Wildlife to spot on the South West coast this summer
As we look forward to summer, who can resist the idea of heading to the South West coast for the pure joy of rock pooling?
Rock pools are magical worlds full of alien creatures. You can visit the same rock pool over and over again and still see something new every time. It’s just a case of heading to the shore, hunting out a pool and having a look – you’re unlikely to be disappointed.
The common limpet
The common limpet (Patella vulgate) is an edible species of sea snail with gills. It is found attached to rocks from the high shore to the water all along the coast and it feeds off algae.
Its white shell is conical or ‘dish’ shaped with no obvious coiling and it has a strong muscular foot. The limpet is capable of locomotion instead of being permanently attached to a single spot, but when it needs to resist strong wave action it can cling extremely strongly and it is often is very difficult to remove it from a rock without injuring or killing it.
Did you know? The common limpet has 1920 teeth in 160 rows of 12 teeth each and they are considered the strongest natural material ever tested, significantly higher than spider silk. Artificial structures based on limpet teeth may have applications in high-performance engineering, such as aircraft fuselages and the bodies of Formula 1 racing cars.
The common periwinkle
The common periwinkle (Littorina littorea) is another species of small edible sea snail with a dark pointed spiral shell. Like the limpet, it is primarily an algae grazer, but it will feed on small invertebrates such as barnacle larvae.
The periwinkle, often known as a winkle, is believed to have been an important source of food since at least 7500 BC. It is usually picked off the rocks by hand or caught in a drag from a boat and is widely eaten in coastal areas. It is commonly sold in paper bags, boiled in seawater and eaten with a pin to enable the extraction of the soft parts from the shell.
The common starfish
The common starfish (Asterias rubens) is the most familiar starfish in the UK and usually grows to between 10-30cm across, although larger specimens have been known. It is usually orange or brown, sometimes violet, has five tapering arms, with white spines running along the centre upper surface and rows of small tube feet underneath that help it move and feed.
When feeding on a mollusc such as a mussel, the starfish inserts a fold of its stomach and starts digesting. It then brings its stomach back to its rightful position with the food inside. The starfish has a well-developed sense of smell and can detect the odour of prey and crawl towards it. It lives for about seven to eight years.
Large numbers of starfish can sometimes be washed up onto shore. The cause of the mass strandings is unknown but bad weather and storms out at sea coupled with higher than usual tides may be to blame.
The hermit crab
The hermit crab (Paguroidea) is a favourite of rock pool enthusiasts and is widespread around the coast. There are more than 1,000 species and despite the common name, they are more closely related to lobsters than true crabs.
You can never tell if that old whelk or periwinkle shell is home to one of these crustaceans. A hermit crab appropriates shells to protect its soft twisted abdomen from predators. As the hermit crab grows, an overly snug shell is abandoned in favour of a larger abode.
One empty shell can trigger a property rush as crabs gather and simultaneously pass discarded shells down the housing chain to smaller individuals. If kept together they may fight or kill a competitor to gain access to the shell they favour
Hermit crabs are sometimes kept as pets, but only live a few months in captivity, whereas some species can live over twenty-years in the wild. They are sociable creatures, often living in large colonies, need deep damp sand in which to molt, fresh (not tap) water and a humid atmosphere in order to survive.
The beadlet sea anemone
The beadlet sea anemone (Actinia equina) is common on all rocky coasts around Britain. It looks a lot like a plant and is named after the beautifully-colored anemone flower, but it’s actually a marine animal closely related to coral and jellyfish. It consists mostly of a hollow column with a single opening, the mouth, used to ingest food and expel wastes and stinging tentacles at the top.
The sea anemone waits for small fish and other prey to swim close enough to get caught in its stinging tentacles. It doesn’t always stay in one place, though. It can slide slowly along the sea floor or swim by moving its tentacles.
Did you know? Sea anemones have been known to have symbiotic relationships with hermit crabs, each animal benefiting from the relationship. The sea anemone is able to catch more food by taking a ride on a hermit crab as it moves it around from place to place. The crab gets protection because the sea anemone’s stinging tentacles scare away predators.