Fishery for the deep-water spiny lobster Palinurus delagoae in Mozambique, 1980 to 1999

Abstract

Catch and effort data collected from 1980 to 1999 from the commercial trap fishery for Palinurus delagoae off Mozambique are presented.Generalized linear models, using the variables year, month, area, and depth, indicate a marked decline in catch rate with time.Intensive exploitation has led to a rapid decline in catches (102 to 48 tonnes) and catch rates (0.74 to 0.33 kg/trap haul) during the last five years. This decline indicates that the population is sensitive to the high fishing levels (over 200000 trap hauls), particularly since 1993. As these lobsters are generally slow growing and long lived, recovery is expected to take a number of years, provided that fishing stays relatively low. Studies of different size categories show that juvenile catch rate was highest in deep water and during summer after the moult in August to October, whereas the larger adult size category was caught more in shallow water during spring, probably during the mating aggregation. These catch rates reflect an inshore migration of juveniles from deep to shallow water. The decline in catch rate appeared greater amongst the small (juvenile) and medium lobsters because these more abundant categories are more often the target of the fishery.