Abstract

From 1980 to 1995, annual catch rates of southern rock lobster (Jasus edwardsii) in Tasmanian waters declined from 1·6 to 0·9 kg per pot lift. From March 1998, the Tasmanian government intends to base management of this fishery on output controls using individual transferable catch quotas. This has necessitated the development of a stock assessment model that can be used to evaluate the relative merits of a variety of alternative catch limits in terms of the trade-off between protecting the rock lobster resource and achieving a high yield. Each of eight regions around Tasmania is assessed separately because of spatial heterogeneity between regions in lobster growth, size at maturity and catch rates. The stock assessment model is size-structured and is fitted to catch, effort and length–frequency data as well as to estimates of exploitation rate from experimental data. A Bayesian estimation framework is employed to estimate the quantities needed for risk analysis. Egg production differs markedly among the eight regions: from as low as 6% of the unexploited equilibrium level in the northern regions, where the growth rate is fast, to more than 80% in the south-west, where the growth rate is slowest.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.