Marine Sightings: Summer 2010

A Trigger fish was caught and released at Kimmeridge on 12th September. These fish generally appear in late summer and are thought to disappear in the winter. Being a warmer water species they cannot cope with the cold winter temperatures.

Bottlenose Dolphins (Tursiops truncatus) seen just off Durlston head. This is a common place to spot these animals but every sighting is just as exciting! 6 were seen on 02/09/10 and 2 more on 08/09/10.

Also on 02/09/10 a Sunfish (Mola mola) was spotted from Durlston Head. These animals are usually identified by their big triangular fin flapping from side to side out of the water as they slowly propel themselves along. Quite a rare sighting along the Dorset coast they are normally more abundant in oceanic waters where they mainly feed on jellyfish.

On 19/08/10 a Seal was spotted just off Tilly Whim. The exact species of seal remains unknown but common seals and grey seals have been spotted in Dorset previously, though not common quite a few sightings have been reported this year especially in and around Poole harbour.

Throughout June and July further sightings of juvenile Undulate rays (Raja undulata) have been reported from the south side of Swanage Bay supporting the belief that both Swanage and Studland Bay are a nursery area for this endangered species. Any sightings of these creatures would be of great interest and details will be passed onto the Shark Trust.

Two separate sightings of rare Sea Lampreys (Petromyzon marinus) were reported in June and July, one photographed attached to a grey mullet in Weymouth marina and the other a breeding pair videoed nest-building on the River Piddle at Wareham. They are a very primitive form of fish being without jaws, using their sucker mouth and rasping teeth to feed off other fish. They migrate up rivers to spawn and although rare their populations are thought to have recovered in recent years as rivers have been cleaned up.

In mid-July a baby Risso’s dolphin (Grampus griseus) was discovered dead on Chesil Beach. Looking very fresh it was immediately taken away for a post mortem examination to find the cause of death. Sadly it is believed the new born became separated from its mother and was unable to suckle.

Following their first recording in Dorset under Swanage Pier in 2007, and a single record of one in Studland Bay in 2009, Anemone Shrimps (Periclimenes sp.) have now been found in Worbarrow Bay and at Ringstead. These small, transparent shrimps live among the stinging tentacles of snakelocks anemones where they are protected from most predators. They had not been recorded north of the Channel Islands until their discovery in Dorset.