NORTH CAROLINA: In a new study published last week in the journal PeerJ, researchers with the University of North Carolina Wilmington, who surveyed the reefs off 12 Caribbean nations, found that overfishing is having a drastic effect on coral.
By removing the few natural predators of sponges, fishermen are actively increasing the threats against already diminishing coral populations.
As aggressive competitors for resources and space, sponges have been known to use smothering, snot and toxins to kill coral, literally living on what’s left of the remains.
Without many natural predators, these sponges continue to inflict significant damage on reef-building corals unless kept under control.
“If the goal is to save the corals that build Caribbean reefs, we have to protect the angelfishes and parrotfishes that eat sponges,” said Tse-Lynn Loh, co-author of the study.
While not all sponge species are consumed by predators on account of their toxic defences, parrotfish and angelfish do an efficient job of preventing them from taking over coral reefs in normal, undisturbed areas.
Researchers found that on overfished sites, coral colonies had twice the incidence of sponge infestation than those that were not fished at all.
The researchers hope that these findings may change the way ecologists and Caribbean nations address fishing policies on and near the reefs.
“Caribbean nations can now base their fishing policy decisions on the clear connection between overfishing and sponge-smothered corals. Coral conservation requires a healthy population of reef fishes,” said Dr. Joseph Pawlik, lead researcher for the study.
Coral reefs worldwide are seeing their local population sizes diminish, and Caribbean reefs are threatened by human activities and pollution, warming seawaters, disease and storms, which have already crippled the slow-growing sea creatures.
As a result, many corals have been added as protected species on the world conservation list. But the fish that call them home are not offered the same special treatment.
Although these fish may not be endangered species, it may soon be necessary to extend similar rights to them as protectors of the coral reefs, research suggests.