Species

The rock pool shrimp (Palaemon elegans) is very common in our rockpools and is often confused with other shrimp species like the common prawn (P. serratus). P. elegans has a transparent body with dark brown stripes along its carapace and six abdominal segments with yellow and blue banded legs. They can be differentiated from other shrimp species by their rostrum (a long appendage that looks like the shrimp’s nose and has several serrations). P. elegans has a much straighter rostrum than P. serratus with 8-9 serrations, 2-3 are behind their eyes. These shrimp can get to 63mm in length but are usually found much smaller than that; around 30mm.

The Painted topshell (Calliostoma zizyphinum) is a beautiful mollusc that can be found on many sheltered rocky shores in the UK. This mollusc has a distinctive conical shell and a flat base which can reach sizes of up to 3cm, both in height and width! This shell is covered in roughly 10-12 whorls usually with a white base colour that is marbled with yellows, browns, pinks and purples. If you’re really lucky, you might be able to see the snail itself, which is just as colourful. You’ll notice that these shells are very clean, this is because the snail uses its extendable foot to remove any algae – around 2 times every 24 hours.

Barnacles, or Cirripedia, are one of the most abundant groups of species present on many rocky shores. However, to the untrained eye, the grey-white carpet of miniature creatures coating the rocks underfoot can seem an identification nightmare. Recently, we were extremely fortunate to have barnacle expert Mike Puleston give us a talk full of the tricks of the trade when it comes to UK barnacle ID.

The Atlantic bobtail squid (Sepiola atlantica) is truly a hidden gem of the rocky shore. These camouflage wizards are so easy to overlook that they are usually only spotted when accidentally disturbed, spending much of their time buried in the sand with only their eyes peeking out.

The edible crab (Cancer pagurus), also known as the pasty crab to those of us in Cornwall or the brown crab is a common crab found under rocks along our coasts. They get their name from their reddy-brown colour and a large oval-shaped carapace that is crimped around the edges to resemble a pie crust.

Also known as the common blenny, the shanny is one of the most common and characterful of all rock pool residents. With their downturned smile and discerning gaze, these fierce fish are not to be overlooked!

Wrack are a family of common seaweeds found on many UK coasts. The name ‘seaweed’ is rather deceiving as the wracks are actually a type of algae. There are three main types of seaweed; red (Rhodophyta), brown (Phaeophyta) and green (Chlorophyta), wracks are brown seaweed and are branched and have ribbon-like fronds

There are many different types of beautiful fish that can be found in UK rock pools. This guide goes through some of the most common species you might find.

Beautiful yet deadly, anemones are some of the rock pool’s most ferocious inhabitants. Here’s a snapshot of everything you need to know to tell these colourful critters apart.

I’m fascinated by nudibranchs and hopefully throughout this blog you will learn many new interesting facts about them! Don’t forget to keep yours eyes peeled whilst out rockpooling!