The Comeback Cove

Great news for conservation is always exciting, so when I read about a remarkable wildlife rebound in this month's issue of PLoS ONE, I couldn't resist sharing it here. Apparently there really are more fish in the sea — at least in the Gulf of California at Cabo Pulmo National Marine Park, a 44-square-mile (71-square-kilometer) protected area off the Baja California coast.

Once called the "aquarium of the world" by renowned seafarer Jacques Cousteau, the Gulf of California boasts exceptional biodiversity, yet experiences the same overfishing pressures that threaten marine ecosystems everywhere. In 1995, residents of Cabo Pulmo responded to this vulnerability by creating a park in the gulf and establishing a community-enforced ban on fishing there. Oceanographers interested in the recovery then surveyed the reserve's population in 1999 and 2009 to gauge the change in fauna biomass, finding out in the process precisely the difference a decade can make.¹

On their first survey, large fish and top predators were nearly absent, including dog snappers, groupers, trevally, and manta rays, but ten years later those species had returned, along with marlin, tuna, sharks and five of the world's seven endangered species of sea turtle. According to marine ecologist Enric Sala, "We saw more sharks in one dive at Cabo Pulmo than in 10 years of diving throughout the Gulf of California! "² Indeed, at an average density of 4 tonnes per hectare, the amount of fish in Cabo Pulmo had increased around 463% since 1999, with the biomass of top predators increasing more than tenfold.³

The presence of these apex predators is an especially thrilling sign of recovery, as large carnivorous fish like sharks and tuna are considered bioindicators of a robust ecosystem that can support animals at high trophic levels.⁴ This boom also applies to those at the very top of the food chain, humans, in that research has shown that protected marine zones work to replenish neighboring fisheries as well.⁵ As researcher Sala expressed the relationship, marine parks like Cabo Pulmo are "win-win — we can have our fish and eat them too."⁶

Knowing that overfishing can lead to species extinction, I hope the rebound at Cabo Pulmo helps foster optimism for the successful coexistence of regulated fisheries and no-take parks. If this video from the team at Scripps Institute of Oceanography is any indication, in Cabo Pulmo this model of sustainability is going swimmingly.

Credits: Image of Cabo Pulmo mackerel is from Flickr and was taken by Octavio Aburto-Oropeza of Scripps Institute of Oceanography at UC-San Diego, which also produced the video.

1. Aburto-Oropeza, O., Erisman, B., Galland, G., Mascareñas-Osorio, I., Sala, E., & Ezcurra, E. (2011). Large recovery of fish biomass in a no-take marine reserve. PLoS ONE, 6 DOI: 10.1371/journal.pone.0023601 ResearchBlogging.com

2. Sala, E. "An Ocean Miracle in the Gulf of California - Can We Have More of This Please?" National Geographic Newswatch. August 12, 2011.

3. Jones, N. "Little Mexican Reserve Boasts Big Recovery." Nature News. August 12, 2011.

4. Sergio, F., Newton, I., Marchesi, L., & Pedrini, P. (2006). Ecologically justified charisma: Preservation of top predators delivers biodiversity conservation. Journal of Applied Ecology, 43, 1049-1055 DOI: 10.1111/j.1365-2664.2006.01218.x ResearchBlogging.com

5. Roberts, C.M., Bohnsack, J.A., Gell, F., Hawkins, J.P., & Goodridge, R. (2001). Effects of marine reserves on adjacent fisheries. Science, 294, 1920-1923 DOI: 10.1126/science.294.5548.1920 ResearchBlogging.com

6. Dell'Amore, C. "Pictures: Best Marine Park? Booming Fish Leap and Swarm." National Geographic Daily News. August 15, 2011.