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These crabs inhabit the local shoreline Pagurus bernhardus year Pagurus prideaux round.

Class: Malacotraca

Order: Decapoda Family: Paguridae Genus: Pagurus Pagurus bernhardus

Distribution The hermit crab is a small Hermit crabs in the families Paguridae and Diogenidae are all crustacean found in ocean aquatic marine crabs. The family Paguridae on its own contains waters worldwide. Many several hundred different species. This species P. bernhardus is species are known from known to occur from Spitsbergen, Iceland and the Murman Sea only one or a few localities, throughout the boreal North American and European coasts and many are known world and in the Mediterranean Sea. It is common in Nova Scotian wide. New species are coastal waters. This is one of two known species occurring occurring. locally at Burntcoat Head. The other species is P. prideaux. It is similar in appearance and has somewhat the same distribution. Habitat They live along coasts in Although hermit crabs do venture into deeper waters, they are most types of sea beds, more commonly found in coastal waters where there is more including rocky and shell food and places to hide. Smaller individuals live in shallower bottoms, in sea grass beds, waters than larger individuals. A few species are land based. and sandy or silty Female terrestrial hermit crabs must return to the sea to breed. sediments, but excluding Larvae live mainly in pools and may be found under objects muddy bottoms. such as rocks and seaweed. . Food It consumes microscopic bivalves, scraps of dead animals, The hermit crab is an microbes, and detritus. They are also able to filter organic omnivorous scavenger, particles from the water and will even graze on periphyton (a feeding on a wide variety of type of algae). plant and animal matter.

Reproduction This is followed by a period where both male and female tap Before copulation, a male each other with their chelipods. The female also palpates the pulls a female around by male's mouthparts. When a female is ready to mate, she gives her shell opening, using his either a tactile or chemical signal, causing a male to turn her minor chelipod. He holds around to face him. Individuals must partially emerge from the her by one of her right protection of their gastropod shells and press their ventral walking legs, pulling her surfaces together to allow copulation. Shallow water breeding towards him and tapping season is in general January to February. In deeper waters, where her appendages with his seasons are not very distinct, females can be found carrying eggs major chelipod. throughout the year.

Development The young develop in stages, with the first two occurring inside Females extrude eggs into the egg. Most hermit crab larvae hatch at the third stage, the their shells, gather them via zoea. In this larval stage, the crab has several long spines, a long, the pleopods, and then narrow abdomen, and large fringed antennae. Several zoeal brood them in a manner moults are followed by the final larval stage, the megalopa. similar to other crabs. The larvae may remain with their mother for a number of weeks They will carry around the after hatching before becoming independent and venturing off fertilized eggs (which are into the ocean on their own. Sexual maturity for the larvae is attached to the abdominal often reached before they are 1 year old. Juvenile hermit crabs legs) for up to 2 months are common on rocky shores in all months of the year. before they hatch. The first pair of walking legs (known as chelae) has large forceps Characteristics or claws, the right one being larger; those of the males are larger This species has a carapace than the females. They have a hard, rough, granular surface like of up to 4.0 cm long and a the two following pairs of walking legs while the remaining two maximum body length of 8 pairs are greatly reduced. They are used to hold the shell in cm. The colour is reddish place and to circulate breathing water. They have four antennae. or brownish. The body is The two body segments are the cephalothorax and abdomen. divided into two segments. The cephalothorax is encased by a carapace consisting of three There are five pairs of legs. thick cuticle layers. The abdomen is soft and coiled to the right The two compound eyes Family: Paguridae are the right clawed hermit crabs. are on movable stalks. Family: Diogenidae are the left clawed hermit crabs.

Adaptations The size of the shell is important, it affects the fitness of the These crabs inhabit the hermit crab, a shell that is too large does not offer the best abandoned shells of protection and a shell that is too small restricts its growth. animals, such as periwinkles Individuals may attack each other in attempts to claim and whelks, using them as ownership of a shell. Chelae are used for gathering food and for protection for their soft protection. The larger of the two claws (chelae) is used in bodies. Shells are held in fighting and defence. place by the last two pairs Pagurus prideaux, a second species occurring at of reduced legs. If disturbed Burntcoat Head, is similar in appearance to it retreats deeper into the Pagurus bernhardus but is smaller and redder. shell and barricades the In warmer waters it is well known for its shell’s opening with the symbiotic relationship with a species of sea walking legs, especially with anemone, Adamsia palliata. Young crabs of this the right forceps. species catch young cloak anemones and carry them on their backs. The anemone expands as Status/Threats the crab grows. The close cooperation between Pagurus prideaux These are under no threat. these two animals involves protection and food Potential ocean acidification supply. If the hermit crab feels threatened in any way, it uses is a threat to all marine chemical or mechanical signals to get the anemone to spread out species. They are preyed its long pink tentacles. In return the anemone gets to eat the upon by gulls, fish, starfish, remains from the hermit crab's meals. Young hermit crabs catch octopus and other crabs. young cloak anemones. They grow up together and rarely switch They are vulnerable when partners. In colder waters, this role is filled by Hormathia digitata molting and changing shells a cold water anemone.

Sightings in Nova Scotia These are easily seen along the shoreline of Burntcoat Head.