Comparison of Catch Rate, Length Distribution, and Precision of Six Gears Used to Sample Reservoir Shad Populations

Abstract

Abstract Hydroacoustics, trawling, gillnetting, electrofishing, shoreline seining, and cove rotenoning were used concurrently in August 1991 at Lake Texoma, Texas–Oklahoma, to compare sampling efficiency for gizzard shad Dorosoma cepedianum and threadfin shad D. petenense. A simple random-sampling design was used at nearshore and offshore stations in each of three 400–2,000-ha sites in the reservoir. Most gears provided similar evidence of spatial patterns of shad abundance among sites, but length distributions and sampling precision varied among methods. At offshore transects, catch-per-unit-effort (CPUE) data for hydroacoustics, trawling, and gillnetting were positively correlated (r = 0.45–0.80; P < 0.05) when data from all sites were combined. Gears differed in proportions of small (age-0) shad versus larger (age-1 and older) fish. Gears that collected mainly age-0 shad were trawls, surface-set gill nets, and seine, whereas catches of age-1 and older shad were greater with bottom-set gill nets, electr...