A Rockpooling Tour of the British Coastline Quiz

Answer: Sea slater

The most common sea slater you will see on British coasts is Ligia oceanica, which can grow up to 3cm in length. Its colour varies from green to grey, and this species is generally a more common find at night, as it is a nocturnal feeder. It is an omnivore, and feeds on many species of seaweeds (such as Bladder wrack (Fucus vesiculosus)), diatoms (a group of algae), and living debris.

Answer: Sand hoppers

Sand hoppers are abundant on the extreme upper shore, and prefer shelter underneath chalk rocks. They feed on rotting seaweeds washed up by the tide. If disturbed, which they most certainly will be if you turn over their rock, they will jump erratically away as a defensive ploy to keep out of the mouths of predators.

Answer: Green shore crab

The green shore crab is a well-known crab species in Britain. The crab's colouring can vary, with red, brown and grey variants also found. The crab's colour variation is a combination of environmental and genetic factors. The crab is often found on the upper and middle shore, and feeds on many bivalve organisms such as mussels.

Answer: Pagurus bernhardus

Pagurus bernhardus can be commonly seen on all British coasts, and is also one of the larger British hermit crab species, with carapace lengths reaching 35mm, and a right pincer that is much larger than the left. The hermit crab often occupies whelk or winkle shells, and will search and move into a bigger shell once it outgrows its current shell.

Although they are commonly found on the upper shore, larger examples of the Pagurus bernhardus species are usually found on the lower shore and out in the deep ocean, where they are often trawled.

Answer: Long-spined sea scorpion

The long-spined sea scorpion, or bullhead, is a stocky fish with a large bony head that tapers toward the tail. It can grow to over 20cm in length, but is more commonly found at a length of 10-15cm. The spines on its dorsal fin and head are not poisonous, but are sharp and meant for protection against predators.

The colours of this species are incredibly variable, with light-coloured examples preferring sand as a camouflage, and dark-coloured examples better suited to brown algae camouflage.

Answer: Flat periwinkle

There are four recognised species of periwinkle on British rocky coasts. The flat periwinkle can be distinguished from the other three species by its flattened spire. The edible periwinkle, small periwinkle, and rough periwinkle are the other three species, and all can be found on the upper and middle shore.

Answer: Common starfish

The common starfish, as the name suggests, is the most common starfish found on British coasts. It is frequently found on all areas of the shore, although larger specimens are more frequently found on the lower shore and out to sea. Interestingly, common starfish can suffer from genetic mutations that result in them having more or less than the usual five arms (in most cases this mutation results in the starfish having four or six arms).

Answer: Lesser sand eel

Lesser sand eels are a common site in large rockpools in summer. They are often seen in large shoals, mainly for protection, as they are keystone species in the ecosystem and are the prey of many common sea birds. Typically, this fish does not exceed 8cm in length.

Answer: Cancer pagurus (edible crab)

The edible crab has the classic 'pie crust' edging to its carapace, and is often identified by this piece of information alone. Mature adult species can grow to be very large, up to 30cm in width. These are often found in deeper waters though, and are frequently trawled.

In rockpools, typical specimens of Cancer pagurus are about 8-12cm across the carapace. Juveniles can be found almost anywhere on the shore, even amongst kelpweed holdfasts (roots).

Answer: Velvet swimmer crab

The velvet swimmer crab has a fearsome rockpool reputation as an angry crustacean. Indeed, it has been nicknamed the devil crab in some parts of the country. The crab will fiercely defend its territory and will snap its claws, or chelipeds, at anything that tries to get too close.

This crab typically grows to around 8cm maximum carapace width, but is more often found with body widths of 4-6cm.

Answer: Lower shore

There are four species of brown algae that are excellent for identifying which area of the shore you are on. Spiral wrack is typically most abundant on the upper shore, bladder wrack is most abundant on the middle shore, serrated wrack is most abundant on the lower shore, and sea belt (a type of kelp weed) is most abundant in the sublittoral zone (this area is even lower than the lower shore and is only exposed to air during the lowest spring tides.)

Answer: European lobster

The European lobster can grow to well over 50cm in length, but most are fished before they reach such a size. When you are rockpooling, you are most likely to see lobsters ranging between 15-30cm in length (not including the claws). Large mature adult lobsters are usually found in much deeper waters.

Answer: Male lumpsucker

Breeding occurs from February to May, and the male lumpsucker establishes a territory for the eggs, and then spends several weeks guarding and ventilating the fertilised eggs until they have hatched. The females are larger than the males, and are usually blue/grey in colour. Males grow to 30cm in length, females up to 50cm.

Answer: Yes

Lumpsucker caviar, or lumpfish caviar, is simply the fully ripe egg mass of the female lumpsucker (known as 'roe') which has been processed and salted. Most often, the naturally pale eggs are dyed black or orange before going on sale as caviar.

Answer: No

Before you go rockpooling anywhere, make a note of what time low tide is. Alarm your watch or mobile phone if necessary. If you stay out on the lower shore for too long, you are at serious risk of being trapped by the incoming tide. The lower shore may harbour many interesting marine organisms, but it is also the most dangerous area of the shore, and safety must always come first when rockpooling.

I hope you enjoyed the tour!