• Source: 1 NEWS A health warning has been issued after potentially toxic algal blooms were found in a Canterbury lake near Ashburton. People jumping into a lake (file photo). Source: istock.com The Canterbury DHB issued the warning after blue-green algae was found in Lake Clearwater in the Ashburton Lakes Basin area. Testing in the lake had found high concentrations of Synechocystis, the DHB said. People are asked to avoid the lake and keep animals, particularly dogs, away from the water until the health warning is lifted. The DHB is also warning against eating fish and shellfish from the area, because it can concentrate toxins. If fish are eaten, people are asked to remove its guy and wash in clean water.