A bucket, a net and a sense of adventure. Emily Baxter, North West Wildlife Trust’s marine conservation officer,says rockpooling is the ideal way to explore our coastal and marine life
Our seas and coastline can seem a vast and almost infinite place to comprehend and explore, with depths and occasional dangers that seem untouchable. With the rolling of each tide however, our rockier coasts reveal myriad ocean habitats in miniature – rockpools.
Small and fairly unassuming, rockpools are harsh and challenging habitats for the wildlife that inhabits them. When the tide retreats, wave-battered boulders, mussel-strewn crags and damp crevices reveal an array of ‘intertidal’ creatures that come alive in these few hours of respite.
Rocky shore inhabitants have to deal with huge stresses such as desiccation, an enhanced threat from predators like gulls, crashing waves and drastic changes in salinity, oxygen and temperature. These shallow pools are quickly warmed by the summer sun and in contrast, heavy rain can suddenly turn the water from a familiar brine to uncomfortably fresh.
Under these pressures, plants and animals have developed ingenious ways of dealing with the daily battle. From slimy seaweed to rock-clinging limpets, tentacle-retracting anemones to cave-dwelling crabs, every creature has its own method of survival.
Not the barren places you might expect, rocky shores can be incredibly diverse and bursting with life and an afternoon rockpooling is one of the best ways to get up close and personal with some of the best of British wildlife.
Here is our brief guide to just some of the creatures you might discover:
Hermit crabs are always a crowd-pleasing find, but these timid and reclusive crabs can actually be real brutes! Lacking their own armour in a hard outer shell, they use the discarded shells of other animals to protect their soft bodies. As a result, when the crabs grow they must find a bigger shell that comfortably fits, but not too big they can’t carry it around. With the best shells at a premium, fights can break out over ‘shell envy’, with the most aggressive contenders grabbing hold of their opposition rocking them violently until the crab gives up its home. Hermit crabs can also be picky about the colour of their shell, selecting those shells which blend in best with their backdrop.
Vibrant sea anemones may look beautiful and serene sitting sedately in rockpools, however this is all a façade. Beneath the water there is a battle of wills over space. Some, like the beadlet anemone, have specialised defensive tentacles in addition to the those used to harpoon their prey. These bright blue bead-like tentacles are used to good effect against their counterparts. Sensing another anemone close by, they slowly slide across the rocks and wage war, striking the other anemone with their stinging tentacles. This toing and froing can continue for hours or days until one of them finally gives up or even dies.
Often considered one of the less inspiring of rocky shore animals, limpets also undertake a fight for territory, suffering fates including being eaten alive. When rocks are covered by water, these molluscs set off to find food, using their rasp-like tongue to scrape the fine algal film off of the rocks and ‘graze’ down young seaweeds like herds of cows in the rockpool. However, even this can cause ructions.
Like much in the world of the rockpool, the fight is always for territory. Flipping over other limpets with the edge of their shells and tossing them out of their feeding area is a popular tactic. After all this feeding and fighting they are naturally keen to get back to somewhere safe which is achieved by smelling out their own tracks and retracing their movements back to their spot on the rocks called a “home scar”. This small depression in the rock is ground out with their shell to provide a tight fit, allowing them to clamp down and stay wet when the tide is out.
If competing against other limpets isn’t bad enough, they also have to cope with the threat of dog whelks, a bully twice their size. Using a modified radula (tongue) they bore a hole into the shell of the limpet with the help of a shell-dissolving chemical, before secreting digestive enzymes and paralysing chemicals turning the soft body of their prey into a grizzly soup. Look out for empty shells found on the beach with these small holes – revealing that the dog whelk was responsible for sealing its fate.
The rockpooling code
1. Put all creatures back where you found them
2. If you turn over rocks and stones, carefully put them back to cover the animals without squashing them
3. Don’t leave animals in buckets or trays of water for too long (they may overheat), and replace them once you have looked at them
4. Don’t put wildlife from rockpools (salt water) in freshwater
5. Don’t use spades or other tools to prise off creatures attached to the rocks
6. Be aware of where you are and the incoming tide
Where to go
Hilbre Island/West Kirby: Offshore from West Kirby on the Wirral, hundreds of stunning rock pools are exposed at low-tide across the Hilbre Island group, providing some of the best rockpooling around. Follow the guidance of lifeguards to ensure you do not get stranded. The rockier shores of West Kirby itself offer more accessible opportunities for those who prefer not to make the walk over the sands.
New Brighton: Another easily accessible area, check out crevices and small pools around Fort Perch Rock and other rockier outcrops.
Birkenhead:
Rockpooling needn’t be on our natural coastlines, and the artificial shores around Birkenhead still provide opportunities to explore rockpool habitats that are man-made.
