The Eastern tuna and billfish fishery (ETBF) is currently managed through an input quota system based on individual transferable effort units (the number of hooks) and a total allowable effort level (i.e. total number of hooks) A spatial management policy based on a series of differential hook-penalties has been proposed as a flexible tool to discourage vessels operating in certain areas (e.g. those with high bycatch potential) and encourage operating in other areas (e.g. with less bycatch potential). In this study, the importance of catch rates per hook to location choice is assessed through the estimation of a nested multinomial logit model. Other variables in the model include distance to the location, prices of the main species, fuel prices and vessel characteristics. The effects of increasing hook penalties in key areas on fishing effort in those areas and elsewhere are assessed. Implications for vessel economic performance are also assessed.