An inquiry is underway after more than 150 fish were found dead in the Leeds-Liverpool canal.

Concerned walkers in the Wheelton area, close to the Top Lock pub, contacted Environment Agency officers after discovering dead and dying fish floating close to a lock system last Thursday, (November 10).

Up to 1,000 fish were left gasping at the surface of the canal in an area stretching to around a quarter of a mile after oxygen levels in the water dipped.

Boats were prevented from passing through the locks for around five hours as the situation was assessed.

Several officers visited the site to take water samples and retrieve the fish that had perished.

A spokesman for the Environment Agency said: "We took a number of samples and the oxygen levels were found to be very low.

"One of the reasons for such a drop in oxygen is the presence of a pollutant but so far we have not found any evidence of pollutants in the area.

"In the area concerned there are very few discharges into the canal, but we are still continuing to investigate what might have caused this.

"Letting the boats through the locks allowed new water through and oxygen levels improved and the distressed fish soon returned to normal."