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March 2014    Download the Entire Issue (PDF) Available to the Public Vol. 29, No. 3   RSS Feed for Undercurrent Issues
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Flotsam & Jetsam

from the March, 2014 issue of Undercurrent   Subscribe Now

Manta Rays are Safe in Indonesia. On February 21, Indonesia announced it would become the world's largest manta ray sanctuary. The archipelago's 5.8 million square kilometers of ocean are protected from manta fishing and export. That's because government officials were persuaded by evidence that mantas are worth more alive than dead -- a study published last year in online journal PLoS One said a manta ray is worth up to $1 million during its lifetime, thanks to tourists who will pay to swim with them, but only worth up to $500 when dead. Now conservation groups are teaching fishermen about the value of manta ray tourism, and more than 200 policemen have been prepped to enforce the law.

A Common Chemical Kills Coral Reefs. Thanks to subscriber Jonathan Scott (Waltham, MA) for alerting us to research showing that a common chemical used in many soaps, shampoos and cosmetics is killing young coral reefs at concentrations commonly found in the environment. The study, in this month's issue of Ecotoxicology, found that benzophenone-2 (BP-2) is toxic to coral reefs, causing increased rates of death and bleaching. BP-2 is found in U.S. wastewater, and once in the environment, can quickly kill juvenile corals at even low concentrations. BP-2 is similar to oxybenzone, the active ingredient in many sunscreens (although it's not used in U.S. sunscreens), and it's considered an emerging contaminant of concern by the EPA.

He Can't Swim with Them, But He'll Protect Them. In last month's Flotsam, we listed an item about Leonardo DiCaprio saying he was mentally scarred after swimming too close to great whites during a cage dive in South Africa. That didn't prevent him from taking out his wallet to fund marine protection efforts. Last month, he gave a $3 million grant to the nonprofit Oceana. Spread over a three-year period, the grant will support Oceana's work to advocate for responsible fishing measures, including a ban on California drift gillnets, which often catch and kill the 'bycatch' of dolphins, turtles, whales and other marine animals.

Coroner's Warning: Dump Your Weights. Emma Carlyon, a coroner in Cornwall, England, warns all divers to dump their weights when in trouble on the surface. This is after investgating the 2010 death of experienced diver Clive Robert Jones, who become separated from his buddy during a dive on a Cornish reef and was spotted on the surface waving for help. After a minute he slipped underwater and fellow divers later found Jones, 60, lying on the sea bed and still wearing all his weights. His computer showed he ascended 100 feet in less than a minute. The safety inspector who examined the weight belt said the Velcro surrounding the weights was too strong. While she could find no evidence why Jones had surfaced so quickly, Carlyon accepted that the weight harness Jones was wearing had been difficult to remove, and wrote in a statement, "I think it would be appropriate to write to dive organizations and to the manufacturers of this belt to highlight the difficulty, as highlighted in his case, in removing the belt and the need for divers to check they are able to release the belts."

Starfish Can See. Starfish use photoreceptors, lightsensitive organs at the tips of their arms, to find their way home if they stray from the reef. But scientists didn't know whether they're actually real eyes or simply structures that detect changes in light intensity. Resarcher Anders Garm at the University of Copenhagen in Denmark solved the mystery. He collected healthy starfish and removed the arm-tip photoreceptors from a third. He made similar incisions on another third but left the eyes intact; the remaining starfish stayed untouched. He moved all starfish from their rocks onto the sandy bottom -- where they would starve if they didn't get back to the reef. Intact starfish promptly scuttled back to the rocks. Eyeless starfish scuttled just as fast, but in random directions. That shows they need the photoreceptors to recognize and move towards the reef by forming an image of it -- which means they can process visual information. Garn thinks the visual task of navigating towards large stationary objects was an important step in eye evolution, meaning even humans' eyes evolved so we could find our way home.

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