalin, and glacial acetic acid (EFA) proved superior to a modified Stockard's solution and a dehydration series of ethanol followed by xylene. The EFA method worked well on oocytes of all species. The latter two methods were not as effective and required more time to clear oocytes. Oocytes of some species turned opaque soon after they were cleared by any of the methods, which limited the time period within which the germinal vesicle could be seen.