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Marine Life of Pembrokeshire Species Focus The Common Lobster, Homarus gammarus is found in rocky habitats living in holes from the lower shore down to 60m water depth. They have huge front claws which are used to crush and slice their prey which includes mussels, crabs, sea urchins and polychaete worms. They are naturally a beautiful blue colour.
Previous Events On Tuesday 5th May the Pembrokeshire Outdoor Charter Group ran an environmental coasteer training event for outdoor instructors in Pembrokeshire. Myself and Sid Howells of CCW provided expertise on marine life and geology respectively. We had a wonderful few hours exploring the caves and exposed rocky coast at St Nons. Here are some of the marine plants and animals we saw:
Barnacles are hermaphrodites but require cross-fertilisation. A long penis is used to inseminate neighbouring barnacles. The fertilised eggs are then brooded inside the barnacle 'shell' over winter. The eggs hatch in the spring and are released as swimming larvae which feed on plankton for about two months. The larvae settle and attach themselves to the rocks during April and May and grow into miniature forms of the adult. They live for 3-6 years. Barnacles feed by extending thier feathery legs into the water and filtering out plankton.
Sea belt or Sugar kelp, Saccharina latissima A large leathery brown seaweed with a long undivided frond which has a distinctive frilly margin.It lives for 2-4 years and grows quickly during late winter to early spring.Young plants have a delicious nutty flavour!
Bread crumb sponge, Halichondria panicea This sponge is found in damp habitats on the shore such as under boulders, on overhangs or in rockpools. The green coloration is due to tiny symbiotic algae living in the tissue of the sponge. Sponges feed by filtering suspended particles out of the water and thrive where there are strong water currents.
Velvet horn, Codium tomentosum A solid spongy green seaweed found in rockpools at exposed locations. The sponginess is caused by an accumulation of gas within the medulla of the seaweed and serves to float the thallus up towards the light. It occurs mainly in the south-west of Britain and is becoming quite rare.
Irish moss or Carrageen, Chondrus crispus A small red seaweed found on the rocky shore and in rockpools. It is highly variable in appearance depending on how exposed the shore is to wave action and may turn green in strong sunlight. The fronds may also show a purple iridescence underwater, as shown in this photograph.
Strawberry anemone, Actinia fragacea A large anemone found on rocky shores, in south and west Britain.Often found in shaded places with the tentacles contracted, as in this photograph. The red column with small green spots give the appearance of a strawberry, hence the common name. When the tide is in the anemone will extend it's tentacles and catch planktonic prey using microscopic stinging cells.
Pepper dulse, Osmundea pinnatifida A small edible brown seaweed (up to 8 cm long) with a peppery after-taste; perfect for a salad garnish! Common on the rocky shores of Pembrokeshire and elsewhere in the UK.
Previous Species Focus species: The Blue-rayed Limpet, Helcion pellucidum lives on the fronds and stipes of large kelps and other seaweeds on which it feeds. Although it only reaches a size of 15mm long, it is very striking due to the series of peacock-blue dashes on its shell. If you want to learn more about this species click on this link.
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