Big Rockpool Ramble: The Results!

Butterfish - Ballyholme Beach - Phil W

Thank you to everyone who took part in the Big Rockpool Ramble 2020. We had a massive response and were delighted to see so many people and families exploring the incredible marine wildlife around our shores.

We know very little about our rocky shore wildlife, but your Big Rockpool Ramble records will help to plug this gap. Over time, we hope to build up a better picture of the species around our coasts and to understand how they are changing over time, the effects of invasive species and the impact of climate change. 

In total, you recorded over 79 different rocky shore species. 

 

Here are the TOP TEN most common species that you found during the Big Rockpool Ramble 2020: 

#10 Common prawn (Palaemon serratus)

Difficult to spot as they dart back into the darkness, the common prawn is found in rockpools and under boulders, scavenging on whatever they can find. They have characteristics red tiger strips along their body and a serrated rostrum along their heads. Females can carry up to 4000 eggs along their legs!  

Common prawn, Ballyholme Beach, Phil W

Common prawn, Ballyholme Beach, Phil W

#9 Common periwinkle (Littorina littorea)

Periwinkles are sea snails and this is the largest one that we find around our shores, reaching up to 5cm in length. They are common on rocks, in crevices and hidden within the seaweed, especially around the middle and lower areas of the shore. They move over the rocks to feed, using a rasping tongue called the radula to scrap tiny bits of algae off the surface. 

Common periwinkle, Newtownabbey, Dakota R

Common periwinkle, Newtownabbey, Dakota R

#8 Brown crab (Cancer pagurus)

A large crab with a brown shell and black-tipped claws. They can be identified by the ‘pie crust’ edge to their shells. This is a predatory species which feeds on mussels, whelks, periwinkles and smaller crabs. They are active at night to avoid predation from seals and large fish during daylight hours. The brown crab is an important commercial species across Europe.  

Brown crab, Ballyholme Beach - Phil W

Brown crab, Ballyholme Beach - Phil W

#7 Bladder wrack (Fucus vesiculosus)

Bladder wrack is a brown seaweed, distinguished by their paired air bladders. These give the plant buoyancy when covered by water, allowing them to reach the sunlight to photosynthesize. Bladder wrack is an important species on the shore as it provides food and shelter for many other animals. It has been found to contain anti-ageing properties and is used in some face creams. 

Bladder wrack, Kilclief, Strangford, Rosa & Martha K

Bladder wrack, Kilclief, Strangford, Rosa & Martha K 

#6 Barnacles (Various species)

They are many different kinds of barnacles to be found attached to the rocks around our coast. They might look quite plain but they are actually tiny crustaceans, closely related to crabs. When the tide comes in, they open their central plates to stick out feeding arms and catch tiny bits of food from the water. The acorn barnacle (Semibalanus balanoides) is the most common species around the coasts of the UK and Ireland.  

Barnacles, Killowen, Carlingford Lough, Amy M

Barnacles, Killowen, Carlingford Lough, Amy M

#5 Hermit crab (Pagurus bernhardus)

The second of three crabs on our top ten list, the hermit crab lives inside the shell of sea snails, like whelks and periwinkles. They have tough front claws but a soft body which is curled up and protected within the shell. As they get bigger, the hermit crab will move house, finding a larger shell to live in. Sometimes, when two hermit crabs meet, one might attempt to steal the shell of the other, fighting it to draw it out of its home before it can steal the shell for itself. 

Hermit crab, Bath Street, Portrush, Brenda T

Hermit crab, Bath Street, Portrush, Brenda T

#4 Beadlet anemone (Actinia equina)

The beadlet anemone looks like a dark red blob when the tide is out, but find one under water and you might see it fully extended, displaying its tentacles to catch food from the water. They use these to catch shrimps, small fish and crabs. The beadlet anemone is aggressive to its neighbours and will fight off other anemones from its patch with stinging cells found in the ring of bright blue beads at the base of the tentacles.   

Beadlet anemone, Kearney Point, Lucy W

Beadlet anemone, Kearney Point, Lucy W

#3 Common starfish (Asterias rubens)

Usually growing to around 30 cm wide, this is the most commonly found starfish around our shores. They are active predators, feeding on worms, mussels and clams. They use tiny tube-feet on their underside to prize open shells before inserting their own stomach into the shell and dissolving the soft body within. Not weird enough? Starfish sometimes shed an arm to escape a predator but can regrow the lost limb! 

Common starfish, Ballyholme Beach, Phil W

Common starfish, Ballyholme Beach, Phil W

#2 Common limpet (Patella vulgata)

Our second most common Big Rockpool Ramble species is the common limpet, easily spotted as small cone-like shells attached to rocks around the coast. They might seem a bit dull when the tide is out, but when they are covered by water, they move all around the rock surface eating algae. Their tongue, which they use to scrape food off, is the strongest biological structure known to man! After this feeding actively, they always return to the same spot on the rock, known as their ‘home scar’ which has been worn away over time by the edge of their shells.  

Common limpet , Bath Street, Portrush, Brenda T

Common limpet , Bath Street, Portrush, Brenda T

#1 Shore crab (Carcinus maenas)

Our Big Rockpool Ramble winner! 

The most common crab around our coasts, the shore crab is distinguished from the brown crab by the five serrated ‘teeth’ on the edge of its shell which sit to either side of the eyes. They aren’t picky eaters, feeding off seaweeds, mussels, barnacles and even small crabs. When you find one, you can tell whether it’s a boy or a girl by looking at the triangle shape on the underside of their shell. Males will have a thin, pointy triangle but females have a much broader shape, which they use to carry their eggs.  

Shore crab, Holywood, Aaron L

Shore crab, Holywood, Aaron L

What’s next? 

The species records from the Big Rockpool Ramble 2020 will be shared with CEDaR, the local biodiversity records center. We will add to this information each year

Join us next summer for the Big Rockpool Ramble 2021!