UK: Mass die-off of fish reported in North Cowichan lake

A mass die-off of an invasive fish species in North Cowichan’s Somenos Lake is believed to have been caused by a lack of oxygen, stewards of the lake say. Thousands of dead pumpkinseed fish were found belly-up on the lake on Sunday, said Paul Gowland, president of the Somenos Marsh Wildlife Society. Gowland was out Monday morning conducting his weekly tests on the water and found very low levels of oxygen in the lake. “These pumpkinseed, they’re quite a tough fish. They’re not native to the area, but they’re very hardy, and they can actually take quite a low level of oxygen in the water and survive, but it was too low for a lot of them,” he said. He believes recent wind or a drop in temperature churned up the lake, mixing deeper layers of water that were extremely low in oxygen with upper layers, resulting in a sudden drop in oxygen for pumpkinseed fish. Somenos Lake is a shallow lake that suffers from too many nutrients flowing into it from fertilizer, septic fields and storm ...