Economic and other benefits of enforcing size limits in Melanesian sea cucumber fisheries

Melanesian countries have made recent progress in developing sea cucumber fishery management systems including tools such as species-specific minimum legal size limits. Despite a consensus among the scientific community that size limits are a vital management tool, decision-makers, fishers and traders might not fully appreciate the benefits of minimum size limits. Consequently, compliance and enforcement is often weak. It is relatively clear that any increase in the length of time sea cucumbers are allowed to grow increases the chances of reproductive success and prolongs their beneficial impacts on the ecosystem; however, the economic benefits of doing so are not so straightforward. This study modelled the economic benefits of imposing and strictly enforcing science-based minimum size limits in sea cucumber fisheries. Four high-value species Thelenota ananas, Holothuria scabra, H. fuscogilva, H. whitmaei were investigated, using size limits that have been recently agreed upon by the Melanesian Spearhead Group (MSG), and size distribution samples from recent export data from Fiji and Vanuatu. Our analysis found that if minimum legal size limits were enforced, the entire long-term harvest of some species could increase by up to 97% and generate up to 144% more revenue. In other words, fishers and governments lose significant revenue by not strictly enforcing size limits. This economic loss reinforces the importance of enforcing strict science-based size limits in sea cucumber fisheries.