Warning to dog walkers and swimmers as harmful green algae builds up at Denton Reservoir

Concerns for fish and wildlife at Denton Reservoir have been raised in recent weeks after fish have been found dead in the water.

A thick algae has appeared, which is said to be caused by high temperatures and stops the water from moving.

The area is popular with dog walkers and warning signs have been put up to to advise owners to keep pets out of the water as the algae can be harmful to pets as well as humans.

A spokesman for the Canal and River Trust said: “There is currently blue green algae at Denton Reservoir, which is not uncommon in static bodies of water as temperatures rise. The algae can be harmful to people and animals so we’ve had signs up on site since early spring advising people to keep their dogs out of the water.

“One of the effects of rapid algal growth is that oxygen levels in the water can get very low in localised parts of the waterbody.

“We hadn’t previously received any reports of dead fish but we’ll investigate and keep a close eye on things.”

The reservoir has attracted groups of people who have gone swimming to cool off . This has prompted complaints from local people that social distancing is not being adhered to by visitors.

The trust has also received a number of reports of low water levels in Grantham Canal, making it muddy.

A spokesperson said: “In many ways it’s not surprising as the spring was particularly dry.”

Its ecologists had recorded no immediate threats to wildlife but are monitoring oxygen levels and will respond to signs of distress.

“It’s important to remember that wildlife is very resilient and, if necessary, many species will simply move to the next stretch of canal which has water,” they added.

“Some species of waterfowl can actually benefit from fluctuating water levels as it makes it easier for them to find food in the exposed mud.”