Our marine secrets

In water our senses our severely hindered; so it’s tough for us to get interested in the plants and animals which lurk beneath the

waters of our seas. Grey waters at that; cold waters too; and often pretty rough. Yes, the UK’s seas are in sore need a public relations makeover. And they more than deserve it as they are crammed with astonishing wildlife. Scientists believe that as many as half of all the species which inhabit the UK live in and around the sea. So for every

blue tit visiting your feeder, for every dandelion you see in flower, there’s another species living in the sea. And each of these marine species is leading a remarkable life: coping with currents and tides; withstanding tremendous water pressure; migrating up and down the water column; living at times as planktonic larvae and later as fixed adults; dodging predators, including humans; colonising the feet of offshore wind-farms. Sea creatures do all of this, and far more, every day.

DISCOVEROUR MARINESECRETS

This summer let’s keep marine wildlife, though out of sight perhaps, firmly in our minds. Let’s get out during National Marine Week and learn about seaside wildlife and its habitats; let’s think about marine conservation; above all, let’s fall giddily in love with lobsters, limpets and sea lettuce. For the first time in our lives, let’s really see the sea.


10MARINESECRETS

In primary school we learn that every ecosystem starts with a plant – a producer – and that plants are green because they photosynthesise using chlorophyll. So why are many marine algae pink or red? These plants, including encrusting red algae, can survive and photosynthesise in very low light levels, where most wavelengths have been filtered out by the seawater. To do so they must employ other light-catching pigments and it’s these that give them their gorgeous colour. Like many sea species encrusting red algae don’t look at all how we would expect and have much more the look of a coral than a plant.

There are plenty of snails in the sea, all doing fascinating things. Dogwhelks drill holes in the shells of their prey with their tongues; common whelks produce great frothy balls of eggs; painted topshells are palette-challengingly beautiful. But let’s spare a thought for the humble, ubiquitous common winkle. Found on every UK coast, especially in rocky areas, the common winkle is omnivorous but specialises in scraping algae from rocks with its rough tongue known as a radula. Like many sea-snails it has an operculum, a trapdoor with which to close its shell when the tide is low and the exposed winkle is at risk of death by dehydration.

Encrusting red algae Common periwinkle1 2

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10MARINESECRETS

We all know that swallows and swifts migrate but did you know that the eyes of flatfish, including the common sole, also migrate? The common sole is a right-sided flatfish, meaning that both of its eyes are on its right side while it lies on its left side on the sand or mud of the seabed. The newly hatched sole, however, is fish-shaped with one eye on either side of its face. Amazingly, as the little fish grows, its left eye migrates to the right side of its body and the whole fish tilts to make its right side its upper surface. Common soles are found on soft seabeds all around the UK.

Among the commonest finds in the strandline in the UK are what look like brittle bits of beige seaweed. These are in fact hornwracks: colonies of minute filtering animals known correctly as bryozoa (pictured above). Many species of bryozoa inhabit the UK, with a bewildering variety of forms, but hornwrack and the weird jelly-like finger bryozoa are some of the most likely to be seen stranded at the top of the tide.

Common sole Bryozoa3 4

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10MARINESECRETS

Thanks to the tides, mudflats and saltmarshes spend part of their time as land and part underwater. Both habitats are built by the tide when, just at the point when it turns, it drops the finest silt sediments. These are colonised by a host of plant and animal species. Late summer is undoubtedly the time to visit a saltmarsh for its plants as now the whole marsh is lit with the mauve of common sea lavender and the brilliant gold of sea aster, all contrasting with the silvery leaves of sea purslane. These plants are easy, so set yourself a challenge to find the subtlest saltmarsh flowers. At the upper edge of the marsh look for the tiny blooms of lesser sea-spurrey, and congratulate yourself on seeing the even tinier differences which separate it from greater sea-spurrey!

The eel’s name does it a grave injustice. It would be fairer to call it the Atlantic-crossing eel, for this is a fish which, during its lifetime, crosses the Atlantic twice. Spawned off the southeast coast of North America the young eels drift as plankton to Europe and develop into minuscule eels as they reach our rivers. These tiny, transparent fish swim upriver and, if they are lucky, may spend years fattening up as freshwater fish before swimming back across the Atlantic to breed. Catastrophic declines in recent years mean the European eel is now listed as critically endangered.

Lesser sea-spurrey European eel5 6

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10MARINESECRETS

A relative of albatrosses, the fulmar is easily overlooked. Gull-like at a superficial glance, the grey and white fulmar flies on stiffer wings and, especially in high winds, banks dramatically from side to side. It is a cliff-nester and, though capable of wandering thousands of miles over the open ocean, is easily seen around its colonies year-round. Around 500,000 pairs of this graceful bird nest in the UK, an astonishing fact considering that, with the exception of a colony on St Kilda, the fulmar first nested here – in Shetland – in 1878. Its rapid colonisation of much of the UK was possibly related to the expansion of industrial fishing, the scraps from which proved perfect food for this resourceful bird.

The sea is stuffed with crustaceans – lobsters, crabs, prawns – but among the humblest is the brown shrimp. Found on soft seabeds all around the UK, the brown shrimp feeds at night and spends the day buried in sand or mud with only its eyes and antennae exposed. A predator, the brown shrimp will also ambush its small animal prey from this hiding place in the sand. The shrimp in turn is important prey for many fish and seabirds, and in some regions for people.

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10MARINESECRETS

Everyone is familiar with starfish, at least by name, but how many of us know about brittlestars? These are the elegant, strap-legged relatives of starfish which – in a glorious range of colours from gold to violet - inhabit hard-bottomed shores around the UK. Unlike the starfish, which is a predator of mussels, the brittlestar is a detritivore, one of nature’s recyclers. Like many marine animals, its larvae initially float as plankton through the sea before developing into tiny brittlestars and setting up home on the seabed.

Whales are vast and impressive; dolphins are charismatic and playful. Porpoises, on the other hand are the UK’s most widespread and readily-seen cetacean. Found close to shore around almost all UK coasts, at just 1.5m the little porpoise is the smallest cetacean in the North Atlantic and one of the smallest in the world. Seeing a porpoise requires patience and concentration as they are undemonstrative at the water’s surface. Find out where they are regularly being seen, choose a very calm day, sit on raised ground such as a headland and wait to glimpse the rounded back and small triangular fin which identify the harbour porpoise.

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Our marine secrets

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