Evaluating the environmental drivers of mud crab (Scylla serrata) catches in Australia

Abstract

Mud crabs are a highly valuable commodity harvested in four Australian jurisdictions. The fisheries they support are small to medium scale and prone to variation in catch rates. The degree of variation in catch rate can exceed a factor of eight in Northern Australia and is thought to be driven by climate parameters. Such fluctuations may increase in regularity and/or magnitude in future due to climate change and its associated impacts. This work documents the links between environmental drivers (particularly temperature and rainfall) and mud crab catches in representative areas throughout Australia. A conceptual model was developed to improve our understanding of the relationship between mud crab catches and environmental drivers. Time lags related to the mud crab’s life cycle were described and predictive models for domestic mud crab fisheries developed. Regional differences between river systems have been identified and rivers of similar catch and environmental characteristics grouped. The information presented here enables the prediction of 30-50% of annual mud crab catches. The findings can assist fishery managers in developing regional management plans for mud crabs and apply protective measures to the resource when necessary. The mud crab industry, and in particular mud crab fishers, can use the information herein to predict and then adjust catches to influence the market price of mud crabs and reduce their operational costs.