A conservation expert is to investigate the effects of pollution and global warning on marine life.

Conservation groups have teamed up to employ the marine officer for an area of coastline stretching from Hampshire to the Thames estuary.

The Sussex Wildlife Trust, based in Henfield, is one of several organisations in the South East to back the appointment Trust worker Mike Russell said the new post would also be a chance to raise awareness of the problems hidden beneath the waves.

The work could pinpoint why fish usually found in warmer waters are being found off Sussex while traditional species such as monkfish, cod and herring are declining.

Recent exotic fish found in the Channel include mako and thresher sharks, sunfish and poisonous Portuguese man-of-war jellyfish.

Mr Russell said: "About 85 per cent of the population of Sussex lives within five miles of the sea and the coastline of the county extends for some 100 miles.

"Local divers have seen less and less wildlife during the last 20 years and, with similar observations from other parts of the country, it has led to calls for some action to stop this degradation."