Mystery Surrounds Latest Eel Deaths
The Age
Friday February 3, 2006
FOR the second summer in a row scientists are baffled by mass eel deaths in Victoria.
Thousands of dead eels have been found in the Western District over the past month, having been washed up or slithered out of the water before perishing.While numbers are hard to estimate, both Lake Modewarre - the site of about 30,000 eel deaths last year - and Lake Bolac have recorded more than 1000 deaths, and the figure is growing. Dozens have beached at Lake Colac and on the Eumeralla River, west of Port Fairy.The deaths are being investigated by EPA Victoria, which has theories but concedes the cause or causes remain a mystery.EPA science manager Tony Robinson said the waterways did not appear polluted and other aquatic life had been spared. "There does appear a link to the high temperatures and drought conditions we've had," he said.The best hypothesis links the deaths to the geology of the Western District. Its basalt plains are dotted with shallow crater lakes, which become shallower during drought years. Superficial water is quickly heated to temperatures more than 20 degrees. "If you combine shallow lakes, high temperatures, high salinity and high turbidity, with the wind stirring up sediments in the shallow water, that may be something to do with the reason these eels are dying," Mr Robinson said.
© 2006 The Age