Targeting Economic Objectives of ITQ Lobster Fisheries When Recruitment Is Volatile

Management decisions for southern rock lobster Jasus edwardsii utilize length-based modelling of the stocks, such as for setting total allowable commercial catches (TACC).   This population modelling represents variation in productivity that occurs through fluctuations in recruitment from year to year.  A common issue for all rock lobster fisheries that use this approach is that recruitment can vary outside the ranges seen historically.  The research presented here examined the vulnerability of population model based management advice to changes in recruitment and also explored whether some strategies were more resilient to large changes in recruitment strength.  This used a 40 y time series of recruitment estimates from 1972 to 2012 from the South Australian Southern Zone and the Tasmanian fisheries.  The economic yield maximizing TACC varied with recruitment and became unstable at higher TACCs that attempted to capture high yields when recruitment was good.   It was possible to set lower TACCCs that provided high economic yield for most recruitment scenarios although this stability came at the cost of some sacrifice of yield when recruitment was unusually high.