Effects of Waterbody Type and Management Actions on Bluegill Growth Rates

Abstract

Managers have conducted a number of activities to improve the growth rates of bluegill Lepomis macrochirus. However, attempts to compare the effectiveness of management actions often ignore basic differences in growth related to the type of water body in which populations reside. Bluegill age and growth data were collected from four different water body types in Nebraska between 1994 and 2001. Model analysis detected significant differences in the previous year's growth increments by water body type. When compared with other water body types, growth increments were greater in Sandhill lakes for age-2 and age-3 bluegills and mean length at capture was greater for age −6 and −7 bluegills. Several significant age × management activity interactions were detected within water body types. The application of supplemental feed and the absence of gizzard shad Dorosoma cepedianum increased bluegill growth increments in borrow and sand– gravel mining pits, while in flood control reservoirs, the presence of gizzard shad negatively impacted bluegill growth increments. Harvest regulation impacts were mixed in both of these water body types. Managers should recognize basic differences in growth patterns between water body types when determining which management actions should be implemented or when evaluating their success.