The challenge
Years of gillnet bans hadn't stopped illegal fishing that kept drowning the last vaquitas.
The case
In August 2022 the Mexican Navy placed 193 concrete blocks with 3-metre metal hooks across the 225 km² Zero Tolerance Area, the last stronghold of the vaquita porpoise, so that any gillnet set there would snag. Blocks followed in a neighbouring Extension Area in 2023, while the Navy and Sea Shepherd Conservation Society patrolled and removed nets. Sea Shepherd data show a greater than 90% decline in fishing boats inside the zone over the 2023, 2024 and 2025 seasons. Survey scientists reported a 67% probability that 7 to 10 different vaquitas, including calves, were seen in 2025, and no evidence of the roughly 45% yearly decline seen before. But the protected areas cover only 12% of the vaquitas' 2015 range, and 20% of 2025 sightings were outside them.
Why it worked
Making gillnetting physically impractical did what years of bans on paper could not, giving the last vaquitas a refuge. The scientists say recovery also needs more protected areas and a switch to fishing gear that doesn't entangle vaquitas across their range.
Sources
- Cárdenas-Hinojosa, G., Rojas-Bracho, L., Taylor, B. L., et al. (2025). Vaquita Research Campaign 2025: Report of the September Vaquita Survey. IUCN SSC Cetacean Specialist Group.
- Jaramillo-Legorreta, A., Bonilla-Garzón, A., Taylor, B. L., et al. (2023). Survey report for vaquita research 2023. IUCN SSC Cetacean Specialist Group.
- US Marine Mammal Commission. Vaquita (species of concern).
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