Keith L. Hurley

Habitat Use by Middle Mississippi River Pallid Sturgeon

Abstract Little is known about the habitat preferences and needs of pallid sturgeon Scaphirhynchus albus, which was federally listed as endangered in 1990. To learn more about habitat use and selection by pallid sturgeon, sonic transmitters were surgically implanted in 27 individuals from the middle Mississippi River. Study fish were located 184 times (1–23 times/individual) from November 1995 to December 1999. Of the seven macrohabitats identified, pallid sturgeon were found most often in main-channel habitats (39% of all relocations) and main-channel border habitats (26%); the between-wing-dam habitats were used less often (14%). Strausss linear selectivity index (Li ) values indicated that study fish exhibited positive selection for the main-channel border, downstream island tips, between-wing-dam, and wing-dam-tip habitats; they showed negative selection for main-channel, downstream of wing dams, and upstream of wing dam habitats. Comparison of Li values for four temperature ranges and three daily me...

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 years 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 ...

Evaluation of a 254-mm Minimum Length Limit for Crappies in Two Southeast Nebraska Reservoirs

Abstract Wehrspann and Zorinsky reservoirs are located near the largest population center of Nebraska, which has contributed to high fishing pressure and overharvesting of resident populations of black crappie Pomoxis nigromaculatus and white crappie P. annularis. To protect these popular fisheries and increase angler catch rates, a 254-mm minimum length limit was established on both reservoirs in 1994. Fall trap-net catch rates of black crappies increased 535% in Wehrspann Reservoir (1994–1998) and 721% in Zorinsky Reservoir (1993–1998). Angler catch rates from 1994 to 1998 increased from 0.26 to 2.55 crappies/h in Wehrspann Reservoir and from 0.13 to 0.82 crappies/h in Zorinsky Reservoir. Harvest rates declined below 0.03 crappies/h in both reservoirs. Growth rates declined, age structure increased, and annual mortality remained high in both reservoirs after the limit was implemented. The length limit was successful at protecting the populations and increasing angler catch rates; however, a shift in siz...

Relative Growth of White Crappie and Black Crappie in the United States

ABSTRACT We developed standardized growth models for white crappie (Pomoxis annularis) and black crappie (P. nigromaculatus) populations across the United States from von Bertalanffy growth models utilizing previously published backcalculated length at age data taken from scales. We also developed percentile distributions from backcalculated lengths which indicated results similar to the von Bertalanffy growth models.

Synchrony — An emergent property of recreational fisheries

1Nebraska Cooperative Fish and Wildlife Research Unit, School of Natural Resources, University of Nebraska, Lincoln, Nebraska 2School of Natural Resources, University of Nebraska, Lincoln, Nebraska 3Nebraska Game and Parks Commission, Lincoln, Nebraska 4U.S. Geological Survey—Nebraska Cooperative Fish and Wildlife Research Unit, and School of Natural Resources, University of Nebraska, Lincoln, Nebraska