LONDON, Aug. 23 (UPI) -- British fishermen are calling for a reduction in the number of swans, who are altering the ecology by eating too many weeds.
While designated as a protected species in Britain, fishermen claim the birds are eating too much of their favorite food -- a river weed called water crowfoot, or Ranunculus.
With fewer weeds, the anglers claim there is less protective cover for species such as brown trout and less habitat for breeding grounds for flies and other invertebrates that the fish rely on for food.
Conservation agencies also recognize the impact of the swans on the vital river weed is serious and experts at the Department for Environment, Food and Rural Affairs, English Nature and the Environment Agency are studying the problem, The Times of London reported.
Mike Trowbridge has been river-keeper at the Earl of Radnor's Longford Estate along the Avon near Salisbury for 24 years, and says steps must be taken.
"With the river stripped of weed the water level has dropped from 3 feet to 18 inches," he said. "It is easier for cormorants to get at the fish and it is also affecting the fly life and the reproduction cycle of flies."
