Marine Ecology & Biodiversity

UK Species

Description: This starfish normally has seven arms. The body and arms have an even velvety texture and are orange-brown in colour. There is a conspicuous band of long white spines along each side of the arms. The tube feet are very long and tapering and the starfish can move very quickly. Up to 40cm or more in some localities.

Habitat: Found on sandy or sand scoured rock, gravel and mixed sediments where it feeds on other Echinoderms. It may be found from the lower shore to deep water. Individuals often bury themselves partly in gravel.

Description: This starfish normally has seven arms. The body and arms have an even velvety texture and are orange-brown in colour. There is a conspicuous band of long white spines along each side of the arms. The tube feet are very long and tapering and the starfish can move very quickly. Up to 40cm or more in some localities.

Habitat: Found on sandy or sand scoured rock, gravel and mixed sediments where it feeds on other Echinoderms. It may be found from the lower shore to deep water. Individuals often bury themselves partly in gravel.

Description: The trigger fish Balistes carolinensis is commonly known as the grey trigger fish. It is brownish green to grey in colour and reaches a maximum length of 40cm. The mouth is small and 'beak like' with fleshy lips. Body form is laterally flattened to allow manoeuvring in shallow rocky areas or wrecks that they inhabit. The first dorsal fin can be locked upright and then unlocked by depressing the second spine, the 'trigger'.

Habitat: Mainly rocky bottoms and floating wreckage at depths between 10-100 m. Common in med but sighted more and more around S.West Uk, travels up with warm currents.

PISCES

Subtidal Species

Description: This starfish has five tapering, blunt-tipped, arms covered with small, scattered white spines. Small specimens are quite stiff but larger ones are rather soft and floppy. The white spines form a definite line down the centre of each arm. Between the spines are groups of soft transparent processes called papulae. Body colour is usually brown to pale orange, in some locations this may be masked by blue or purple. In exposed habitats up to 12cm, in more sheltered sites up to 30cm across.

Habitat: The commonest British starfish intertidally and in the sublittoral. Particularly common on mussels in the shallow sublittoral and on soft sediments. One of the few echinoderms which can tolerate brackish conditions.

Phylum: Echinodermata
Class: Asteroida
Order: Forcipulata
Family: Asteriidae

Description: A small clonal anemone with a smooth column up to 15mm in height and diameter. The disc is wide, the tentacles have rounded knobs at their tips, up to 100 in number. the colour is often brilliant green, red, pink, orange, white or brown, in various combinations, usually the tentacle knobs contrast with the colour of the column. Reproduces by longitudinal fission, ie. dividing in half vertically. Sometimes the resulting anemones do not separate completely.

Habitat: Lives on rocks, occurring in shaded places low on the shore, or sublittorally down to about 50m, always in strong wave action or tidal streams. Usually occurs in large aggregations consisting of patches of similarly coloured clones

The cup-corals Caryophyllia smithii and Caryophyllia inornata also have knobbed tentacles of similar appearance, but they possess hard calcareous skeletons.

Description: The stem of this hydroid has a tough, yellowish coloured tegument. Usually the stems are clustered together and fuse with each other towards the base of the colony. The polyp colour is pale pink through to red, and consists of a central circlet of oral tentacles surrounded by paler but larger aboral tentacles. Gonothecae arise within this inner set of tentacles. Overall height 100-150mm, diameter of the polyp and tentacles about 15mm.

Habitat: A characteristic species of current swept bedrock and boulders, which may attach to other substrata such as kelp stipes.

Description: The long, sinuous tentacles of this sea anemone are rarely retracted (although retractile). The column is smooth, with a row of inconspicuous warts on the rim of the parapet. The colour of the column is brownish or greyish; tentacles are similar or bright green, usually with bright purple tips and red bases. Span of tentacles up to 200mm but usually less than that in British specimens.

Habitat: Usually found in open situations exposed to the light. On the shore in pools, on rocks or sea-weed (eel-grass or kelp) and in the shallow sublittoral down to about 20m. Snakelocks Anemones, Anemonia viridis , are found on the southern and western shores of  Britain and as far south as the Mediterranean Sea.

Phylum: Cnidaria
Class: Hexacorallia

Description: This sea anemone has a wide and firmly adherent base. The column is smooth, divided into scapus and capitulum, with a prominent parapet and fosse. The tentacles are slender, short or moderate and very numerous in large or medium sized specimens. Colour is usually white or orange, occasionally buff, yellow or reddish, sometimes bi-coloured. Tentacles usually with a white band near the base. Size up to 120mm across base and 300mm tall but many small forms 30-40mm across the base.

Habitat: Found attached to rocks, etc., from the middle shore to about 100m depth. Typically in places where there is strong water movement; often on projecting substrates such as piers, sewage pipes, wrecks, etc. Large specimens rarely occur on shore but may be abundant in the sublittoral. Small forms are frequent in brackish-water situations.

Distribution: Common on all British coasts and northwest Atlantic generally, occasional in the Mediterranean.

Phylum: Cnidaria
Class: Hexacorallia

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