Class Cirripedia : Barnacles and their allies

Class Malacostraca

Superorder Eucarida

Suborder Pleocyemata, Infraorder Caridea

Suborder Pleocyemata, Infraorder Astacidea : Lobsters

Suborder Pleocyemata, Infraorder Palinura : Crawfish

Suborder Pleocyemata, Infraorder Anomura : Porcelain crabs, squat lobsters and hermit crabs

This Phylum includes crabs, the second most important bait species in the UK, and also used for human consumption. Crustaceans are classified as shellfish, or seafish, under fisheries statute. Collection of any of these species may therefore be governed by statutory fisheries legislation, regardless of intended use.

None of the Cirripedia that occur on UK coasts are large enough to be collected for bait or human consumption. Stalked barnacles (origin unknown) have been observed on sale for human consumption elsewhere in Europe.

This is the largest class of Crustacea. Its members occur abundantly in all marine habitats, and include the familiar crabs, lobsters, shrimps and prawns. Six superorders are recognised (Hayward et al. in Hayward and Ryland 1995). Not all of these are listed below, because not all include species of commercial importance or collected intertidally.

The decapods are the largest group within the Malacostraca, which are divided into two suborders. Some authorities classify these species within suborder Natantia, the swimming decapods, and suborder Reptantia, the walking decapods. Hayward et al. (1995), however divide them on the basis of gill and leg (pereopod) structure, and larval development. Suborders Dendrobranchiata (with no species listed here) and Pleocyemata are recognised under the latter classification. Infraorder Caridea represents the only British Natantia. The reptant decapods comprise the other four infraorders of the Pleocyemata and the Dendrobranchiata.

Eight species recorded from Britain (Hayward et al. 1995). The largest, the common prawn Palaemon serratus, is valued for human consumption, and may also be used as bait. However, other smaller species will also be taken. They are usually collected by hand net in the intertidal and shallow water.

Palaemon serratus (Pennant). Common prawn. Up to 110 mm in length, and found from the intertidal (in rock pools, under ledges and in weed) to a depth of 40 m, frequent on the south and west coasts, but scarce in the north-east (North of the Thames).

Palaemon elegans Rathke. A smaller (to 63 mm) intertidal species, found under rocks and stones on all coasts (but possibly more scarce in the north).

Mentioned in passing here because these are also commercially important species - however they are predominantly sublittoral (except juvenile Pandalus montagui, which may occur on the shore).

Eleven species recorded in Britain. With the exception of the common shrimp Crangon crangon, all are either restricted to the sublittoral, or too small to be targeted for bait or human consumption.

Crangon crangon (Linnaeus). Common shrimp. A mottled grey or brownish shrimp up to 90 mm in length. Common from the mean tide level to about 50m depth on all sandy shores and sandy pools on all coasts. Collected, mainly for human consumption, with shrimping nets, and sometimes used for bait.

Two species are commonly recorded from Britain; the lobster, and the wholly sublittoral Nephrops norvegicus (Hayward et al. 1995).

Homarus gammarus (Linnaeus). Common Lobster. Occasionally found hiding among rocks on the lower shore – generally found only at the extreme low water mark (at least partly because of human collection pressure). More abundant in the sublittoral, from the Lofoten Isles to the Mediterranean, Black Sea and Morocco, where it is fished with baited pots.

Both British species are wholly sublittoral (from >20 m), taken with baited pots or tangle nets.

Eighteen species in seven genera are recorded from Britain (Hayward et al. 1995). All are adapted to living in gastropod shells. The largest (usually Pagurus bernhardus) may be collected from the shore, extracted from their protective shells, and used as fishing bait (together with other crabs). Probably used for human consumption elsewhere in Europe.

Pagurus bernhardus (Linnaeus). Common hermit crab. Reaches a carapace length of about 35 mm, when commonly found in large whelk Buccinum undatum shells. Present on the shore from mean tide level into the sublittoral, where it occasionally occurs at depths of as much as 500 m. Very wide-spread in rocky and sandy substrata all around Britain, and from Iceland and Norway in the North to Portugal in the south, and on the American Atlantic coast.

Eight species recorded from Britain (Hayward et al. 1995), mostly in the sublittoral. They have been fished (using pots) for human consumption in the UK for several years, but exported to the Continent. However, more recently squat lobsters have begun to make an appearance in fishmongers in the UK, and may be taken from the shore for human consumption. They may also be used for fishing bait.

Munida rugosa (Fabricus). Reaches an overall length of 60 mm, and carapace length of 30 mm. Attractive pinkish-red in colour. Fairly common in stony and rocky habitats from the low water mark of spring tides to 150 m on all UK coasts and elsewhere from Norway to the Mediterranean and Madeira.

Galathea squamifera Leach. A dark brownish green squat lobster, reaching an overall length of 65 mm and carapace length of 32 mm. Common on the lower shore (around the low water mark of spring tides) and in the shallow sublittoral around the British Isles and from Norway to the Azores and Mediterranean.

A large group, including several superfamilies, not all of which are listed below (this report only lists the more common intertidal species). This group includes several commercially important species and some which are routinely collected for bait – the ubiquitous shore crab Carcinus maenus is the most common of these.

All crustacea have to shed their external carapaces periodically to enable themselves to grow. Expansion of the body takes place after moulting the old carapace and before the new one has hardened. Crabs entering the moult are called peeler crabs (because their old shell is beginning to lift away from the body). After the shell has been shed, they are called soft shell crabs. Because crabs are particularly vulnerable to predators during these stages, they need to hide away under rocks or other shelters. Many anglers maintain that the hormones released by moulting crabs are particularly attractive to fish, thus making peeler crabs very valuable as bait. Many crab bait collectors therefore concentrates on peeler crabs of all species, but particularly the very common shore crab Carcinus maenus.

A large family, with seventeen species recorded from Britain (Hayward et al. 1995). The largest of these are commonly collected for human consumption from the shore elsewhere in Europe, but only rarely in the UK (although commercially fished from the sublittoral for export). They may be used for bait along with other crabs. The largest species and those most commonly found in the intertidal are:

Hyas araneus (Linnaeus). Great spider crab. Found in rocky and sandy habitats from the bottom of the shore to depths of 50 m or more all around the UK coasts (where it is common) and elsewhere on the east and west North Atlantic coasts from the English Channel in the south to Spitzbergen, Iceland and Greenland in the North. Reaches a carapace length of 105 mm and width of 83 mm (for large males).

Hyas coarctatus Leach. A slightly smaller species (carapace length 61 mm, width 44 mm) with a similar northern distribution, reaching its southern limits in Brittany. Also common on all rocky and sandy British coasts from the lower shore to 50 m or more.

Maja squinado (Herbst). Common spider crab. Very large crab, often covered with attached algae, reaching a carapace length of 200 mm, width 150 mm. Found on various substrata from the bottom of the shore to about 50 m; abundant in the west and south-west coasts of Britain, but less common in the North Sea. Occurs as far south as Cape Verde and in the Mediterranean.

Corystes cassivelaunus (Pennant). Masked crab. The only species found in British waters, burrowing into sandy soft bottoms from the bottom of the shore to 90 m. Common on all British coasts, and its range extends from Sweden to Portugal and the Mediterranean. May be dug up by bait diggers and used opportunistically for bait.

Cancer pagurus Linnaeus. Edible crab. Found on the shore (from the mid tide level) and in shallow water in Britain, and of significant commercial importance in fisheries. Occurs on all coasts in rocky habitats, from North Norway to West Africa and the Mediterranean. Reaches up to 92 mm in length and 150 mm in width. Large specimens are taken for human consumption, and small crabs, particularly peelers (highly valued as a bait for bass), for bait. There is a minimum landing size for this species, which varies in different parts of the country. Crabs collected for fishing bait from the shore will normally be much less than the legal minimum size, and therefore illegal.

Necora puber (Linnaeus). Velvet fiddler or velvet swimming crab. (Synonyms: Liocarcinus puber and Macropippus puber.) Carapace length to 65 mm, width 66 mm. Blue carapace covered with brown hairs and distinctive red eyes. Very aggressive. Occurs in stony and rocky habitats in the intertidal and shallow sublittoral. Widespread and very common all around the British Isles and occurs elsewhere from West Norway to West Africa and in the Mediterranean and Black Sea. Important for human consumption in many parts of Europe, and recently fished (with pots) in the UK to supply overseas markets. Now beginning to be used as food in the UK, but more likely to be collected for bait during searches for peeling shore crabs. [Any minimum landing size anywhere?]

Liocarcinus depurator (Linnaeus). Harbour crab. Reaches a carapace length of about 40 mm and width of some 51 mm. Very common on soft, sandy and mixed sediments from the lower shore and into deep water all around the British coast. Occurs elsewhere from Norway to West Africa and the Mediterranean. Large enough to be taken opportunistically for bait (or indeed for human consumption) by individuals in search of shore crabs or other bait species. The smaller L. marmoreus, marbled crab, occurs in fairly similar sand and gravel habitats and may also be collected.

Carcinus maenas (Linnaeus). Shore crab, green crab. Attains a carapace length of 60 mm and width of 73 mm. Extremely common and ubiquitous in all intertidal habitats in the British Isles, from splash pools at the top of rocky shores, to saltmarsh ponds, and in estuaries. Also found in the sublittoral. Occurs on most North Atlantic coasts from Iceland to West Africa, and in the north-east Americas, and also in the Indo-Pacific. Widely collected for human consumption in many parts of Europe, and possibly increasingly so in areas of the British Isles. However, mainly used for fishing bait collection (particularly as peeler crabs – see above), and very widely collected, often for re-release, by ‘crabbing’ or ‘rock-pooling’ children. Despite the abundance of this species, particularly intensive gathering for bait can deplete populations locally, and no minimum landing size applies. The main problems associated with intertidal crab collection, however, are habitat damage caused by individuals turning over boulders in search of crabs and not replacing them, and the huge recent increase in the introduction of crab shelters in south-western estuaries. These crabs are a very valuable product, being worth some 40-50p each in summer and 80p to £1 in winter when supplies are very low and demand at its highest.

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