When coral bleaching events cause coral to die, many reef species are forced to relocate, but not the parrotfish. New research suggests parrotfish thrive when coral dies.

Scientists at the Australian Institute of Marine Science surveyed fish populations living near a pair of severely bleached reefs, the Great Barrier Reef in the western Pacific and the Chagos Archipelago in the Indian Ocean. They found parrotfish numbers skyrocketed when elevated water temperatures killed off large sections of the reef.

Compared to parrotfish living near reef sections that remained unbleached, parrotfish populations found among bleached coral were two to eight times bigger. But population numbers weren't the only figures to increase. Individual parrotfish living among bleached coral were 20 percent larger than those living on healthy sections of the reef.

All other surveyed species suffered diminished numbers in the wake of coral bleaching. Parrotfish thrived because coral bleaching resulted in new food resources.

Scientists shared the results of their survey this week in the journal Global Change Biology.

"When bleaching reduces coral cover on the reefs, it creates large areas of newly barren surfaces," AIMS researcher Brett Taylor said in a news release. "This immediately gets colonized by the microalgae and cyanobacteria, basically an internal and external layer of 'scunge,' which provides nutritious, abundant food for parrotfish."

But while the demise of coral reefs is a boon to parrotfish, the latest research suggests the hardy fish help reefs recover from bleaching by cleaning off the scunge. When reef health rebounds, the parrotfish numbers decline once more.

This ebb and flow helps keep ecosystems in balance and lends the reef habitat an added level of resiliency to environmental stress.

"Parrotfish are a vital link in the reef ecosystem," said Mark Meekan, AIMS researcher and study co-author. "As herbivores, their grazing shapes the structure of reefs through effects on coral growth and suppression of algae that would otherwise proliferate. Because of these important ecological roles, they have been described as 'ecosystem engineers' of reef systems."

Related Links
Water News - Science, Technology and Politics

Tweet

Thanks for being here; We need your help. The Space Media Network continues to grow but revenues have never been harder to maintain. With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords. Our news coverage takes time and effort to publish 365 days a year. If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceMediaNetwork Contributor $5 Billed Once credit card or paypal		SpaceMediaNetwork Monthly Supporter $5 Billed Monthly paypal only

Turtles and tourists share the same beach on a Tunisian island
Iles Kuriat, Tunisie (AFP) Nov 27, 2019
Between plastic chairs on a crowded Tunisian tourist beach, a sign indicates where another species shares the sand: a nest is buried below. On this paradisaical island off the coast of Monastir - a resort town south of the capital Tunis - tourists co-exist with loggerhead turtles thanks to a novel initiative. Since 2017, the Tunisian government and a local NGO have jointly run a turtle conservation programme under the noses of bathing-suited beach-goers, who are offered an environmental educat ... read more