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Timid visitor spotted at Ipswich docks
by Andy Hollis
Evening Star - Ipswich
28th November 2003
SWIMMING through the water of Ipswich Docks today, a dorsal fin has been spotted which may bring marine wildlife enthusiasts flocking to town.
But rather than a great white shark like Jaws, this fin probably belongs to the much less ferocious, harbour porpoise.
Star photographer Simon Parker captured the timid visitor on camera yesterday afternoon.
Although common around the coast of the UK, these mammals are much more timid than their dolphin relatives, and so are much harder to spot.
At around 1.5m in length they are much smaller than dolphins and they tend to be found alone or only in small family groups.
Although porpoises have occasionally been seen riding a ship's bow wave, they tend not to approach boats or people and are not as playful as dolphins. The best chance of spotting one of the elusive animals is when it comes to the surface to breathe.
Suffolk Biological Records Office spokesman Martin Sanford said: "It is surprising and very exciting to get porpoises that far up the river.
"They are only rarely seen in the Estuary. It is probably a youngster that has been separated from the family group and got lost. Or it could be an injured adult.
"The species are declining internationally, due to being caught in fishing nets and due to pollution."
Unlike fish that get all the oxygen they need from the water, porpoises must breathe air, so they must surface every few minutes to catch a fresh breath through the blowhole. Dives of up to 12 minutes have been recorded.
The porpoise's visit is an indication that the River Orwell is clean and healthy as these animals are very sensitive to pollution and will avoid dirty waters.
The river also attracted swarms of hundreds of jellyfish, and large mullet feeding on the pontoons over the summer.
Whales, dolphins and porpoises all belong to a group of mammals called the Cetaceans, the porpoises being the smallest.
Unlike their dolphin cousins who have peg-like teeth, porpoises have flatter spade-shaped ones.
Porpoises communicate and navigate using sonar emitting pulses from the their foreheads.
Their diet is a variety of fish, squid and octopus.
Harbour porpoise can live to around 24 years old.
Harbour porpoises are eaten by sharks including the great white, and killer whales and there have been reports of bottlenose dolphins attacking them in the Moray Firth, Scotland.
The animals are at risk of suffocating in fishing nets and pollution.
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