Fish stocks and water quality on stretches of the River Test are in a poor state, warn conservationists.

Environment Agency measures on the Test between Kimbridge and Romsey rate fish numbers as “poor” and water quality in the Lower Test, between Romsey and Totton, is also rated “poor”.

A report published this week by the Royal Society for the Protection of Birds (RSPB) highlights the problem of diminishing fish numbers on the Test, a mecca for anglers and an internationally-important chalk stream habitat.

Invasive species of signal crayfish and American mink and over abstraction are partly to blame, say the RSPB.

The charity called on Environment Agency, which oversees the South-East River Basin District management plan, to take urgent action to ensure improvements are made.

Steve Gilbert, the RSPB’s conservation programme manager, said: “There are many pressures on our waterways and the life they support. We have to do all we can to protect these vital wildlife habitats and ensure people can continue enjoying them.”

Joe Stevens, principal planning officer at the Environment Agency’s river basin planning team, said: “The Lower Test between Romsey and Totton is currently at poor status, because the film of algae on the river gravels is excessive.

“This may suggest an excess of nutrients in the river water that is not being picked up by routine chemical sampling and we are investigating the likely causes of this.”

He said that levels of tributyl tin (TBT), a chemical used extensively in the past as an anti-fouling paint on ship’s bottoms, was still overpresent in sediments close of the estuary.

“We would also like to see improvements in the diversity of water plant communities in this stretch,” said Mr Stevens. “Further improvement in chemical water quality and ongoing habitat improvement work with landowners and river managers should help the river plant communities to better health here.”

It’s not all bad news, says the Environment Agency, as water quality in the stretch of the Middle Test between Stockbridge and Mottisfont is currently rated “good” .

And a recent survey of the Test at Romsey’s War Memorial Park revealed eight species of fish, including salmon parr, grayling, wild brown trout, chubb, perch and minnow. Mr Stevens said: “We are doing a lot more fish survey work this year and the early results of these extra surveys are extremely encouraging. We will continue to work with river keepers and landowners to improve habitat.

“The Catchment Sensitive Farming Project continues to work closely with many landowners in the Test Valley, who are continuing their efforts to reduce the amount of farm nutrients that are washed from their soils to the River Test and the important chalk aquifers that provide the base flow for the river and the raw drinking water that Southern Water clean and polish for domestic supply. ”

* Contractors have just completed a scheme to help prevent flooding in Romsey along the Fishlake Stream. The new drain and grill will stop debris clogging up the watercourse.