Identification - the harbour porpoise is the only true porpoise species found in European waters. It is the smallest of the British cetacean (Dolphins and Whales) with a total length of 1.5 to 2 metres. It has a small triangular dorsal fin in the centre of its back. It is dark grey with a paler underside, has a small round body with a blunt head and no beak.
General ecology - the harbour porpoise is most often seen within 10km of the shore in small groups or pods of 2-3. They are around all year but more often seen between July and October. They are shy and are unlikely to bow ride (play in front of boats) or breach (leap out of the water). They are found in low numbers around the Essex coast but were probably more common 50 years ago. In 2002, most of the sightings were off the north Essex coast especially the Tendring Peninsular, Jaywick, Clacton and Holland on Sea. The main threats to them are possibly drowning in fishing nets, pollution and fishing.
Surveying tips - The harbour porpoise can be observed from the shore or from a boat. Other cetaceans (Dolphins and Whales) that may be encountered around the Essex coast are Bottlenose Dolphin, White - beaked Dolphin, Longfinned Pilot Whale and the Minke Whale. Records for these are also welcome.
Since 1999 a recording card, available from Essex Biodiversity project, has been used for recording all of the cetaceans. Dead sightings are useful as well and should be recorded. Essex Biodiversity project also has a listening device called POD that can be deployed to record sonar calls.
Photo - Essex Wildlife Trust