North American Porpoise on Brink of Extinction
Scientists have raised the alarm that little times remains before it's too late for saving a rare North American porpoise from going extinct.
As of 2007, they estimate only 150 of the extremely endangered vaquita (Phocoena sinus) remain in the world.
Vaquitas are the planet's smallest porpoise and exist only at the northern end of the Gulf of California, east of Baja California. Their population has dropped to just a quarter of what it was only a decade ago. A 1997 survey concluded that vaquitas then totalled 567 individuals.
Fishing nets that accidentally trap vaquitas have decimated the species. About 78 vaquitas died in fishing gear during 1993. Since then the number of fishing boats plying northern Gulf of California waters has probably doubled. Half of vaquita deaths come from the lucrative shrimp fishery. They're also killed in fishing gear set for sharks and fish.
Once fewer than 100 of the marine mammals remain, chances are they'll disappear altogether. At least 100 animals are needed to maintain a genetically-healthy population. At the current rate of mortality from nets, the vaquita population is predicted to drop from the 150 individuals alive now to 100 in just two years.
Captive breeding has saved some North American animals from extinction. But scientists advise that attempting captive breeding in this case will only result in killing even more vaquitas.
The solitary and elusive animals would be extremely difficult to catch safely. Experience with small species of dolphins indicates vaquitas would likely die if kept outside of their natural habitat. As well, it's expected that not many of the captive survivors would produce young.
Scientists from Mexico, the US and Canada say there's no time left for delaying action by doing more studies and monitoring. We already know that the only serious threat to ongoing vaquita survival is their high rate of entanglement in fishing nets.
Instead, vaquita experts recommend that funds be spent on establishing a total fishing moratorium within the porpoise's range and compensating fishing communities. The group of seven scientists warn in a peer-reviewed journal article that unless the fishing bycatch is completely stopped by 2009, vaquitas have little chance of avoiding extinction.
Armando Jaramillo-Legorreta, Lorenzo Rojas-Bracho, Robert L. Brownell Jr, Andrew J. Read, Randall R. Reeves, Katherine Ralls and Barbara L. Taylor. 2007. Saving the Vaquita: Immediate Action, Not More Data. Conservation Biology. 21(6): 1653-1655.