Variation in banana prawn catches at Weipa: a comprehensive regional study
Research in the Northern Prawn Fishery has focussed on aspects of the fishery, biology and environment of the prawns and bycatch species. Recent studies have also started to look at the broader effects of fishing in the NPF. The NPF is moving to managing the fishery in an ecosystem context i.e. with a better understanding of the factors that affect prawn and non-target species populations, other than fishing. To achieve this goal, research, management and industry need to develop broader, and more integrated approaches to understanding different factors that are likely to affect the fishery. The development of these approaches parallel the NPF’s goal of moving to an Environmental Management System. The research in this proposal will build a framework for developing an understanding of variation in banana prawn stocks in the Weipa region, in an ecosystem context, and develop more integrated approaches for research and management strategy evaluation in the NPF. It will provide a prototype approach and models for potential application to the broader NPF and other prawn fisheries in northern Australia.
The Weipa region is a high priority area as catches have been only one tenth of the long-term average catch for 4 consecutive years, even though other regions have had extremely high catches during this time. These low catches in the Weipa region can not be explained by low rainfall alone. The decline in catch from Weipa has resulted in a decline in exported banana prawns in the region from a value of about $12 million a year less than $1.2 million each year.
The research in this proposal bridges two high priority research areas identified by NORMAC in its 2003 research priorities: 1. Assessment of the status of the fishery including management strategies for the fishery; and 2. Improved knowledge of environmental factors of importance to the fishery. It also addresses a priority research area identified by the NPFAG at its May 2003 meeting.
Final report
Since about the year 2000 there have been very low catches in the Weipa Region of the Northern Prawn Fishery (NPF); these low catches were different to other areas of the NPF where they continued to fluctuate around long-term means and continued to fall within predicted levels. Industry and managers were concerned about these anomalous catch levels and debated whether or not the very low catches were a result of: overfishing; changes in the environment; changes in fishing practices; or the result of recent management changes. This project was meant to explore these possible hypotheses and advise management of a course of action.
The project was an 18 month desktop study which examined historical catch and environmental data by a variety of means. Three workshops were attended by experts from CSIRO, QDPI, universities, fishers and managers. Several approaches were simultaneously undertaken by four Working Groups. In addition there were also studies on: reproductive dynamics; fleet dynamics; trophodynamics; and fishing effort analysis. A Decision Support Framework was established for systematically examining the hypotheses, thresholds of accepting or rejecting them, and suggested management actions determined.
