Comparison of random and nonrandom bag seine station selection methods

One random and two nonrandom but potentially more cost effective station selection methods were used to collect bag seine samples in seven Texas bay systems during October 1980-March 1981. Three-way analyses of variance were used to compare mean catch rates of five juvenile fishes among station selection methods, month and bay systems. Station selection method significantly affected the catch rates of Atlantic croaker (Micropogonias undulatus), southern flounder (Paralichthys lethostigma) and striped mullet (Mugil cephalus) but not those of red drum (Sciaenops ocellatus) and spotted seatrout (Cynoscion nebulosus). Significant differences were found among months and among bay systems for all species tested. Highly variable catch rates caused by changes in gear efficiency and patchy distribution of captured organisms may have obscured the ability to detect meaningful differences among the selection methods. Successful monitoring of juvenile fish should include year-round random sampling in each bay system. Utilization of nonrandom station selection methods, if economially necessary, should be done with caution and the data segregated from those collected randomly.