Looking for fish in distress

Tthe Environment Agency is urging anglers, and anyone else planning to spend a quiet few hours by a river or lake over the coming Bank holiday weekend, to keep their eyes peeled for signs of fish in distress.

Weather patterns during the spring and summer months can create the kind of conditions which can, for a number of reasons lead to fish mortalities sometimes on a large scale. Algal blooms starving the water of oxygen, summer storms washing pollutants off land into rivers, and pollution from slurry and silage liquor are some of the more common causes of fish mortalities during this period.

With a number of large scale fish kill incidents having occurred already this summer the Agency is urging people to be alert to the tell tale signs which can give an early warning of such an event. Environment Agency, Head of Fisheries, Dave Clarke commented: "The Environment Agency has an important role in protecting fisheries, but factors which cause large scale fish deaths are often difficult to predict. As waters heat up during periods of hot weather, they becomes less able to retain vital levels of dissolved oxygen particularly in shallow or slow flowing watercourses, and where there is heavy weed growth or little or no tree cover to provide shade. Waters then become more vulnerable and prone to fish kills. Observant members of the public can play a major role in minimising the impact of fish kill incidents, by alerting the Environment Agency when they spot signs of problems."

These include:
+ usually clear lakes changing to a green or brown colour - this is often a sign of developing algal blooms
+ dimples on the water surface particularly in the early morning on shallow lakes, which can mean fish gasping for air and may be a sign of an oxygen imbalance in the water
+ a smell of ammonia, and water which is tinged brown (by comparison to normal river water colours) this is often an indication that slurry or silage liquor has entered a watercourse
+ dead fish or any other signs of water pollution, particularly after heavy summer rains which can wash a cocktail of detritus, such as gravel, silt, debris and oil off road networks and surrounding land, and into drains and ditches, which ultimately discharge into larger waterbodies.

Anyone noticing any of the above should telephone the Environment Agency Freephone 24 hour line on: 0800 80 70 60.

Environment Agency officers have been kept busy throughout the summer months, being called to pollution incidents, involved in fish rescues and undertaking restocking programmes:
+ early in June this year members of the Environment Agency’s in-house work force discovered that around 10 km of the River Tamar had become polluted from farm waste including silage and slurry. The Environment Agency launched a major emergency operation lasting a number of days, with pumps to breath life back into the river, and hydrogen peroxide to help lift oxygen levels within the affected stretch. The Agency also used electrical currents to stun fish before retrieving them and releasing them upstream. In total the pollution incident took the lives of over 10,000 fish.
+ in July this year the Agency’s Midlands region embarked upon a massive restocking programme on the River Smite at Whatton in Nottinghamshire. The programme followed a devastating pollution incident which wiped out tens of thousands of small fish on the river earlier in the summer. 10,000 small chub which had been reared and grown at the Agency’s Calverton Fish Farm near Nottingham were released into the river along with 50 brown trout from a Derbyshire fish farm.
+ naturally occurring algae are believed to have caused the death of around 500 fish in two lakes on Merseyside, at Mellors Pool, Whiston and a lake in Royden Park, near Frankby, Wirral. Environment Agency Officers deployed aerators - machines designed to increase the amount of oxygen in both pools in order to minimise the risk posed to the thousands of fish remaining in the pools.

Dave Clarke concluded: "Although in some cases the occurrence of fish mortalities cannot be helped, they can often be limited by the swift, efficient action of the Environment Agency. The Agency however does not have eyes everywhere, and often relies upon the invaluable information it receives from other river users, alerting the Environment Agency to the first signs of trouble. "