Developing techniques for enhancing prawn fisheries, with a focus on brown tiger prawns (Penaeus esculentus) in Exmouth Gulf. Final Report to FRDC for project FRDC 1999/222.
Loneragan, N.R., Kenyon, R.A., Crocos, P.J., Ward, R.D., Lehnert, S., Haywood, M.D.E., Arnold, S., Barnard, R., Burford, M., Caputi, N., Kangas, M., Manson, F., McCulloch, R., Penn, J.W., Sellars, M., Grewe, P., Ye, Y., Harch, B., Bravington, M., Toscas, P. and Meadows, J. (2003) Developing techniques for enhancing prawn fisheries, with a focus on brown tiger prawns (Penaeus esculentus) in Exmouth Gulf. Final Report to FRDC for project FRDC 1999/222. CSIRO, Cleveland.
This project has been successful in developing new approaches for the production of juvenile prawns at high densities (> 2,000 prawns.m-3) at both experimental and semi-commercial scales in Exmouth Gulf. This new production technology could lead to a 3 phase approach to the production of prawns: hatchery, nursery and grow-out. Surveys of benthic habitats and juvenile prawns and their predators, combined with information from fishery independent surveys, identified seagrass beds in the southern and south-eastern Exmouth Gulf as the best potential release sites for juvenile prawns. These surveys also found that the extensive loss of seagrass following Cyclone Vance is likely to have led to very low catches in the tiger prawn fishery and future work will investigate estimating the extent of the seagrass nursery habitat for inclusion as an environmental variable in evaluating stock recruitment relationships. Eight reliable microsatellite markers have now been developed for P. esculentus and tested to determine their effectiveness for identifying released (“domesticated”) from wild prawns using new statistical methods. Results showed that these eight loci alone would not enable reliable discrimination between released and wild prawns unless the identity of the released-stock’s fathers could be determined. This could be achieved in a cost-effective manner if the fathers’ genotypes could be deduced by genotyping a single mixed batch of larvae from each spawning, given the maternal genotypes. The results from the bio-economic model show that enhancement is only “profitable” about 50% of the time (excluding capital costs and depreciation), but highlighted that little is known of the values for density-dependent mortality and mortality due to harvest, transport and immediately after release.
|Murdoch Affiliation:||Centre for Fish and Fisheries Research|
|Copyright:||© Fisheries Research and Development Corporation and CSIRO Marine Research, 2003.|
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