GLOBAL warming could be responsible for driving sea creatures which have rarely been seen in British waters to the North-East coast.

Already this week a rare 6ft swordfish has been caught off Northumberland and an unsuspecting fisherman netted a 250lb Porbeagle shark further down the coast at Sunderland.

Last week, fishermen reported four shark sightings in the North Sea off the coast at Seaham.

The latest encounters have added weight to growing evidence of global warming, with the average water temperature in the North Sea having risen by as much as a full degree during the past ten years.

And experts say we could expect to find more exotic fish off our shores.

University of Newcastle marine biologist Professor Matt Bentley said: "All these observations lend to the fact of raising water temperatures having an effect on our marine system.

"The swordfish is a typical oceanic fish found in temperate and tropical waters.

"The North Sea is relatively shallow and one wouldn't expect to find them here.

"It may be an instance where this individual has gone off track.

"I do not think we should attribute its presence to changes in temperatures of sea, but that is not to say it is not related."

Prof Bentley said fishermen were reporting herring and mackerel staying longer in our waters, which would be determined by food availability.

He said: "If you get warming, you get an increase in phytoplankton, which provide resources for bigger fish.

"It may well be that the temperature and climate changes are affecting patterns of smaller organisms and we could be noticing the changes in large organisms as a result."

Prof Bentley said catches of red mullett and sea bass were increasing in the North Sea, where they were not normally found.

He said: "If the warming increases, one can expect to find the sort of fish holidaymakers may see in fish markets in Spain, rather than tropical fish, in our waters."

A Newcastle University project last year noted 614 whales and dolphins off the region's coast in 12 months.

Six different species were reported from Northumberland to Whitby, North Yorkshire.

They were harbour porpoises, common dolphin, bottlenose dolphin, risso's dolphin, long-finned pilot whales and white-beaked dolphin, with one group of 250 sighted off Cullercoats.