Seafood CRC: Spatial management of southern rock lobster fisheries to improve yield, value and sustainability
University of Tasmania (UTAS)
Quota management of rock lobster fisheries in southern States combined with higher prices for shallow-water lobsters has driven effort inshore. This is because fishers now manage their business to optimise the value of each kg, not maximise catch. Deeper water lobsters are often uneconomical to fish under current management as beach price can be as little as $4/kg above lease price (as lease price responds to beach price of shallow water product). This has produced an unusual situation in fisheries management where fishers are shifting effort away from high catch rate areas and into more depleted areas. There is now a management need for improved ability to follow trends in stocks at different depths and to evaluate novel harvest strategies suited to these spatial issues. Adjusting harvest strategies to take account of spatial patterns in the biology of lobsters and patterns in the fleet has the potential to substantially increase yield, value and sustainability of the fishery. For example, preliminary modelling of the Tasmanian fishery has shown that regional size limits could double egg production in northern regions where levels are currently of concern, while simultaneously increasing yield by around 25%. Shifting effort into deeper water by means such as specific deep-water quota would be expected to increase yield given that these stocks are currently under-exploited. Translocating lobsters from slow to high growth areas leads to increased productivity and also higher beach price per lobster due to improved colour. Bio-economic modelling has indicated that gains in nett economic yield could be more than doubled in many cases through translocation (FRDC 2005/217). These opportunities also exist to varying degrees in SA and Victoria.
0. To conduct field experiments and sampling to provide additional data required for alternative harvest strategy evaluation (fisher catch sampling, translocation release survival, release movement, translocation growth transition, effects of translocation on maturity and egg production parameters, density dependent growth).
1. To develop functional management and monitoring recommendations to apply outcomes.
2. To evaluate alternative spatial management options (deep-water quota, translocation, size limits) by economic analysis.
3. To conduct field experiments on translocation to provide additional data required for economic evaluation (change in colour, tail width, condition, and ability to survive transport).
4. To determine the extent of ecological community change in deep water reef habitats in response to increased harvest rates of lobsters.
5. To evaluate alternative spatial management options (deep-water quota, translocation, size limits) in respect to yield and egg production (biological projection).
6. To enable assessment reporting of trends in biomass and egg production by depth (model fitting).