The Environment Agency has welcomed the weekend’s rainfall following the growing number of reports it had received about fish and other aquatic life that have suffered during the prolonged dry weather.

Low rainfall, high temperatures and the heavy demand on water supplies dried out ponds and reduced flow levels in rivers throughout Kent, Sussex, Hampshire and the Isle of Wight.

When flow levels drop and water temperatures rise, fish and invertebrate species struggle for survival in increasingly overpopulated clusters. The increased demand for dissolved oxygen levels, as essential to the fish as the air we breathe, plummets as a result.

The hot and sunny weather has also encouraged the growth of algal blooms, which put further pressure on the oxygen levels in the water.

The algae thrive in water that is high in nutrients, such as phosphates and nitrates, which are commonly found in fertilisers, detergents and sewage. The blooms decimate oxygen levels and can cause irreversible damage to aquatic ecosystems. Some algae can also produce poisons that cause illness and rashes on contact.

The Agency’s Hampshire and Isle of Wight Area Manager, Peter Quarmby, said, “The prolonged warm spell and lack of rainfall means that some juvenile species will not survive; causing damage to both current and future fish stocks. This is particularly devastating in sites where fish populations, such as salmon and trout, are already in decline.

“The upper reaches of rivers fed by surface water, like those in the New Forest, have been particularly affected by the hot weather and low rainfall.

“Unfortunately there is no quick fix, simply pouring more water into dry ponds doesn’t work – the damage has already been done. The bed of the pond or river has hardened, destroying the habitat of the invertebrates and killing the plant-life that the fish need to live on.

“Although we have had some successful fish rescues this summer; moving them to a new location is not always possible and in any case, it can put fish under more physical stress and kill them. Re-oxygenating the water using chemicals and machinery can provide short-term relief, but unless water levels are restored, it can just postpone the problem. It is not a permanent answer.

“The only real solution is for it to rain and for time to allow natural recovery.”

Reducing the amount of water drawn from the environment can help to prevent watercourses from suffering in the warmer weather. For example, the Environment Agency has negotiated reductions in the water taken from different sites across the Region, including The Moors in Bishops Waltham, Swanbourne Lake near Arundel and the River Darent in Kent.

Mr Quarmby added, “We all have a part to play in protecting our environment – reducing the use of household products containing phosphates, understanding the need to conserve water and keeping the use of garden chemicals to a minimum are positive actions that everyone can take.”