EVALUATION OF A NEW-TYPE OF BOX SPLITTER DESIGNED FOR SUBSAMPLING ESTUARINE ICHTHYOFAUNA

We designed and tested a wooden box splitter for use in subsampling es tuarine ichthyofauna in the field. Results showed that the splitter op erator had a significant effect on the estimation of the original samp le volume whereas the splitter being used did not. Estimates of the or iginal sample volumes of water or original fish abundances were biased . Coefficients of variation ranged from 1.90% to 4.10% for the volumet ric subsamples and from 0.00% to 29.02% for fish abundance subsamples. The precision of estimates of abundance or of species composition dec reased with increased splitting. However, the species composition and length-frequency distribution of the original samples were preserved i n the subsamples for 75% or more of the first-level splits. This subsa mpling device is practical in the field and statistically adequate for use in a fisheries program.