Sea creatures great and small

Our marine highlights from 2020 offer a fascinating glimpse into the diversity of wildlife found in the Irish Sea and on the Cumbrian coast
Image of first seal pup at South Walney Nature Reserve 5 Oct 2020 © Cumbria Wildlife Trust

The first of five seal pups recorded at South Walney Nature Reserve in 2020 © Cumbria Wildlife Trust 

From majestic whales to tiny ‘sea gooseberries’ and the curious sunfish, people have reported some intriguing sea wildlife while they’ve been out and about on the Cumbrian coast this year. While some of these sightings suggest healthy marine conditions, others may indicate more worrying environmental problems.

Probably the strangest-looking creature was seen by Heather Crompton in May. She told us: “I was sea-kayaking off St Bees when I saw a sunfish, in close proximity, for about 5 mins, about 500m off South Head. My first clue was seeing two of the fins, out of the water, so I paddled over, and it wallowed about near the surface before gently disappearing.”

The ocean sunfish is an odd looking fish. It is huge, flat and circular - looking pretty much like a giant swimming head! The second largest bony fish on the planet, it can grow to a whopping 2m in length! Instead of a tail, it has a stiff fringe of skin (called a clavus), which it can move to act like a ship's rudder. It also has two small pectoral fins and an elongated dorsal fin and anal fin that look a bit like wings.

Although there aren’t many sunfish sightings off the coast of Cumbria, recent research has shown that they are found in the Irish Sea all year round. They mostly feed on jellyfish and may play an important role in controlling large jellyfish blooms. Their presence indicates nutrient-rich waters, good plankton blooms and conditions for jellyfish that then attract the sunfish, as well as other species like leatherback turtles.

Dr Emily Baxter, Senior  Marine Conservation Officer for Cumbria Wildlife Trust said: “We always enjoy receiving people’s sightings of the weird and wonderful wildlife that they encounter on the coast. This sighting was reported to us during lockdown. It was nice to hear how people were able to get out and connect with nature.  But receiving such a rare sighting like this is even more exciting! Heather’s story, along with the photos and video she sent us, really brought the sighting to life and we all wished we had been there to see it!”

Image of sunfish off St Bees Cumbria © Heather Crompton

Sunfish off St Bees, Cumbria © Heather Crompton 

The largest marine sighting of 2020 was of a northern bottlenose whale that sadly washed up near Roosebeck in September. It’s likely that it had become disorientated or trapped in shallow water and assumed that it had separated from the other members of the pod.

Dr Baxter said: “Although it is extremely sad to see such a magnificent creature washed up on the beach, it is a great reminder of the amazing marine life and ocean giants that grace our seas. Northern bottlenose whales are no longer hunted on as large a scale but like other deep-diving, beaked whales, they are thought to be negatively affected by loud man-made noises, and increased strandings in recent years may well be related to human activities. Like other whales and dolphins, they are also at risk of ingesting plastic and entanglement in fishing gear.”

Northern bottlenose whales usually live in the open seas feeding up to 2000m deep. They are easily recognised by their large foreheads, which are particularly pronounced in older males.  The males can grow up to 11m in length, weighing in at over 7000kg.

From the majestic to the minute, in May and June there were several reports of huge numbers of squid eggs washing up on beaches in the North West, after strong winds. Their strange appearance intrigued many people who saw them and wondered what they were. Dr Baxter explains: The jelly-like masses look a bit like a string mop head and most people assume that they are a jellyfish. On closer inspection, a honeycomb-like pattern can be seen within and these are the individual eggs, sometimes it is even possible to see tiny squid! Whilst it is good that squid are here, it’s not good that egg masses get washed up in storm events (which could increase due to climate change) before hatching. However, it’s likely to only be a small percentage of the eggs laid that get washed up.”

Image of squid eggs off St Bees © Natalie O'Kane

Squid eggs off St Bees © Natalie O'Kane

At around the same time as the sightings of masses of squid eggs, thousands of small oval or round, jelly-like blobs, known as sea gooseberries, washed up on the beach from St Bees down to Blackpool. Marine wildlife-watchers had never seen so many washed up here before! They are not true jellyfish but ctenophores, and also known as comb jellies.

Dr Baxter said: “We often get reports (or find them ourselves when out surveying) of the occasional sea gooseberry but we’ve never seen them washed up or in the water in such great quantities! They most likely ended up on the beach due to strong winds. Everyone’s first question is ‘Do they sting?’! The simple answer is no! These delicate, jelly-like creatures are not actually true jellyfish, so they do not have stinging cells.”

While they don’t sting, sea gooseberries are voracious predators, eating up to 10 times their own body-weight a day, including other sea gooseberries! They grow up to 2.5cm long and although they have two long, feathery tentacles, they use a sticky substance rather than sting to catch their prey.

On the other hand, the Portuguese man o’ war definitely does have a nasty sting and one was spotted in Cumbria this summer by Neil and Carol Cockbain. It had washed up on the shore at Beckfoot, near Allonby. Despite appearances, these weird and wonderful creatures are not in fact jellyfish; rather they are a “colonial species” made up of lots of different co-dependent organisms called zooids, each performing a specific role such as feeding or breeding.   

Portuguese man o’ war live in the open ocean, drifting along with their sail-like bladder keeping them afloat at the surface, and putting them at the mercy of the winds! They aren’t commonly found in UK seas, but can be seen washed up here after big storms.

Image of Portuguese Man o' War near Allonby © Neil and Carol Cockbain

Portuguese Man o' War near Allonby © Neil and Carol Cockbain 

Finally, no round up of our marine wildlife would be complete without a mention of the grey seal pups at South Walney Nature Reserve. Five pups were recorded here during the recent breeding season (October-November) and on one occasion this year, a total of 412 grey seals were counted. The recorded population at South Walney has increased dramatically, from only a couple of seals seen using the nature reserve in 1980s and the first pups born in 2015. Grey seals are amongst the rarest seals in the world, with the UK a critically important location for them - 40% of all grey seals on the planet live in the here.

Dr Baxter said: “If the UK had an animal mascot it should be the seal. The grey seal prefers our coasts to anywhere else on the planet. It’s fantastic to see this large marine mammal making a comeback of sorts. It may not be back to its historic population size, but it’s a start and it demonstrates what legal protection, education and conservation efforts can achieve.

“However, we have had some horrendous disturbance incidents this year with people innocently kayaking or walking on the beach near the seals and nesting birds causing real alarm – as well as multiple incidents of people flying drones over the seals. People need to realise that this badly upsets and disturbs vulnerable wildlife.”

Image of seal pup at South Walney Nature Reserve © Cumbria Wildlife Trust

Seal pup at South Walney Nature Reserve © Cumbria Wildlife Trust