Harsh winter conditions and climate change are being blamed for an increase in the number of deaths of porpoises off the Suffolk coast this year.

At least six of the fishes royal have been washed up in the Felixstowe area alone in the past three months.

Council workers and coastguards recovering the bodies have been surprised at the good condition the animals have been in.

A spokeswoman for British Divers Marine Life Rescue, which rescues stranded marine mammals, said there had been an increase in porpoise deaths this year but did not believe there was any single cause.

She said: “It is a widespread situation. We have seen an increase in deaths all the way along the east coast from Northumberland to Kent, including along the coast of Suffolk.

“It was a very harsh winter and the sea has been much colder and this may have caused them problems.”

Dr Jean-Luc Solandt, senior biodiversity policy officer with the Marine Conservation Society, said lack of food and changes in food location, possibly due to climate change with many fish moving north into chillier waters, was a possible cause of the extra deaths.

Other reasons included disorientation, perhaps because of persistent pollutants affecting the cetaceans’ brains, and “ramming” by other cetacean species.

Sometimes they were tangled in fishing nets or if they came close to shore could be caught in propellers.

Because porpoises are classed as “fishes royal” – along with whales, dolphins and sturgeon – the Receiver of Wreck has to be informed whenever one is washed up on a beach.

The bodies are sent to the Zoological Society of London for post mortem examinations.