Somerset Wildlife Trust

Work For Us|

Somerset Wildlife Trust Summer Coastal Survey 2013

 12th Aug 2013

Our marine ambassador Nigel Phillips has been doing survey work over the last couple of weeks at Porlock Weir in West Somerset. The survey produced some very interesting results, keep reading to find out what Nigel found.


I was carrying out a spur off the moment rockpool survey at Porlock Weir on 2nd Aug when I saw something rapidly shooting across the pool I was standing in. Much to my great surprise this was a 20cm long European Squid. Squid are usually deep water species and you are very unlikely to see them in a rockpool. This one was almost transparent when I first saw it, with just a few browny/purple spots. As I walked towards it,  it shot across the pool again and almost instantly changed its colour by producing spots across all of its body.

More info

The Common European Squid Alloteuthis subulata is found in the eastern Atlantic Ocean as far south as North-west Africa, theNorth Sea, the western Baltic Sea, and Mediterranean Sea. In British waters it has a southerly bias to its distribution but has been found as far north as the Solway Firth and the Firth of Clyde.

Max size for this species is around 20-25 cm.

This species is normally lives at depths of around 50m and 250 m depth over sandy-muddy substrates. They feed on small fish.

They come closer inshore during the summer breeding season. The spawning season is restricted to June and July. Eggs are covered in gel and laid in strings which are attached to hard objects on the sea bed. The eggs hatch after about 2 weeks when the juveniles are 2 mm long. They first appear in plankton samples towards the end of July.


©Nigel Phillips


©Nigel Phillips


Some of our SWT marine survey team have been making regular visits to Hurlestone Point, overlooking Porlock Bay,  to watch for Harbour Porpoises,  and this has been very successful with lots of records for this species. But in the last two weeks they have also been seeing Sunfish which are the largest/heaviest bony fish in the world. These are massive fish weighing up to 2,200 lb. They feed on jellyfish and also squid and as there have been very large numbers of Moon jellyfish appearing in Porlock Bay it is no real surprise that this huge fish has turned up off Somerset’s coast.

More info
The ocean sunfish, Mola mola, or common mola, is the heaviest known bony fish in the world. It has an average adult weight of 1,000 kg (2,200 lb). The species is native to tropical and temperate waters around the globe. It resembles a fish head with a tail, and its main body is flattened laterally. Sunfish can be as tall as they are long when their dorsal and ventral fins are extended.

Sunfish live on a diet that consists mainly of jellyfish, but because this diet is nutritionally poor, they consume large amounts in order to develop and maintain their great bulk. Females of the species can produce more eggs than any other known vertebrate. Sunfish fry resemble miniature pufferfish, with large pectoral fins, a tail fin and body spines uncharacteristic of adult sunfish.



©Caroline Briggs

Nusa Lembongan Mola Mola---SUNFISH

©Wikipedia Commons


Lots of people visiting the Somerset coast have reported seeing  jellyfish this summer and the SWT marine survey team have been out searching for them.  Nearly all these jellyfish are Moon jellyfish with four pink circles showing inside them. There have been a few orange Compass jellyfish Chrysaora hysoscella and a few blue Bye By-the-wind-sailor Velella velella.

More info
Aurelia aurita (also called the moon jelly, moon jellyfish, common jellyfish, or saucer jelly) is a widely studied species of the genus Aurelia.

The jellyfish is translucent, and can be recognized by its four horseshoe-shaped gonads, easily seen through the top of the bell. It feeds by collecting medusae, plankton, and mollusks with its tentacles, and bringing them into its body for digestion. It is capable of only limited motion, and drifts with the current, even when swimming.

Adult Moon jellyfish can have a diameter up to 40 cm. The adults are either male or female. The young larval stage, a planula, has small ciliated cells and after swimming freely in the plankton for a day or more, settles on an appropriate substrate, where it changes into a special type of polyp called a "scyphistoma", which divides by strobilation into smallephyrae that swim off to grow up as medusae. There is an increasing size from starting stage planula to ephyra, from less than 1 mm in the planula stage, up to about 1 cm in ephyra stage, and then to several cm in diameter in the adult medusa stage

In November, when they are 3 months old and about 3 cm in length, they move out of the North Sea, returning the following spring, by which time they will have attained a length of about 5 cm. The life expectancy is between 1 and 2 years.
The species feeds on small and juvenile fishes.

Moon-jellyfish-Porlock-Nigel-Phillips©Nigel Phillips


©Nigel Phillips