A rare fish captured on camera by a diver in Poole Bay has excited marine conservationists.

The extraordinary snap of the Baillon’s wrasse at its nest site is believed to show its previously unrecorded breeding display and is the winning image in a Dorset Wildlife Trust co-ordinated competition.

Taken by Matt Doggett from Southampton, it is appearing to guard its nest and is a first in the history of the annual Dorset Seasearch Underwater Photography Competition.

Dr Frances Dipper, one of the UK’s leading experts on marine fish, who judged the entries said: “This fish has been recorded occasionally from the English Channel and has been photographed in the Channel Islands and in west Ireland.”

The competition was launched to find photos that tell the most about little-known species or habitats, with winners selected from hundreds of images taken by divers in Dorset during 2011.

“Much of what we know about Dorset’s amazing marine life comes from the records and photographs Seasearch divers bring back,” said Peter Tinsley, the trust’s living seas manager.

“This information is extremely valuable when arguing for protection for fragile and vulnerable habitats and the photographs allow everyone to appreciate the variety of life which exists on Dorset’s seabed.”

Divers who would like to help record Dorset’s underwater wildlife can contact the trust on 01305 264620 or visit seasearch.org.uk.