Saltwater Crustaceans

Barnacle (Acorn)

admin — Mon, 10 Sep 2007 16:20:35 +0000

Acorn Barnacles are cone-shaped marine crustaceans that can be found along most of the rocky coasts of England at low tide. They can be seen clinging onto rocks and other hard surfaces such as on the underside of boats.

The Acorn Barnacle usually grows to a maximum of one and half centimetres and it has the name ‘Acorn’ because of its cone-shaped shell. The shell is usually an off-white colour and is made up of six plates which surround and protect the barnacle’s body. The Acorn Barnacle opens its shell when the tide is in and then extends six legs out of the shell. The legs are quite small and feathery and are used to filter water to help the Acorn Barnacle to find food particles. It closes the shell when the tide goes out to stop itself from drying out.

Acorn Barnacles are ‘hermaphrodite’ which means they are both male and female. They carry their eggs in special cavities within their shells for about five months. When the larvae hatch out of the eggs, they swim freely in the sea and become part of zooplankton until they grow bigger and can attach themselves to objects.

Barnacle (Goose)

admin — Mon, 10 Sep 2007 16:21:16 +0000

The Goose Barnacle is a marine crustacean with a white heart-shaped shell. It can be found on the west coasts of England and is often found washed up on our shores attached to floating objects. This crustacean attaches itself onto rocks and other hard objects such as driftwood, logs and even thick ropes.

The shell of the Goose Barnacle is about four and half centimetres long and covers most of the barnacle’s body, apart from the ‘peduncle’. The peduncle is a stalk-like part of the barnacle’s body that extends out of the shell and contains some of the Goose Barnacle’s head. The peduncle is a purplish red colour and is approximately four to nine centimetres long. The Goose Barnacle uses its peduncle to attach itself onto objects. This barnacle also has feathery limb-looking organs attached to the front part of the shell. It uses these organs to catch food.

Goose Barnacles are ‘hermaphrodite’ which means they are both male and female. They carry their eggs in special cavities within their shells for about five months. When the larvae hatch out of the eggs, they swim freely in the sea and become part of zooplankton until they grow bigger and can attach themselves to objects.

Crab (Common Hermit)

admin — Mon, 10 Sep 2007 16:21:43 +0000

The Common Hermit Crab is also known as the ‘soldier crab’ and can be found all around the coastlines of England on the shore or in shallow water. It is quite a small reddish-brown coloured crab that carries a shell around with it. It uses the shell as its home. The shell is usually an empty whelk shell and if the Common Hermit Crab sees a bigger whelk shell, it will discard the old one and replace it for a bigger one.

The Common Hermit Crab usually grows to a length of about three and a half centimetres. It has ten pairs of walking legs with two large pincers on the first pair of legs. The right hand pincer is usually bigger than the left-hand pincer because this crab uses it right-hand pincer more. The Common Hermit Crab can shed a leg or a claw when it feels threatened and this is why small parts of this crab can often be found on our beaches.

The Common Hermit Crab has a special relationship with the Sea Orange Sponge because it allows this sponge to grow on its back and sometimes the sponge even becomes a replacement shell for the Common Hermit Crab.

Crab (Common Shore)

admin — Mon, 10 Sep 2007 16:22:11 +0000

The Common Shore Crab is also known as the Green Shore Crab and the European Green Crab. It can be found all around the English coast in rock pools under large stones and amongst bunches of seaweed. It can also be found in estuaries and it is well-adapted to living in diluted seawater.

The adult Common Shore Crab has a body width of around eight centimetres and is usually a dark yellowy green colour. Younger crabs can be yellow, green or red with whitish markings. This crab has ten walking legs with two large pincers on the first pair and its right-handed pincer is bigger than the left. It also has two pairs of antennae of which one pair is quite long.

The female Common Shore Crab carries her eggs under her abdomen where they are attached to tiny legs called ‘swimmerets’. She carries the eggs around with her for several months until they are ready to hatch. When the larvae hatch out, they become part of zooplankton for a while before they move to the shore to develop into mature crabs.

Crab (Edible)

admin — Mon, 10 Sep 2007 16:22:37 +0000

The Edible Crab is a powerful-looking crab and is the largest of our native crab species. It can be found in rock pools all around the English coastline. It can also be found in muddy sand in waters as deep as a hundred metres. This crab is quite a slow-moving crab and because of its size and slowness it often buries itself in the sand to escape danger.

The Edible Crab has a body that is approximately fifteen centimetres wide and can easily be recognised because of its overall reddish-brown colour and its broad shell which looks like it has a pie-crust edge to it. It has ten walking legs with two very large pincers on the first pair. The two front pincers have a black tip and the pincers of the male are generally bigger than the female’s.

The female Edible Crab carries her eggs under her abdomen where they are attached to tiny legs called ‘swimmerets’. She carries her eggs around with her for seven to eight months until they are ready to hatch. When the larvae hatch out of the eggs, they become part of zooplankton for about a month before they move to the shore to develop into mature crabs.

Crab (Leach's Spider)

admin — Mon, 10 Sep 2007 16:23:02 +0000

The Leach’s Spider Crab is a small long-legged crab that can be found all around the coasts of England on sandy seabeds in shallow and deeper waters, although it is usually found about five to ten metres below tide level. It is a very slow-moving crab that is well-skilled in camouflaging itself.

The Leach’s Spider Crab grows to a length of about three centimetres and it can easily be recognised because its long spindly legs and the top part of its body are covered in tiny hook-like hairs. These hairs usually have sea sponge or algae attached to them. Its body is generally a red-brown colour, but this base colour is not so easily seen because of the algae and sea sponge that is attached to its body. Like other crabs, the Leach Spider’s Crab has ten walking legs with two large pincers on the first pair. This crab often folds its pincers under its body.

The Leach’s Spider Crab has a special relationship with the Snakelocks Anemone which is a sea-creature that has long stinging snake-like tentacles. The Leach’s Spider often hides around the base of this anemone and it even sits within its tentacles to camouflage and protect itself.

Crab (Velvet Swimming)

admin — Mon, 10 Sep 2007 16:23:29 +0000

The Velvet Swimming Crab is a common and very widespread crab that can be found all around the English coast. It is also known as the Devil Crab or the Witch Crab because it has bright red eyes and because it can be quite aggressive. Smaller Velvet Swimming Crabs can be found hiding in crevices in shallow water and in rock pools and larger crabs can be found in waters as deep as eighty metres.

The Velvet Swimming Crab has a flat-shelled body which is a blue colour on top. However, most of the blue is hidden by short red-brown hairs which give the shell a velvety appearance and this is why it has its name the ‘Velvet Swimming Crab’. It has ten pairs of walking legs with the rear legs being flattened to help it to swim fast. It also has two large pincers on the first pair of legs which are also covered in fine velvety red-brown hair.

The female Velvet Swimming Crab lays orange coloured eggs which she carries on her underside until they are ready to hatch. The larvae hatch out around spring time and become part of zooplankton for a while before they settle on the seabed to develop into adult Velvet Swimming Crabs.

Lobster (Common)

admin — Mon, 10 Sep 2007 16:24:12 +0000

The Common Lobster is also known as the European Lobster and can be found along the south, south-west and north-east coasts of England. It is quite a large lobster that has a dark blue shell with yellow spots and a yellow-toned underside.

The Common Lobster can reach a length of up to one metre and it can easily be recognised by its two long front walking legs which have two large dangerous-looking pincers at the tip. One pincer is used for crushing prey and the other pincer is used for cutting it. The Common Lobster has eight other walking legs and two pairs of antennae of which one pair is very long and thin. The head and body is covered in a shell and the abdomen is flexible because it has no shell covering. This lobster, like the Norway Lobster, has a broad fin-like tail.

The female Common Lobster carries her eggs on the underside of her abdomen until they are ready to hatch. The larvae hatch out of the eggs around April to May and live amongst zooplankton for a while before they settle on the seabed to develop. Most fishermen return egg-bearing females into the water to help preserve lobster numbers.

Lobster (Norway)

admin — Mon, 10 Sep 2007 16:24:37 +0000

The Norway Lobster is a small orange-pink lobster that can be found all around the rockier coastlines of England. It is also known as the Dublin Bay Prawn and the tail of this lobster is often referred to as ‘scampi’ which is a popular sea food dish.

The Norway Lobster is about fifteen centimetres in length and it can easily be recognised by its two long clawed legs at the front of its body and by its large black protruding eyes. It has eight other legs and two pairs of antennae of which one pair is very long and thin. The head and the body of the Norway Lobster are covered in a shell, but the abdomen has no shell covering and is very flexible. This lobster, like the Common Lobster, has a broad fin-like tail.

The female Norway Lobster carries her eggs on the underside of her abdomen until they are ready to hatch. The larvae hatch out of the eggs around April and May and live amongst zooplankton for a while before they settle on the seabed to develop into adults. Most fishermen return egg-bearing females into the water to help preserve lobster numbers.

Prawn (Common)

admin — Mon, 10 Sep 2007 16:25:02 +0000

The Common Prawn is also known as the Pink Shrimp. It is a crustacean like the Common Lobster, the Common Crab and the Common Shrimp. It can be seen all around the coasts of England in shallow waters amongst seaweed and in rock crevices. It can also be found in rock pools and estuaries.

The Common Prawn is about eleven centimetres in length and has an almost transparent pinky brown coloured body. Its head and body is covered with a thin pinky brown shell which is covered in red or brown lines and markings. The shell extends outwards in front of the prawn’s eyes and curves upwards. This extended shell is called the ‘rostrum’. The Common Prawn has five pairs of walking legs which are yellow or brown. The first and second pair of walking legs have pincers to help the prawn to grab food. It also has two pairs of antennae. One pair is very short while one pair is very long and trails backwards in the water.

The female Common Prawn carries her eggs on the underside of her abdomen for about four months until they are ready to hatch. The larvae hatch out of the eggs around April to June and live amongst zooplankton for a while before they settle on the seabed to develop into adult Common Prawns.

Shrimp (Common)

admin — Mon, 10 Sep 2007 16:25:30 +0000

The Common Shrimp is also known as the Brown Shrimp because it is mainly brown in colour with tiny darker brown spots. It can be found all around the English coast on sandy and muddy seabeds and occasionally in estuaries. It is quite difficult to detect because it likes to bury itself into the ground with only its eyes and antennae showing above the surface.

The Common Shrimp is usually about five centimetres long, but it can reach a length of up to nine centimetres. It has a flattened head and body. The body is covered in a shell that extends to a point between the eyes. It also has long whip-like antennae at the front of its head and two black eyes that are on stalks. It has five pairs of walking legs of which the first pair has two large pincers to catch and cut prey. The abdomen of this shrimp tapers at the end and is flexible because it has no shell covering. The Common Shrimp also has a broad fan-like tail which it quickly contracts when it wants to swim backwards.

The female Common Shrimp carries her eggs on the underside of her abdomen until they are ready to hatch. The larvae hatch out of the eggs in early spring and summer and become part of zooplankton for around four weeks before they settle on the seabed to develop into adult Common Shrimps.