Rock Lobster Enhancement and Aquaculture Subprogram: the feasibility of translocating rock lobsters in Tasmania for increasing yield
University of Tasmania (UTAS)
Modelling of the Tasmanian lobster resource has indicated that loss of yield through spatial differences in growth of lobsters is greater than 25% of the TACC. Effects of fishing on egg production/recruitment and ecology also appear poorly managed spatially. Increasing catch targets high priority areas in the strategic plans of each stakeholder. The Tasmanian Government has stated their intent to pursue growth in primary industry as a key strategic area through the “State of Growth” strategy. The project squarely targets all aspects of the University of Tasmania's “EDGE agenda”, particularly through “Engagement” with the community by delivery of a substantial economic benefit. The need for this research has been identified by the commercial and recreational lobster sectors in each strategic plan for crustacean research since the first plan was produced by the CRAG in 1996, specifically under the topics of “stock enhancement” and “translocation”.
1. To determine the costs associated with translocation lobsters.
2. To model the economic outcomes of translocation based on available biological data.
3. To combine the cost and economic outcomes into a bio-economic model.
4. To model the economic viability of large scale translocation operations to achieve yield increases.
5. To identify crucial input data that impact on the economic viability of translocation.
6. To identify further data requirements from field experiments.
7. To evaluate cost recovery options for a long term operational system for translocation.
Translocation involves the shifting of undersize rock lobsters to new areas to increase productivity and/or quality of product. We modelled the translocation of rock lobsters from four original sites to four release sites with a range of growth rates.
Most model scenarios led to increases in yield at least double the status-quo. Greatest gain occurred with simulations of the translocation of females from the SW to the NW – in these cases the translocation of 1 tonne led to almost no loss of yield at the origin site but a 1.6 tonne gain at the release site.
Levels of egg production in northern regions are a management issue for the Tasmanian fishery and the model indicated that these would be improved by translocation. Modelling suggested that both yield and egg production benefits would be greatest when smaller females are translocated and when translocation is integrated with increased regional size limits in the north.
Economic modelling of scenarios that involved the movement of five tonnes of lobsters by charter indicated that it is possible to generate an additional kilogram of catch for around $2.60. This compares favourably with current lease costs of over $15/kg. Net state benefit was $160,000 per five tonne trip by a chartered vessel. The internal rate of return for these operations was around 200%, which constitutes an extremely attractive investment.
Three possible systems for funding translocation were developed and each involved an allocation of additional quota to fishers. Translocation appears to offer a feasible option for sustainably and substantially increasing yield by converting low growth, low value lobsters into more productive, higher value lobsters.
Keywords: rock lobster, Jasus edwardsii, translocation, yield increase, sustainable development, bio-economic modelling.