In hot water

More than 180 000 farmed salmon worth £1.3 million died this summer
because of abnormally high sea temperatures off western Scotland. The salmon
were mostly killed by sea lice, parasitic crustaceans that infest salmon farms
unless they are treated with biocides such as hydrogen peroxide. Farmers were
unable to use the chemical because it breaks down above 14 °C, and for much
of August sea temperatures remained at 17 °C. Neil Wells of the Southampton
Oceanography Centre says the high water temperatures were simply “a short-term
response” to hot weather.