A Niche for Nasty Nippers: Exploring Harvest Management for Control of Invasive Asian Paddle Crabs in Aotearoa New Zealand

Abstract This paper examines the feasibility of opening a fishery in New Zealand to manage the invasive Asian paddle crab Charybdis japonica. C. japonica is known for its predatory nature and high reproductive capacity, posing a threat to native species and benthic ecosystems The current management approach of surveillance and research, has been ineffective in halting the continuous spread of C. japonica around the upper North Island. We assess the feasibility of commercial exploitation by assessing fishing costs, stock availability, and consumer interest. We find strong interest by fishers in participating in a C. japonica fishery and considerable interest among consumers to purchase and consume invasive crabs even at prices above the retail prices of other species. We assess the public acceptability of commercialisation, emphasizing the importance of fishery management, safeguards and marketing in such a strategy. We examine the legal environment surrounding invasive marine species, which does not consider or enable commercial harvest as a sustained management tool. Regulatory limitations hinder the conducting of commercial fishing or consumer trials to investigate the viability of a fishery. There are inherent risks in commercialising an invasive species, however, these must be balanced against allowing the socially unacceptable current population trajectory to continue. This study contributes to the ongoing discourse on invasive marine species management and provides economic insights into the potential for a C. japonica fishery. We recommend a balanced approach that maximises ecological integrity, aligns with societal expectations and ensures sustainable resource utilization.