Protecting Vulnerable Stocks in Multi-Species Prawn Fisheries

J. W. Penn, R. A. Watson, N. Caputi, N. Hall, (1997). 122-129.   paper published in proceedings of the Developing and sustaining world fisheries resources: the state of science and management. Proceedings of 2nd World Fisheries Congress., Brisbane Australia, Aug 1996

Information from the unusual collapse and rebuilding of individual penaeid stocks within the Western Australian multi-species trawl fisheries assists in developing population models for penaeids and identities potentially vulnerable prawn stocks. The Exmouth Gulf stock of Penaeus merguiensisi collapsed in the 1960s and has not recovered. The P. esculentus stocks in Shark Bay and Exmouth Gulf suffered recruitment overfishing during the early 1980s, but significant reductions in the fishing effort directed at this species have resulted in increased breeding stock and improved catches, spawning stock-recruitment relationships have been developed for the two P. esculentus stocks. No such relationship is clear for the Penaeus latisulcatus stock in Shark Bay, but the data suggest that recruitment may be influenced by an environmental effect at the time of recruitment. The ability of a fishery to exert high levels of pre-spawning fishing mortality is a common factor in penaeid fisheries showing recruitment overfishing. Local geography, the position of the fishery within a species range, the presence of other species in a fishery, and the catchability, appear to affect susceptibility to overfishing.