Dolphins Guide Fishers in Laguna During Mullet Season

Researchers documented Lahille's bottlenose dolphins in Laguna, Brazil, guiding local fishers to mullet during the May–July migration; a decline in mullet numbers now threatens this long-standing cooperation.

For more than 140 years, fishers in Laguna, Brazil, have worked alongside Lahille's bottlenose dolphins during the summer mullet migration. The dolphins herd mullet toward shallow canals and signal fishers when to cast nets. A recent study used drones and underwater imaging to observe these interactions in detail. Declining mullet numbers are reported to threaten the fishery and the cooperative practice. Observed details: - The study observed 65 dolphins and identified over 40 individuals that collaborated with fishers. - Researchers reported that 86% of the mullet caught by fishers came from collaborative hunts with dolphins. - Fishers were nearly four times as successful when dolphins were present and were much more likely to catch fish at all. - Dolphins that participated with fishers were reported to have about a 13% higher survival rate than nonparticipating individuals. - Lahille's bottlenose dolphins are estimated at roughly 400–600 individuals, are classified as endangered, and face threats such as climate change, pollution, and bycatch. Summary: The reported decline in mullet threatens both the livelihoods of Laguna fishers and the continuity of a rare human–wildlife cooperation that has lasted generations. The future status of this cultural and ecological partnership is undetermined at this time.