Asa had been walking his dogs when he noticed the dead fish floating on the top of the waterway. As a keen angler he knew that something was not quite right and suspected that the drain may have been polluted. He reported the incident straight away.
The Environment Agency sent a two-man team to examine the watercourse on Friday. They observed that as well as the dead fish, a number of others were gasping for air. Samples taken revealed a low-level of oxygen in the water.
The Environment Agency Fisheries Officers checked three miles of the watercourse in a small boat to check for pollutants. They also treated the water with hydrogen peroxide to raise its oxygen level.
The cause of the depleted oxygen levels is not known but in an interview with BBC Radio Humberside, Environment Agency officer Pete Turner, said that oxygen levels can be lowered by natural causes, such as warm weather, heavy rain, or by pollution.
The treatment of the watercourse is expected to continue today (Saturday 21st July 2012).
Updates – Pete Turner from the Environment Agency via Twitter:
That's it we're out of chemical so it's time to head back to the depot. Our officers will keep an eye on things and let us know how it goes.—
Pete Turner (@PeteTurnerEA) July 21, 2012