Using the robust design framework and relative abundance to predict the population size of pallid sturgeon Scaphirhynchus albus in the lower Missouri River.

ABSTRACT

Several population viability models were constructed to aid recovery in endangered Scaphirhynchus albus, but these models are dependent upon accurate and precise input parameters that are not provided with standard catch per unit effort (CPUE) indices. Nine years of sampling efforts, under the robust design framework, provided 1223 unique captures with an 18·3% recapture rate. The annual population estimates varied from 4·0-7·3 fish rkm-1 for wild and 8·4-18·4 fish rkm-1 for hatchery-reared S. albus. The relationship between abundance (N) and annual trot-line CPUE indices (x = 70.726y + 2·533, R2 = 0·91, P < 0·001) was used to predict an abundance of 13 616 ± 7142 s.e. S. albus in the lower Missouri River. The use of small-scale intensive sampling to develop a relationship with relative abundance indices reported here, may provide a framework for other fisheries management applications where large-scale intensive sampling is not feasible, but catch data are available.