Most marine protected areas aren’t doing their jobs to project fish and other aquatic life, according to new research from the University of Tasmania.
The study, published this week in Nature, found that 59 percent of the marine protected areas (MPAs) looked at by researchers were “not ecologically distinguishable from fished sites.” MPAs are set up to protect marine life and habitat but operate under vastly different rules and regulations from region to region — some even allow seabed mining, and most allow some level of fishing. The study looked at five markers that determine the success of an MPA: how much fishing is allowed in the MPA, how well enforced that fishing rule is, the age and size of the MPA, and whether the MPA is an isolated environment or surrounded by habitat that was desirable to aquatic life but isn’t in the protected zone.
The researchers found that a successful MPA had at least four out of five of these markers — it prohibited fishing, was well enforced, had been protected for longer than 10 years, was larger than 100 square km (about 38.6 square miles) and was isolated by deep water or sand, so that fish wouldn’t pass easily between protected and unprotected areas. The MPAs that had four out of five of the parameters had twice as many large fish species and 14 times more shark biomass per transect as regular fished areas. This increase in species richness and abundance has been documented in regions that have closed parts of their waters to fishing — when a town on Mexico’s Gulf of California banned fishing, it saw its marine biomass increase by 463 percent from 1995 to 2009.
The study’s results highlight the fact that, while the number MPAs are “increasing rapidly” around the world, these MPAs need to be better managed if they are to successfully protect marine life.
“Our results show that global conservation targets based on area alone will not optimise protection of marine biodiversity,” Graham Edgar, lead author of the report, told the Guardian. “More emphasis is needed on better MPA design, durable management and compliance to ensure that MPAs achieve their desired conservation value.”
Globally, just 2.8 percent of the oceans are protected by some sort of MPA, and less than half of this protected ocean area is closed completely to fishing. Last year, there were international talks on a proposal to create what would have been one of the world’s largest marine reserves off the coast of Antarctica, but they failed after resistance from fishing interests in Russia, Ukraine and China. The lack of MPAs and the fact that many MPAs aren’t effective puts additional strain on an ocean ecosystem that’s stretched thin from overfishing and that’s gravely threatened from the effects of ocean acidification.