Seaham Dive Survey: marine life near Seaham

Seaham Dive Survey: marine life near Seaham


You may be surprised by the sorts of creatures that can be found in the shallow coastal waters off Seaham. Here we come across an edible crab or pie crab. It is called this because of the strange shape of the shell actually looks like the crust of a pie. Like all crabs it has eight legs and two arms with powerful claws, which it uses to catch food or to fight with. As we move across the seabed we come across a sponge. Sponges are strange animals that can form huge sheets or mounds. They can form odd shapes and have holes in them. They filter feed by straining food particles from the water. This one is called a breadcrumb sponge. The rocky seabed provides holes, nooks and crannies for sea animals to hide under away from predators. Continuing across the rocky reef we come across another pie crab. Perhaps filter feeding – crabs often do this. It is hiding behind some hydroids but upon our approach, it scurries off. A disturbed hermit crab scampers over the rocks where you can see the small, white tube-like shells of worms. These are called Serpulids. A red seaweed holds on to a rock by a stem-like structure called a holdfast. This prevents it being swept away by strong currents. Below the seaweed two common starfish can be seen. The seabed consists of small rocky outcrops and lots of sediments. This is covered in seaweeds, marine debris and sedentary marine animals. This is actually called marine turf. An animal that likes to move among this marine turf is the sea lemon. It is a soft-bodied, oval shape creature. It is actually related to the slugs in your garden. It likes to graze upon sponges, especially the breadcrumb sponge and it can grow up to twelve centimetres in length. Here on this reef you can see large sheets of breadcrumb sponge. Also, amongst this dense marine turf are colonies of hydroids. They have erect, long tubes with many tentacles. They look like a plant but in fact they are an animal. The passing particles of food are caught on the tentacles and then drawn into the mouth of the hydroid. Hiding among this turf is the velvet swimming crab. It is a voracious predator and has very distinctive red eyes. It is called a swimming crab due to the fact its rear legs are wide and paddle shaped. On with our journey we find more nooks and crannies in the rocks where many sea creatures like crabs like to hide. A lobster is startled from its hiding place, only to panic and disturb squid eggs as it hides again. The long white tubes that you can see are a sac containing many eggs. A female squid has secured the egg sacs to the underside of the rock. Eventually the little juveniles will hatch and propel themselves out into deeper water. As we explore further we come across evidence of activity from a lugworm. The worm is probably about twenty centimetres in length. The cast you can see is in fact the left over digested food material. The worm lives in a u-shaped burrow, and is very common on sandy shores. It is an important food item for wading birds, fish and a popular bait for fishermen. Continuing our journey we come across a mussel bed. The mussels are attached to the rocks. This provides a stable structure from where they can catch passing food particles. As you can see, the mussel shells are open, so they are feeding. Unfortunately for the mussels they are preyed upon by the Common Starfish. You may have come across them when rock pooling on the shore. They can be found at all depths in British waters and are fond of eating mussels. They have five arms that are so powerful they can prise a mussel open. The starfish gruesomely ejects its stomach over the mussel that it is going to eat so it can digest it. An anemone attaches itself to stones and shells buried under the sediments. It will secure itself there and then feed using its tentacles that it puts out into strong currents. Anemones can be all sorts of colours, from red, green, orange and brown, and can be either solitary, or form quite dense colonies. They can also live at varying depths of the seabed. A soft coral with the unfortunate name of dead man’s fingers can be seen here. It is very fluffy-looking and can be white or orange. It can form huge colonies that completely cover rocky reefs. A hermit crab dashes over the undulating sandy seabed, disturbing other resting crabs as it goes. Another powerful predator is the lobster. It mainly hunts at night. During the day it lives in a burrow or under a rock. They have a highly adaptive sensory system, and can detect the smallest movements or smell within the water from their surrounding environment. They also have powerful claws – one for crushing and one for cutting up their prey. A diver’s torch highlights a soft coral called a plumose anemone. It has colonised the remains of a shipwreck’s boiler. It is tall and fluffy looking, with a mass of tentacles. The anemones can be white, orange and brown in colour. The boiler provides an ideal structure from which these anemones can settle, and also an ideal habitat for other creatures such as juvenile crabs. As we finish our dive in the shallow waters off the coast of Seaham we have observed that it is inhabited by many different marine creatures that live within the rocky outcrops or the undulating sandy seabed. What a place this would be to live if you could have weather like this all the time. Or at least three days of the year!

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