A fish pass is to be installed at a weir to allow brown trout to pass freely along a river.

Fisheries officers will start work on the River Worth, at Keighley, to help the river overcome its industrial legacy.

The River Worth is an important tributary of the River Aire, and tributaries can provide valuable spawning and nursery grounds for the River Aire's brown trout population.

But many weirs, traditionally used to abstract water from mills, form barriers to fish and stop them from reaching suitable spawning grounds.

The weir where the pass will be constructed can be seen from the A650 and is owned by the Highways Agency.

The Environment Agency will carry out an electrofishing survey upstream and downstream of the weir on Tuesday to determine how many fish are currently there. An electric current is passed through the water, drawing fish in and allowing them to be noted, identified and released unharmed back into the river.

Some of the fish will be marked so another survey can be done next year to assess the effectiveness of the fish pass.

Pete Turner, fisheries officer for the agency, said: "We're hoping that this work will help the River Worth get back to its natural state and allow the trout to move more freely along the river. We'll be monitoring the river very closely to see just how effective the fish pass is."

The work will be carried out in partnership with the High- ways Agency and Yorkshire Water as part of its Riverlife project.