Corals use multiple tricks to adapt to hotter seas

Genes and physiological acclimation contribute equally to heat resistance.

Amanda Mascarelli

24 April 2014

The reefs of Ofu Island in American Samoa are a natural laboratory for studies of coral heat resistance.

Coral reefs face a daunting future: climate change, ocean acidification, and overfishing are projected to take a harsh toll in the coming decades. But a study published today suggests that some corals can adjust their physiology to cope with ocean warming.

A population of the table-top coral Acropora hyacinthus living in a back-reef lagoon off Ofu Island in American Samoa can acclimate to hot water temperatures — at least up to a point, researchers report today inScience1. The team teased apart the role of genetic adaptation (natural selection that occurs within a population) and physiological acclimatization (which occurs in individuals), showing that each had roughly equal roles in the corals’ heat resistance.

In the past few decades, reef-building corals have seen global declines owing to bleaching — discoloration that results when corals lose the photosynthetic algae that nourish them — caused by local warming spells.

The study suggests that “corals can buy more time to evolve the necessary adaptations by using acclimatization as a first line of response,” says Christian Voolstra, a coral reef genomicist at King Abdullah University of Science and Technology in Thuwal, Saudi Arabia, who was not involved in the research. But the degree to which the findings apply to other coral species and coral reef ecosystems still needs to be determined, he adds.

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American Samoa ends shark fin trade & shark fishing in coastal waters

Territory now has strongest shark protections in U.S.

November 2012. American Samoa, a U.S. territory in the Pacific Ocean, implemented a series of measures to protect sharks within its waters. Shark fishing is now banned in its territorial waters, and the sale, possession, and distribution of fins and other shark parts, is prohibited.

"Sharks have been an important part of our ocean, reef and cultural environments," said Gov. Togiola T.A. Tulafono. "Their disappearance would be devastating to the environment and our Samoan culture. An ocean without sharks is completely inconceivable to me. Sharks have supported the health of our ocean, our fisheries and our economy, and should remain that way for generations to come. American Samoa is committed to playing a serious role in ensuring that these wonderful animals survive for our future."

Last US Pacific Territory to ban shark fishing
Changes made this week to American Samoa's fishing regulations by the Department of Marine and Wildlife Resources support an executive order the governor signed in August. American Samoa is the final U.S. territory in the Pacific to forbid the trade of shark fins. The Northern Mariana Islands and Guam banned the practice in 2011. Hawaii also prohibited the trade of shark fins, in 2010.

"American Samoa, through these important actions, has now closed off the flow of shark fins through the U.S. Pacific islands," said Jill Hepp, director of global shark conservation for the Pew Environment Group. "Pacific island leadership is helping these animals, threatened by overfishing, to keep their place as apex predators. We are very pleased that American Samoa joins the growing chorus of Pacific island voices in support of shark conservation."

At the top of the food chain, sharks are critically important to maintaining balance for marine life. A recently released scientific study showed that only 4 to 8 percent of American Samoa's historic reef shark populations remain. Globally, up to 73 million sharks are killed each year, largely for their fins to supply the demand for shark fin soup.

"Their decline has risks for ocean health, but it's not too late for American Samoa's sharks," said Mike King, director of the Coalition of Coral Reef Lovers. "By taking action to protect the sharks of American Samoa, Samoans not only preserve their natural living resources but the linkage to the ocean that is so important to their heritage, Fa'asamoa, the Samoan way of life."

http://www.wildlifeextra.com/go/news/samoa-shark.html