Incorporating climate changes into population dynamic modelling: an individual-based modelling approach for lobster

One of the most challenging issues in fisheries management is the evaluation of the effects of fishing in the context of a changing environment. Using the pronghorn spiny lobster (Panulirus penicillatus) fishery off the eastern coast of Taiwan as an example, we developed an individual-based model (IBM) that is capable of describing the temperature-dependent life history processes and fishery practices for the spiny lobster. We then used the model to evaluate potential impacts of increased ocean temperature on the estimation of mortality-based biological reference points for fisheries management. We demonstrate that a warming temperature would increase the yield-per-recruit and eggs-per-recruit values and consequently reduce the risk of overexploitation under the current exploitation level. However, there is likely a high risk of overexploitation in the long term if higher temperatures induce extra-high natural mortality. The evaluation of effectiveness of size regulations suggests that increasing minimum legal size is proposed as a good candidate measure to reduce the risk of overexploitation for pessimistically unfavorable environmental conditions. This study suggests that an explicit incorporation of the relationships between environmental variables and biological processes can greatly improve fisheries assessment and management.