Aspects of the population dynamics of the western rock lobster, Panulirus cygnus George. II. Seasonal changes in the catchability coefficient

Abstract

The catchability coefficient, q, of a population of the western rock lobster P. cygnus was calculated monthly from November 1969 to January 1973 using measurements of catch, effort, population density, and area of reef. The catchability coefficient varied significantly during this time and was positively correlated with water temperature and water salinity, and negatively correlated with the percentage of rock lobsters in a premoult condition. A linear combination of these three factors was highly correlated with the catchability coefficient (P < 0.001) and appears to offer a method of adjusting the catchability coefficient and so leading to an improved stock assessment for this species.