Sustainability assessment of the Torres Strait rock lobster fishery (T1.3)

Task leader: Dr Yimin Ye, CSIRO Marine Research

This task will conduct a field survey of Torres Strait rock lobster population in May/June each year throughout the Torres Strait area. The survey will collect data on abundance and sizes of individual lobster as well as information about the habitat at each site. This information will be analysed to monitor patterns in recruitment of young to the fishery, age composition, spatial distribution, and annual/seasonal variation in abundance of lobster.

This information will be used in computer-based models to estimate population parameters and to diagnose potential problems of the fishery. The results will help answer questions such as: What is the maximum sustainable production of the fishery? Is the current exploitation rate too high or too low? Is the fishery overfished? If overfished, what is the most effective measure to recover the fishery? How effective are the current management measures? By answering these questions, the fishery can be managed to provide the maximum benefit to the industry and local communities while maintaining its long-term sustainability.

Objectives

• Conduct annual relative abundance surveys of the Torres Strait lobster population;
• Analyse the annual survey data, the size-grade and catch effort data from processors, and catch statistics;
• Monitor fluctuations in recruitment and changes in age composition of the lobster population and assess stock response to recently introduced regulatory measures;
• Annually update the stock assessment model to include the newly available information and provide evaluation of the stock status and advice on management of the fishery.

Outcomes

• The recruitment estimate from the annual survey provides valuable information on the abundance of the fishery target 2+ age group in the next year. The industry members can use this information to inform their own judgment to forecast the production of the coming year.
• Assessment of the stock status and trends will help diagnose the health of the fishery and consequences of management interventions. Feed back of this information to fishery management authorities and the industry increases public awareness and consequently promotes proper actions.
• Identification of key biological indicators and resulting threshold reference points will be used in designing management policies and help prevent overfishing.
• The comprehensive assessment of the lobster stock and management policies of the fishery will benefit Environmental Assessments (SA, EAR, ESD, etc.), Regional Marine Planning, and Conservation Planning.