Description and Evaluation of a Portable Drop-Net for Sampling Nekton Populations

An improved design of a portable drop-net is presented. The drop-net was used to sample estuarine nekton populations whose densities were later determined by the DeLury regression method. The drop-net samples provided mean density estimates that were 4-33% of the DeLury estimate for pelagic fishes, 50-100% for semi-demersal and demersal fishes, and 82-100% for macrocrustaceans (crabs and shrimp). The degree of variation between drop-net samples depended on the species, with the greatest variation seen in samples of pelagic fishes. We concluded that there were no important differences in density estimates from day-night drop-net samples.