Local Marine Biology

Photo credit Copyright Rob Spray, Seasearch East 2021

The coast of Norfolk provides a rich and varied habitat. Both above and below, and sometimes happy in either position, there is so much wildlife to be found on our beaches and in the North Sea. Seaweeds of many shades of red and green are the foundation of Read on to discover more about the different regions and what can be found there.

Life beneath the waves

The chalk reef is an amazing place to visit, the wildlife doesn’t all run away.

Photo credit Copyright Rob Spray, Seasearch East 2021

The marine wildlife of Norfolk is amazingly varied, including huge shoals of flashing, silvery fish, big fat anemones in rippled ice cream colours, angry cuttlefish the size of bumblebees, waving meadows of green, brown and red seaweeds, tiny delicate spider crabs and bright patchworks of sponges splashed across the rocks.

Photo credit Copyright Rob Spray, Seasearch East 2021

Animals and seaweeds occupy every space they can.

This impressive variety is made possible by the unique range of habitats that are found just off the coast. As well as the famous chalk reef with its 3m high gullies full of tunnels and caves, there are smaller reefs of wood, peat and clay, narrow carstone and wide flint boulder fields covered in a turf of hydroids and bryozoans, plains of gravel and pebbles full of clams, and fine sand with dense beds of razor shells and sandmason worms. Even upright metal shipwrecks sitting high above the seabed can be home to a diverse community of animals and plants, allowing them to reach the strongest, feeding currents. All these habitats suffer from human pressures we can’t see from the surface – but which we can work to reduce.

Abandoned fishing gear damages these fragile habitats

Photo credit Copyright Rob Spray, Seasearch East 2021

We have a unique mix of wildlife here because the sea has a very large temperature range, typically from 4°C in February to an occasional 22°C in August. Our water is also very turbid (a nice word for murky) at times too, meaning that very little light gets through between November and June. These challenges mean that the animals and plants in the North Sea have to be very tough and adaptable to survive. Many of the seaweeds and colonial animals act like herbaceous perennial plants, dying back to a small stable core in the winter, then expanding out again as the water clears in spring. Other animals such as lobsters move out into deeper water, or become inactive when the water is very cold. Resident fish just try to carry on as usual, which can make them vulnerable to storm events, whereas others move around the coast following food.

Corkwing wrasse are one of the most colourful fish in British waters, and a Norfolk resident

Photo credit Copyright Rob Spray, Seasearch East 2021

Marine life can be a bit difficult to understand, most is very different to the animals and plants seen on land. Few land animals wait around hopefully for food to fall into their mouths from the sky, but that’s a very popular way of life under the sea!

Rockpools – life in the inter-tidal zone

a juvenile edible crab (Cancer pagarus) Elizabeth Beston

The rockpools at West Runton are an intertidal part of the North Norfolk chalk reef. The MCZ boundary starts 200 m from the coastline, so the rockpools are adjacent to it, rather than part of it (The Wildlife Trust, 2020). The rockpools are within the boundary of the West Runton Cliffs Site of Specific Scientific Interest (SSSI) due to their geology (Natural England, 2020).

a stalked jellyfish (Calvadosia campanulata) Elizabeth Beston

The rockpools at West Runton are the only ecosystem of this type found in Norfolk and is thought to have limited biodiversity due to their isolation and size (Norfolk Wildlife Trust, 2020). Despite these limitations, many species of animal and alga can be found here, and it provides a sheltered nursery area for many species, including crabs and fish. A range of other organisms can be found in the rockpools, including starfish, sea anemones, molluscs, sponges, brittle stars, and many types of seaweed.

A common goby (Pomatoschistus microps) Elizabeth Beston

For a more detailed description of West Runton’s rockpools, check out Elizabeth’s website and blog here

Breaking marine life down into groups of similar species can help us to work out how everything fits in.

Seaweeds (Algae)

Photo credit Copyright Rob Spray, Seasearch East 2021

Seaweeds are the foundation of many ecosystems – and they’re beautiful too!

Seaweeds enthusiastically cover shallow, stable ground in summer – because they need light just like surface plants. They’ll even grow through a layer of sand if there is something underneath to cling to. Over 100 different kinds of seaweed have been recorded off Norfolk. Beyond the wracks and sea lettuce you often see at the shore, our most common are two red species called Combweed and Eyelash weed and a brown called Dotted peacock weed.

A rather lovely alien, invasive, red algae called Devil’s tongue weed has recently moved in and become very common, it looks like twisted pink ribbons and is horribly slimy! Seaweed slime is important though, that’s how they shrug off wave action beating them against rocks when storms come through.

Devil’s tongue weed (Grateloupia turuturu) is ruffled, spiralled and always moving in the water.

Photo credit Copyright Rob Spray, Seasearch East 2021

Sponges (Porifera)


Mermaids glove (Haliclona oculata) isn’t your average square bath sponge

This image has an empty alt attribute; its file name is 07-m1ii7260.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Norfolk is home to many varieties of sponge, including our now famous purple, encrusting sponge. That’s new to science and not found anywhere else in the world so far! It’s so ‘new’ that it doesn’t have a proper, scientific name yet, a local competition gave it the common name ‘Parpal dumplin’. Other sponges include Mermaid’s glove, which suggests that mermaids have loads of very thin fingers and Shredded carrot, which can look exactly like the stuff that turns up in salads.

Sponges are very simple animals, made up of cells that can perform any job that turns up. They don’t have any specific organs or tissues and can survive being grazed back to almost bare rock by passing predators. They are also very ‘plastic’, easily moulded into weird shapes by currents, which makes identification very difficult!

Shredded carrot sponge (Amphilectus fucorum) gets tasselled in strong currents

This image has an empty alt attribute; its file name is 08-p8040477.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Jellyfish, corals, anemones and hydroids (Cnidarians)

Jellyfish aren’t all stingers – these Moon jellies (Aurelia aurita) are harmless

This image has an empty alt attribute; its file name is 09-l3093146-002.jpg
OLYMPUS DIGITAL CAMERA

These animals can look quite different from one another but all catch and disable their prey by firing out tiny harpoons. Most just stick to their victims so that they can be pulled in, but others contain strong toxins; some jellyfish stings can be very painful for humans!

We have one soft coral locally, the creepily named Dead man’s fingers, which makes most sense if the deceased was the Michelin man, as the fingers are wide and rubbery! When actively feeding in the summer, this coral is covered in thousands of little, stinging polyps, like tiny anemones, grabbing particles out of the water.

Our anemones include the Dahlia anemone, which is covered in sticky warts on the outside so it can pick up gravel as armour when it closes and the Plumose anemone which has a tall column pumped up with water and topped with a plume of fine tentacles like ostrich feathers.

Dead mens fingers (Alcyonium digitatum) are soft corals

This image has an empty alt attribute; its file name is 10-l3210284.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Dahlia anemones (Urticina felina) are actually the same size as their namesakes.

This image has an empty alt attribute; its file name is 11-m1ii7055.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Marine Worms


Marine worms have the same problem as the garden earthworm, their soft, squashy bodies are delicious! So while some just hide in sand others build themselves armour, which can be very strong or taste really bad! They come in myriad shapes and sizes; from tiny Keelworms making hardened tubes with colourful 5mm feeding fans to Peacock fanworms secure in ‘straws’ of mucus and food waste high on reefs and wrecks topped with 15cm radiating rings of orange and brown.

An alien, invasive worm that doesn’t yet have a common name, called Pileolaria berkleyana has recently arrived off East and West Runton. It’s a spiral tube worm and is rapidly spreading, squeezing out sponges and squirts from their niches on the chalk. The individuals are almost too small to see, but they snap their soft edible bits back into their tubes when startled, making whole boulders seem to flash from orange to white as you pass.

Keelworms (Spirobranchus species) are far from plain close up

This image has an empty alt attribute; its file name is 12-l3210387.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Peacock fanworms (Sabella pavonina) use their radiating tentacles to catch passing food

This image has an empty alt attribute; its file name is 13-sabpavrsnorfolkpb090078-001.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Sea squirts (Tunicates)


Lightbulb sea squirts (Clavelina lepadiformis) may only be 2cm high but they are stunning

This image has an empty alt attribute; its file name is 25-p5174738.jpg
Lightbulb Sea Squirts

Sea squirts are in the same group (phylum) as humans and fish, but have gone for a much simpler lifestyle. As adults they settle down and give up their spinal cord and brain to become an eating and breeding machine. They feed as a simple seawater pump, catching particles on a net of regularly digested and replaced mucus. Some live as individuals, while others are colonial, each with their own mouth but sharing one outlet hole between many grouped individuals.

Beautiful little Lightbulb sea squirts grow as clumps of individuals with glowing bright lines inside a transparent body, looking very much like old fashioned, filament lightbulbs.

Around marinas Yellow ringed sea squirts can often be seen on anything pulled out of the suspiciously nutrient rich water. They’re translucent white with a yellow ring around both of their  holes and will squirt out little jets of water when unhappy.

Yellow ringed sea squirts (Ciona intestinalis) flourish in calm water which is nutrient rich

This image has an empty alt attribute; its file name is 26-l3093103.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Starfish, urchins and relatives (Echinoderms)


Starfish (Asteria rubens) gather wherever there is something to eat – here it’s barnacles

This image has an empty alt attribute; its file name is 22-m5084268.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021



At first glance, the animals in this group don’t seem to have a lot in common, but all have a tough, spiny skin and most move on tube feet powered by water pressure. They also all have radial symmetry – if you look down from above and spin them (don’t!) they’d look the same in many positions.

There are years when Norfolk seems almost overwhelmed by Common starfish which scavenge or predate anything that can’t get away – and are drawn to the smell of carrion. With their 5 stubby arms and rough skin, they’re a familiar sight at the seaside but we also have their more attractive relatives too.

The more elegant Bloody Henry can be combinations of purple, red, orange and yellow, and has 5 smooth tapering arms. A more impressive animal is the 13 armed Common sunstar which is patterned in bright orange and red and grows big enough to eat starfish themselves.

Common sea urchins live in the deeper areas, grazing on hard surfaces with their five big teeth while keeping enemies at bay with sharp spines. Their smaller relative the Green sea urchin is found around The Wash where it feeds on seaweed, and genuinely prefers to wear a hat!

Common Sunstars (Crossaster papossus) are fearsome predators… but not very fast

This image has an empty alt attribute; its file name is 23-p7310771.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Hats really do make the small Green sea urchin (Psammechinus milaris) feel more comfortable

This image has an empty alt attribute; its file name is 24-m5318739.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Crabs, lobsters, prawns, barnacles (Crustaceans)


Divers often meet Common lobsters (Homarus gammarus) patrolling the seabed

This image has an empty alt attribute; its file name is 14-p80405242.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Crustaceans wear hard, jointed skeletons outside and need to replace them when they outgrow them. Their new exoskeleton starts soft and stretchy and gets pumped up with seawater before it hardens, so the growing animal has room to expand. Most of our larger crustaceans, such as Edible crabs and lobsters get much of their nutrition from scavenging carrion, while their smaller relatives, such as porcelain crabs sieve water to collect particles of food.

Sponge spider crabs have a very light shell, so they rely on camouflage. They delicately pick tiny pieces of sponge and attach them to hooks on their shells. The sponges continue to grow and merge to form a brightly coloured sumo suit for the crab, helping it blend into the background. Every moult, the crab carefully transfers sponge over to its new shell, so that it always has the same camouflage.

Skeleton shrimps are tiny predators that look like a cross between a praying mantis and the creature in the Alien films – they live just far enough apart to avoid being eaten by their neighbours and use their folding front legs to spear passing animals, and then suck them dry.

Sponge spider crabs (Inachus species) even collect the Purple Norfolk sponge

This image has an empty alt attribute; its file name is 15-m5052370colour2.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

These tiny Skeleton shrimps (Caprella species) are living on a Mermaids glove sponge.

This image has an empty alt attribute; its file name is 16-rs059346crop.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Sea Mats (Bryozoans)


You have to be very close up to see the individuals in a Sea Mat

This image has an empty alt attribute; its file name is 20-picasabackground-005.jpg



Bryozoans are complex colonial animals that work together to build structures to live in. To feed they extend tiny, clear shuttlecock shaped ‘faces’ into the water to collect particles. They don’t have stings, like some similar looking cnidarians, but some species collectively feed defensive individuals who fend off predators and animals trying to settle on the colony.

There are many living off Norfolk and the most familiar is Hornwrack, the pale beige leafy looking stuff that often washes up on beaches. Although you may have been told that it’s seaweed if you pick some up it feels rough. That’s because the surface is made up of thousands of tiny cells that the colony used to live in, you can see them with a magnifying glass.

Another bryozoan that often washes up on the beach is Finger bryozoan, which builds vaguely finger shaped colonies full of jelly. These often get caught up in fishing nets and the rough surface causes fishermen to get a kind of eczema called ‘Dogger bank itch’.

People think stranded Hornwrack (Flustra foliacea) is a seaweed, but it’s an animal colony

This image has an empty alt attribute; its file name is 21-dw287232-1.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Snails,mussels,octopus (Molluscs)


Blue mussel (Mytilus edulis) beds filter seawater for food, and so can concentrate pollution.

This image has an empty alt attribute; its file name is 17-m5166755.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Molluscs are divided into 3 main groups: bivalves, gastropods and cephalopods.

Bivalves, with two paired shells, are usually filter feeders. Our most important ones are Razor shells that have huge beds in fine sand and Piddocks which bore into soft rock such as chalk and clay. They both rely on hiding to keep them safe from predators. Blue mussels don’t hide, but have very strong shells and use tough strings called byssus threads to bind themselves together and to tie up any slow moving predators that attack the group.

This image has an empty alt attribute; its file name is violet-sea-slug-rs.jpg
Violet sea slug (Edmundsella pedata) Photo credit Copyright Rob Spray

Gastropods include all the snail and slug shaped animals (like the ones in your garden!), such as Limpets, Whelks and Periwinkles. A more exotic branch are the nudibranchs, carnivorous slugs. Our most common nudibranchs are the Violet sea slug which recycles stings from its cnidarian prey for its own defence and the Crystal sea slug which concentrates toxins from bryozoans in the tips of its tentacles to stop fish from taking a bite.

This image has an empty alt attribute; its file name is crystal-sea-slug-rs.jpg
Crystal sea slug (Janolus cristatus) Photo credit Copyright Rob Spray

Cephalopods are super intelligent and include octopus, squid and cuttlefish. Our amazing Little cuttlefish hunt over fine sand and although only the size of a bumblebee, can do everything their larger relatives can, including changing colour, firing ink and injecting venom into prey. They feed on Brown shrimp and fish twice their size, so need to disable them quickly before pulling them into the sand to eat.

This image has an empty alt attribute; its file name is 19-pb056459-001.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Common whelks (Buccinum undatum) rove the seabed, sniffing out prey with their ‘trunk’. They like to feed on a variety of animals; worms, crustaceans and other molluscs and can bore through shells with their sharp mouthparts.

This image has an empty alt attribute; its file name is 18-rs023006.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Fish


Magnificent shoals of  Bib (Trisopterus luscus) swirl around the seabed

This image has an empty alt attribute; its file name is 27-rs259629.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Thornback rays (Raja clavata) are a rare but dramatic sight. Cartilaginous fish breed late in life, and slowly making them vulnerable to fishing.

This image has an empty alt attribute; its file name is 28-p9173252.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

There are few more characterful faces than a Tompot blenny (Parablennius gattorugine)

This image has an empty alt attribute; its file name is 29-p9231122_tompoy_blenny.jpg
Photo credit Copyright Rob Spray, Seasearch East 2021

Birds

This image has an empty alt attribute; its file name is 2016-01-08-cormorant-christchurch-park-ipswich-suffolk_z5a9174.jpg
Cormorant (Phalocrocorax carbo) Photo credit Copyright Carl Chapman

Many seabirds, such as Terns and Herring gulls snatch fish from the water surface, while Gannets, Cormorants and Auks actively hunt beneath the waves.

This image has an empty alt attribute; its file name is 2017-05-28-fulmar-john-o-groats-scotland_z5a8606.jpg
Fulmar (Fulmaris glacialis) Photo credit Copyright Carl Chapman

Full details of all birds to be found in Norfolk including seabirds can be found at the Norfolk Birds website.

Marine Mammals – seals, dolphins and whales

Harbour and Common seals also chase the fish, concentrating on the larger species, such as Bass and Ballan Wrasse. They breed on land, but spend most of their lives in the water, even sleeping on the seabed and occasionally floating up to take a breath!

Grey Seals were rare visitors to Norfolk before the mid 20th century. Now the county holds two internationally important rookeries.

Photo credit Copyright Carl Chapman, Wildcatch Photography 2021

Porpoises, dolphins and whales frequent the seas around Norfolk. Around twenty species of cetacean of the thirty or so that have frequented British waters have occurred here in Norfolk. However, it is not a hotbed for cetaceans; most are incidental. By far the commonest cetacean to occur here is the Harbour Porpoise. Minke Whales and Common Dolphins are the next most commonly seen animals. For a full breakdown of what is and has occurred here visit the Norfolk Cetaceans site.

Minke Whales are more frequent off Norfolk in Autumn as they migrate to more Southerly waters.

Photo credit Copyright Carl Chapman, Wildcatch Photography 2021
Create your website with WordPress.com
Get started