The Rocky Shore
The rocky limestone ledges that stretch out below the shingle ridge provide an excellent seashore habitat for a wide variety of marine animals and seaweeds. There are lots of rockpools, cracks and crevices which are teaming with life when you look closely.
Some of the species you are likely to find include limpets, anemones, shore crabs, bladder wrack, barnacles and sea lettuce.
Common Limpet (Patella vulgata): Limpets, large dome-shaped snails that can live over 15 years, are important herbivores, feeding on microscopic algae which covers the rocks. They feed by scraping their sandpaper-like tongue (radula) across the rock surface. The radula is covered in many iron toughened teeth which acts like a file and is one of the toughest biological materials known. Each sweep of the radula removes fine algae and leaves a grazing mark on the rock.
Using their large muscular foot, limpets clamp tightly to the rocks at low tide to prevent drying out. As limpets settle down, they rotate the shell and grind it into rock which produces a good fit but also, on death, leaves a scar on the rock surface. The sexes are separate but as in many snails they often begin life as males changing to a female as they get older. Sperm fertilise the eggs externally in the seawater. The eggs hatch into planktonic larvae which live in the sea for several weeks before settling out on to the shore.
Beadlet Anemone (Actinia equina): Anemones are carnivores feeding upon crabs, shrimps and small fish. Their 200 or so sticky tentacles are covered with stinging cells that paralyse their prey and pass it to their mouth.
This anemone species can survive on the upper parts of shores in rockpools or even in moist crevices. It does this by retracting its tentacles reducing its surface area and trapping water inside its body. Its mucus covered body reduces water loss yet further.
Although they are attached to the surface they can creep slowly along and can get quite territorial, nudging each other until one moves. They reproduce asexually by budding internally to produce many small genetically identical anemones.
The European Eel (Anguilla anguilla): If you are really lucky you might find an eel on the beach which has been temporarily trapped in a pool or could be on its way to the sea from the stream beyond the pebble ridge. These are a different species to the Conger Eel, and are an important part of both marine and freshwater ecosystems. They feed on dead and decaying animals – helping to recycle nutrients. They are also important food for otters and for birds such as herons and egrets. European eels have an extraordinary life cycle. They start as eggs in the Sargasso Sea near Bermuda and spend 18 months floating on ocean currents towards the coasts of Europe and North Africa. They enter rivers and lakes as baby eels known as elvers or ‘glass eels' (due to their transparency) and spend anything from 5 to 20 years feeding and growing into adult eels. They then return to sea and swim 3000 miles for over a year back to spawn in the Sargasso Sea.
The Somerset rivers and wetlands are ideal habitat for eels. However, human made barriers are now found across many rivers meaning that across Europe eels can only access 10% of the habitats they used to. Numbers as a result have reduced by 90 – 95% over the last 40 years making eels now officially ‘critically endangered'.
The Shore Crab
Shore Crab (Carcinus maenas): Crabs are highly mobile carnivores and scavengers and will eat most other seashore animals especially sea snails, which they hold in one claw and then snap off the edge of the shell to get to the softer parts.
Their carapace has a variety of colours which can reflect the habitat they live in, although as they age, they become mainly green and then red when they are fully mature. They are very adaptable animals able to cope with varying salinity and temperature and can be found quite high up the shore where they avoid stress by sheltering under seaweed and stones.
The crab's abdomen is folded under the body and in males is narrow whereas the female it is wider. If you find a crab and carefully turn it over see if you can work out which sex it is. When the female is fertilised, she lays up to 200,000 eggs which she the carries underneath the abdomen. The hatched larval stage lives in the plankton, going through a series of moults before settling on to the shore.
There is a coastal tradition for newly wed fishermen to wrap a red ribbon around a crab claw and bury it beneath the marital home lintel or door step on the night of the wedding. This not only preserves the sanctity of the union but guarantees the safe passage of the husband home from working on the sea.
These tiny conical shelled structures (5-10 millimetres) stuck to the open rocks are crustaceans - relatives of shrimps, crabs and lobsters. They are made up shell plates around a central opening which is sealed up at low tide. At high tide feathery modified legs stick out of the plates and sweep back and forth filtering food (plankton and detritus).
Barnacles start life as a planktonic larvae which settle out on the shore after about six weeks. The young barnacle wanders about on the shore looking for a suitable place to attach. Once the animal has found a good spot it stands on its front end, permanently glues itself down and then grows into an adult staying in the same spot for the rest of its life.
Several different species of barnacle are commonly found on Somerset shores, but most of them are not as abundant far up the Bristol Channel as Kilve, may be due, in part, to the muddier waters on this shore, however there are plenty of individuals of the non-native star barnacle (Austrominius modestus). This arrived in the English Channel from Australia in the 1940's, probably brought over in the holds of ships. It has spread quickly around the UK coast. Unlike native barnacles it has a tolerance of silty water and lower salinity.
Bladder Wrack (Fucus vesiculosus): this common seaweed is one of four species of brown wracks found at Kilve. It has pairs of air bladders in its fronds which allows it floats up towards the light at high tide, whilst remaining firmly attached to the rocks by a small pad called a holdfast.
The wracks flop over into a moist heap during low tide to reduce water loss. There are separate male and female plants with swollen reproductive structures located at the ends of the fronds containing sperm or eggs. Once the eggs are fertilised the females release many tiny spores into the plankton which eventually settle on rocks and grow into adult wracks.
The Sea Lettuce
Sea Lettuce and Gut Weed (Ulva spp): These closely related light green algae either form flat sheets (sea lettuce) or long crinkly tubes (gut weed). They are often more abundant in the summer as they need more light than brown seaweeds.
They can survive less salty water and like high nutrient levels. In early summer nitrate levels can become very high due to fertiliser run off from farmland. This can cause an explosive green algae, growth which is often seen at Kilve where the freshwater stream runs down the shore.
These are one of many types of seaweed that are edible with the right preparation!
Walk up the grassy headland eastwards (with the channel on your left).