Dane A. Shuman

Food Habits of Juvenile Pallid Sturgeon and Adult Shovelnose Sturgeon in the Missouri River Downstream of Fort Randall Dam, South Dakota

ABSTRACT We examined the seasonal food habits and diet overlap of juvenile pallid sturgeon (Scaphirhynchus albus) and adult shovelnose sturgeon (S. platorynchus) in the Missouri River downstream of Fort Randall Dam, South Dakota. Seasonal trends were found for both sturgeon species as chironomids were consumed in the greatest numbers and dry weights during early summer, ephemeropterans dominated during late summer, and trichopterans were most abundant in early spring and late fall diets. However, diet overlap between juvenile pallid sturgeon and adult shovelnose sturgeon was low based on a Schoener index value of 0.53 in 2003 and 0.21 in 2004. Juvenile pallid sturgeon consumed a greater proportion of fish in 2003 and Ephemeroptera in 2004 compared to shovelnose sturgeon. Shovelnose sturgeon consumed a greater proportion of Chironomidae in both years compared to juvenile pallid sturgeon. These results illustrate that shovelnose sturgeon is not an acceptable surrogate for the endangered pallid sturgeon based on food habits.

Application of a Length-Categorization System for Pallid Sturgeon (Scaphirhynchus albus)

ABSTRACT Length-frequency data can be quantified using proportional stock density and relative stock density indices. However, standardized length categories must be available for each fish species. Thus, we developed standard length categories for calculation of stock density indices for pallid sturgeon (Scaphirhynchus albus.) Based on the longest fish (1,638 mm fork length) that we could find in sampling records or from angler catches, we propose the following length categories: stock = 33 cm (13 in); quality = 63 cm (25 in); preferred = 84 cm (33 in); memorable = 104 cm (41 in); and trophy = 127 cm (50 in). Using these length categories, we then calculated the size structure indices for pallid sturgeon populations in which recruitment had been supplemented with hatchery-produced fish.

Comparison of Green and White Mesh Trammel Nets and Gill Nets to Assess the Fish Community in a Large River

Abstract Standardized monitoring programs in great rivers need to identify and minimize the bias in the estimates of fish population characteristics to enable fishery managers to make informed decisions. We compared the effectiveness of green and white mesh in drifted trammel and anchored gill nets in capturing fish in the Missouri River from downstream of Fort Randall Dam, South Dakota, to the mouth of the river near St. Louis, Missouri. Sampling occurred from March to November 2006 and from April to May 2007. Paired green and white trammel net drifts (N = 383) caught 28 fish species from 12 families. Pairs of anchored gill nets set overnight (N = 193) caught 24 fish species from 12 families. Chi-square tests indicated that for most species there were no significant differences in occurrence between mesh colors in both the trammel and gill nets. However, occurrence was significantly higher in white mesh nets for goldeye Hiodon alosoides and blue sucker Cycleptus elongatus in trammel nets and for river ca...