In La Réunion, an island in the Indian Ocean that is an overseas department and region of France, small-scale fishers often use surface longlines targeting tuna and billfish, but this sometimes leads to the accidental capture of sharks.

The EU-funded ASUR project is researching innovative methods to reduce the incidental catch of sharks by these longlines, bringing together scientists and fishermen to tag and release sharks and to test equipment designed to reduce shark mortality.

Enhancing shark survival

The project evaluates the probability of survival post-release, scrutinising the variables that contribute to higher survival rates, and testing whether new approaches and tools can decrease mortality. The results indicate that altering longline fishing procedures could significantly increase the survival rates of unintentionally caught sharks.

Researchers discovered that severing the 'branch line' as close to the hook as possible was the most beneficial in enhancing shark survival.

Increased fisher awareness

Additionally, the ASUR project has raised fisher awareness about better handling methods, which can prevent additional stress to sharks that are caught by mistake. The project's findings demonstrate that sharks have up to a 90% better chance of survival if they are freed before being brought aboard vessels, significantly reducing the impact of longline fishing.