Dwindling Parrotfish Key To Coral Reef Survival

Fight disinformation: Sign up for the free Mother Jones Daily newsletter and follow the news that matters.


Scarus_iseri.jpg

A study finds the future of the Caribbean’s failing coral reefs tied to fish with an equally uncertain future. The University of California Davis reports on a study of reefs overrun by marine algae (seaweeds) after a plague in 1983 killed virtually all the plant’s natural grazers, sea urchins. (Read more about this in MoJo’s The Fate of The Ocean.) With urchins gone, the corals’ only line of defense against algae is parrotfish—also grazers. But parrotfish are disappearing from overfishing, allowing algae to outcompete corals on the reef.

The researchers created a mathematical model of the reef, then looked at what the future holds, investigating a process known as hysteresis: whereby an effect lags behind its cause. “The idea of hysteresis is that you go over a cliff, then find the cliff has moved,” said UC Davis theoretical ecologist Alan Hastings. “Going back is harder than getting there. In this case, the loss of sea urchins sent the reef off the road, and now the only guardrail is the parrotfish. Our model showed that if we overfish parrotfish, and the reef goes off the cliff, we would need four times the fish we have now to bring the reef back.”

The authors suggest that local authorities act now to reduce parrotfish deaths, including outlawing fish traps. They also call on anyone visiting the Caribbean and sees parrotfish on a restaurant menu to voice their concern to the management.

208026039_f84d3ca11c.jpg

Well—as the pithy bumpersticker says—at least the war on the environment is going well.

Julia Whitty is Mother Jones’ environmental correspondent. You can read from her new book, The Fragile Edge, and other writings, here.

DONALD TRUMP & DEMOCRACY

Mother Jones was founded to do journalism differently. We stand for justice and democracy. We reject false equivalence. We go after stories others don’t. We’re a nonprofit newsroom, because the kind of truth-telling investigations we do doesn’t happen under corporate ownership.

And we need your support like never before, to fight back against the existential threats American democracy faces. Fundraising for nonprofit media is always a challenge, and we need all hands on deck right now. We have no cushion; we leave it all on the field.

It’s reader support that enables Mother Jones to report the facts that are too difficult, expensive, or inconvenient for other news outlets to uncover. Please help with a donation today if you can—even a few bucks will make a real difference. A monthly gift would be incredible.

payment methods

DONALD TRUMP & DEMOCRACY

Mother Jones was founded to do journalism differently. We stand for justice and democracy. We reject false equivalence. We go after stories others don’t. We’re a nonprofit newsroom, because the kind of truth-telling investigations we do doesn’t happen under corporate ownership.

And we need your support like never before, to fight back against the existential threats American democracy faces. Fundraising for nonprofit media is always a challenge, and we need all hands on deck right now. We have no cushion; we leave it all on the field.

It’s reader support that enables Mother Jones to report the facts that are too difficult, expensive, or inconvenient for other news outlets to uncover. Please help with a donation today if you can—even a few bucks will make a real difference. A monthly gift would be incredible.

payment methods

We Recommend

Latest

Sign up for our free newsletter

Subscribe to the Mother Jones Daily to have our top stories delivered directly to your inbox.

Get our award-winning magazine

Save big on a full year of investigations, ideas, and insights.

Subscribe

Support our journalism

Help Mother Jones' reporters dig deep with a tax-deductible donation.

Donate