An analysis of variation in catchability of green tiger prawn, Penaeus semisulcatus, in waters off Kuwait

A method for assessing variation in catchability of single cohort fisheries based on catch and effort statistics was developed. The results of its app lication to the Kuwait shrimp, Penaeus semisulcatus, fishery showed that ca tchability declined gradually with progress of fishing in general, but ther e was a rise in December or January. The pattern of variation was associate d with possible schooling behavior at the beginning of a fishing season. In itially, catchability was high, but, as intensive fishing dispersed the sch ools, or reduced population density, catchability declined. The midwinter i ncrease in catchability was probably due to an inshore spawning migration. There were also substantial interseasonal variations in catchability becaus e schooling was associated with strong recruitment and environmental condit ions.