Eliza Barclay, National Geographic News 21 Jul 08;
The loss of Mexico's coastal mangrove forests to development is threatening the country's multimillion-dollar fishing industry, according to a new study.
Around Mexico's Gulf of California—between Baja Peninsula and the west coast of the mainland—mangroves are being destroyed to make way for high-end tourism resorts, marinas, and controversial industrial shrimp farms.
The government has overvalued such development and grossly undervalued the vital role mangroves play in supporting the region's U.S. $19-million-dollar fishing industry, the report said.
The Gulf of California harbors more than a hundred fish species, 30 percent of which depend on mangroves for survival.
In particular, the roots of the saltwater forests serve as sanctuaries and nurseries for commercial fish species such as snapper, snook, and mullet.
The study, led by researchers at the Scripps Institution of Oceanography at the University of California, San Diego, was published this week in the journal Proceedings of the National Academy of Sciences.
Money Trees
In the Gulf of California, 2.5 acres (1 hectare) of coastal mangrove helps produce an average of $37,500 worth of harvestable fish and crab species annually, the study said.
Over the productive life of a mangrove forest, more than 30 years, 1 hectare is worth $600,000.
When considering the ecological cost of development, the Mexican National Forest Commission requires developers to pay $1,020 per hectare. Over the course of ten years, this would be 300 times less than what that hectare is actually worth to fisheries, researchers say.
The research is one of the first quantitative analyses of the economic benefits of mangroves to fisheries.
"We can plant mangrove seedlings but we can't bring back all the biodiversity and complexities, and seldom can we bring back all the ecosystem services that they provide," said Enric Sala, a study co-author and marine ecologist formerly at Scripps and now a National Geographic Emerging Explorer. (National Geographic News is owned by the National Geographic Society.)
Thirteen fishing regions in the gulf produced an average of 11,500 tons of mangrove-derived fish and blue crab a year between 2001 and 2005, generating nearly $19 million for local fishers, the study found.
Worldwide, mangrove benefits have been estimated at $1.68 billion.
"Up to now, mangroves have only been recognized for their aesthetic value for high-end tourism and development," said Miguel Àngel Vargas of Pronatura Noroeste, the regional arm of the Mexican conservation organization Pronatura.
"Now we know they form the base of the region's fishing industry as well," Vargas said.
Acre for Acre
The country's mangroves, which currently encompass 2.2 million acres (886,760 hectares), are being lost to development at a rate of 25,000 acres (10,000 hectares) annually, according to the environmental group Greenpeace Mexico.
In an attempt to slow the destruction, Mexican President Felipe Calderón approved changes to the national General Wildlife Law in February 2007 that prohibit the "removal, refilling, transplant, pruning, or any project or activity that affects the integrity of the hydrologic flow of the mangrove, of the ecosystem and its zone of influence."
Conservationists applauded the change. But the country's powerful tourism industry—which has billions of dollars invested in future resorts sited on or near mangroves—is taking legal action in hopes of being granted exemptions from the law, according to news reports.
The Scripps study has broad implications for coastal conservation policy in Mexico, according to the paper's authors, who say it will give communities new ammunition to defend their fishing grounds from development.
"So far the fishery sector has not spoken out about the value of the mangroves," said Octavio Aburto-Oropeza, the study's lead author and a marine biologist at the Scripps Center for Marine Biodiversity and Conservation in San Diego.
"It's very important that they come to the discussion table to start saying how important mangroves are for food production and economic benefits for families," Aburto-Oropeza said.
The authors suggest that if mangroves are to be converted for development, then fishers dependent on the resources should be paid.
Mexico's National Fisheries and Aquaculture Commission (CONAPESCA) does not offer compensation to communities that lose fishing resources when mangroves are razed.
Ral Villaseor is deputy director of regulations for CONAPESCA.
"CONAPESCA recognizes the environmental services of the mangroves, but it is not able to compensate coastal communities for their protection," he said, "given that the mangrove is not itself a fishing resource."
