* Editor’s note: The Enterprise is highlighting some of the young UC Davis researchers who will be presenting at this week’s Ecological Society of America’s annual conference in Sacramento.
In the crystal-blue water off the coast of North Andros, the largest of the Bahama’s 31 districts, spiny lobsters scuttle across the ocean floor and slip under a hut of corrugated sheet metal. Scattered across the ocean floor, these makeshift shelters, called condos, provide the perfect hideaway for Panulirus argus — until the fishermen arrive.
Spiny lobsters make up 95 percent of Bahamian seafood exports, and are its most valuable food export — whole islands depend on the crustacean for income.
Angee Doerr, a UC Davis Ph.D. candidate in environmental science and policy, studies the ecological and sociopolitical impacts of lobster diving in the Bahamas. She spent three years interviewing fishermen across the islands, from the poor, largely black population on North Andros, who motor out to sea in old dinghies, to the wealthy, white fishermen from Spanish Wells, who spend six weeks on the ocean in boats they call motherships.
In the 1980s, fishermen started building and deploying condos: a sheet of corrugated metal nailed to a couple of pieces of plywood, forming a shallow hut. The spiny lobsters are social creatures, and the condos allowed them to congregate in communities of up to 100. The crowds are easy to find and catch, a boon for the men who depend on them. However, the shelters have become a point of contention both ecologically and socially.
“Some fishermen think they should be private property, some fishermen think they are basically illegal artificial habitats so anyone can collect from them,” Doerr said. “So you get conflicts among the fishermen, you know, everything from verbal altercations to people destroying each others boats and cutting air hoses.”
Wealthier white Bahamians, who are primarily responsible for building and deploying the condos, feel that the condos should be private property: they put in the capital, they deserve the returns. Poorer black fishermen, who don’t have the means to build their own condos, argue that they should be a public resource: the manmade structures are drawing the lobsters away from the reefs in the waters they have fished in for decades.
“It becomes a race issue, it becomes a class issue, it becomes a power issue, it becomes an island issue,” Doerr said.
Bahamian law, for now, is definitive: anything on the sea floor can be used by any member of the public.
“Essentially, there’s no private property on public land,” said James Farlin, a UCD Ph.D. student in the department of land, air and water resources.
Last year, Farlin, who has a background in marine chemistry, joined Doerr on the islands to help figure out if the manmade condos were leeching heavy metals into the surrounding environment, one of the potential ecological implications of the shelters.
The wood used in the condos is often pressure-treated with chromated copper arsenate, an extremely common preservative that can protect against algae and fungi. The U.S., Canada, Australia and the European Union restrict its use in residential wood, though recent studies have shown little human or environmental risk for contamination on land.
Doerr suspected the metals from the treatment could be leaking into the ecosystems surrounding the condos as the wood decayed in the salty ocean. She and Farlin collected snips and slivers of turtle grass, pinecone algae and the plywood itself to test for the preservative’s metals.
“Out of 32 metals we can (test for), the three metals that correlated well were chromium, copper and arsenic,” Farlin said. “So, the exact same metals you would find in pressure-treated wood.”
Farlin and Doerr have yet to test the lobsters themselves, and the relationship between the metals and their proximity to the condos has yet to be definitively proven. But as heavy metals make it into the ecosystem, they begin to move up the food chain.
“In theory, if they’re getting into the vegetation, that means they’re going to be getting into your omnivores and herbivores,” Doerr said. “There’s a very strong possibility that they’re getting in through the mollusks, and then into the fish and into the lobster.”
All three metals can adversely affect lobster health, especially their chemoreceptors, which are vital for mating and foraging.
For now, the Bahamian government is trying to figure out a way to regulate the condos — if that’s even possible. Doerr believes current fishing practices are sustainable, but she estimates there are about a million condos stashed along the sea floor, and Spanish Wells boats put out hundreds or thousands more each year. Then, the lobsters become anyone’s game.
“We need to be more aware of what ecological impacts are happening, but we need to come up with some way to deal with the conflict that’s occurring,” Doerr said.