Natural England has pledged to continue to tackle illegal fishing and maintain precious habitats in Poole Harbour, following the deaths of five seahorses.

Conservationists had feared that illegal clam fisherman could be responsible for the unusual number of deaths, as a by-product of their activities.

Now the body whose task is to conserve and protect the natural environment has set out the actions it is taking.

Maritime adviser Fiona McNie said the cause of the cluster of spiny Seahorse deaths, which had occurred around Hamworthy, was unclear.

“But it is known that seahorses have been brought up by fishermen in the harbour over the last few years.

“Illegal fishing is a concern within Poole Harbour as the intensity and location of this activity is unmanaged,” she said.

Organisations including the police, Marine Management Organisation, Southern Sea Fisheries and the Environment Agency have banded together to combat them and it is hoped the Marine act may provide further measures.

The seahorse is protected under the Wildlife and Countryside Act and it is illegal to intentionally or recklessly kill, injure or disturb one.

She said a number of measures had been taken to protect sensitive habitats in the harbour, in particular the main seagrass beds, which are important for seahorses.

An awareness and code of conduct leaflet has been produced by Poole Harbour Steering Group, Poole Harbour Commissioners has placed buoys around the seagrass beds and a Southern Sea Fisheries bylaw prohibits fishing there.

“Seahorses are elusive and very difficult to survey accurately,” she said, although there is known to be a significant population in the harbour.

“Natural England will continue to work through the multi-agency approach to try and tackle the illegal fishing, and will continue to work to maintain the habitats in the harbour,” she added.