Japan’s dolphin tragedy

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Japan’s dolphin tragedy

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Mercury Contamination Found In Stranded Victorian Dolphins

ScienceDaily (June 11, 2008) — Monash University research into heavy metal contaminant levels in dolphins from Port Phillip Bay and the Gippsland Lakes has revealed high mercury levels may be a contributing factor to dolphin deaths.

Supervisory researcher Dr Ross Thompson said the mercury concentrations in 20 live and eight dolphins which died after becoming stranded, collected over the last two years, were measured by Honours student Alissa Monk. Levels in the dead dolphins averaged 3.45 milligrams of mercury per kilogram of tissue compared to 1.32 mg/kg in living dolphins.

"Mercury levels detected are sufficient to cause significant health impacts and were comparable to those found in areas of the world that are considered highly polluted, including the Mediterranean Sea," Dr Thompson said.

Mercury has been shown in previous national studies to bioaccumulate in dolphins, but this is the first study to find particularly high levels in stranded animals in coastal Victoria. Bioaccumulation is the food chain process whereby smaller fish containing mercury are eaten by larger mercury contaminated fish, which are then consumed by dolphins, who can consume up to ten kilograms of fish a day. Mercury levels found in fish were considered low (<0.5 mg/kg) and were fine for human consumption.

"Dolphins may be becoming stranded as a direct consequence of mercury contamination which damages their neurological system. They become potentially confused and disorientated, and strand themselves. Even the apparently healthy dolphins had high levels of mercury which put them at risk of future health complications," Dr Thompson said.

Dr Thompson said mercury is likely to have come from the sediments of the Bay and researchers are concerned that dredging activities may increase the dolphins' exposure.

"Sediment contains mercury, which is likely to have originated from historical gold mining sites where mercury was used in gold processing, as well as from other industrial sources. Over time, the mercury has been washed down through waterways, including the Yarra River, and come to rest on the bottom of the Bay," Dr Thompson said.

Dr Thompson said it was critical that further studies were done throughout the bay dredging process to ensure any further decline in dolphin health could be identified and managed.

The School of Biological Sciences research was supported by Coastcare, West Gippsland CMA, the Gippsland Lakes Board and the Dolphin Research Institute.

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Sources:   ScienceDaily 

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Every year, over 20,000 smaller whales, dolphins and porpoises are cruelly slaughtered in Japanese waters.

The meat is sold for human consumption, even though it is tainted with toxic industrial pollutants such as mercury, DDTs and PCBs, all known to be hazardous to human health. Those that have witnessed these hunts first hand, or watched our secretly filmed footage, will never forget the appalling brutality and suffering inflicted upon these beautiful, intelligent creatures.

Campaign Whale is the sole UK representative of the Save Japan Dolphins Coalition

The coalition is fighting to end the slaughter of dolphins and porpoises in Japan. Within our ranks is Ric O’Barry, former trainer of ‘Flipper’ the dolphin (a hugely popular sixties TV series and later Hollywood film). In reality, Flipper was not one, but five animals that all died during the run of the show – a sad reality for these intelligent animals when held in captivity.

Ric O’Barry is now working with us, determined to stop the slaughter in Taiji and other Japanese coastal villages, as well as highlight the shocking link between the dolphin hunts and the captive industry for dolphins around the world.

Adapted from materials provided by Monash University.   

Sources:   Campaign-whale.org