“We found a huge gradient, an enormous contrast. In reserves off Spain and Italy, we found the largest fish biomass in the Mediterranean,” said National Geographic Explorer-in-Residence Enric Sala, the paper’s lead author. “Unfortunately, around Turkey and Greece, the waters were bare.”
According to the National Geographic statement, the researchers made hundreds of dives over three years off Morocco, Spain, Italy, Greece and Turkey, setting up transects to count fish and take samples of plants and animals living on the seafloor in 14 marine protected areas and 18 open-access sites. “The result is information on the Mediterranean at an unprecedented scale,” National Geographic said.
“While the level of protection was the most important factor in determining the biomass of fish, the health of the algal forests that support the fish depended on other factors, the authors write. Recovery of formerly abundant algal forests takes longer than recovery of fish. ‘It’s like protecting a piece of land where the birds come back faster than the old trees,’” Sala said.
The study provides the first baseline that allows evaluation of the health of any Mediterranean site at the ecosystem level — not only its fish but the entire ecological community, National Geographic said. “The trajectory of degradation and recovery found by the authors allows for evaluation of the efficacy of conservation at the ecosystem level for the first time.”
Sala believes the results about fully protected marine reserves give reason for hope in waters well beyond the Mediterranean. “If marine reserves have worked so well in the Mediterranean, they can work anywhere,” he said.
Often called the “cradle of civilization,” the Mediterranean is home to nearly 130 million people living on its shores, and its resources support countless millions more, National Geographic added. “A variety of pressures keep the organisms that live in the sea in a permanent state of stress.”