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Meet the relatives!

Star Ascidian/chwistrell serennog (Botryllus schlosseri) - North Wales Wildlife Trust

They may be distant relatives, but sea squirts are more closely related to us that many other creatures you can find on the shore. Their larval form has something called a notochord, which helps to organise the nervous system and which is present in all Chordates. All animals with backbones (that’s us) are grouped within the larger animal grouping (Phylum) Chordates, together with Tunicates (the squirts) and Cephalochordates (small fish-like invertebrates).

You might not see too much of a family resemblance with your clan, though. UK squirts are small, sometimes completely transparent and stuck permanently to surfaces, from lower down in the intertidal zone and further out into shallow seas to vast depths. They have an outer wall (tunic) called a “test”, which holds in a filtration system (branchial sac), so the seawater which is drawn in through the inhalant, “oral” syphon can be cleaned of nutrients before being ejected through the exhalant, “atrial” syphon. It is through the exhalent syphon some of them may squirt out this water, when disturbed, which gave them their name. Squirts can live as individual animals or as a colony of zooids which share the same outer test. Colonial squirts will often share the atrial syphon with a small group of others within the colony. Colonial squirts can also reproduce asexually as well as sexually which is the only reproductive option available to the unitary form.

For those in the (plant-life) know, you’ll be thrilled to learn that tunicates are the only group of animals able to make their own cellulose-type substance. They use this in their outer test, creating a tough defence. Together with many molluscs and sponges, tunicates provide a filtration service which is vital for our seas. As our closest invertebrate relative, they are also helping to inform scientists about our own health – for instance they have a certain physiology which is helping researchers learn more about our innate gut immunity and since they filter out plastics (of which there is an abundance in our seas) and store them in their test, they can be investigated to see what effect microplastic pollution might be having on other Chordates like us.

Identifying squirts can be tricky, but there are a few which can be fairly easily identifiable so here’s a very quick introduction to those:


Bot Schloss Sophia and Ann Wake

Bot Schloss Sophia and Ann Wake

Star Ascidian/chwistrell serennog (Botryllus schlosseri) – is a colonial sea squirt, whose zooids sit together in small groups, which create shapes likes stars or flowers. Their shared pore is placed in the centre of the colony and the zooids lie attached to the surface, flattened splayed away from the centre longer than wide. They can be a wide variety of colours, often blue-ish, but also green, orange, purple, red and brown. They live attached to rocks and algae, but also sometimes to other ascidians.




Baked bean sea squirt/chwistrell fôr gôch (Dendrodoa grossularia) Lara Howe, Manx WT

Baked bean sea squirt/chwistrell fôr gôch (Dendrodoa grossularia) Lara Howe, Manx WT

Baked bean sea squirt/chwistrell fôr gôch (Dendrodoa grossularia) – although these are classed as unitary squirts they still often form large clusters. They’re unitary in terms of how they grow within that cluster. They can actually exhibit different growth forms, so they don’t always looks bean-like which gives them their English common name. They can grow on rocks, shells or algae and tend to be reds or browns.







Lightbulb sea squirt/chwistrell wydr (Clavelina lepadiformis) - North Wales Wildlife Trust

Lightbulb sea squirt/chwistrell wydr (Clavelina lepadiformis) – North Wales Wildlife Trust

Lightbulb sea squirt/chwistrell wydr (Clavelina lepadiformis) – a delightful find, this sea squirt lives in loose colonies under rocks. They’re clear with a strip of white running along the length and rims of the siphon openings, which makes each zooid look like a glass lightbulb with the filament lit up. The zooids are only attached at the base through a stolon-type system attached to the rock.



Yellow-ringed sea squirt/chwistrell fôr (Ciona intestinalis) - Paul Naylor

Yellow-ringed sea squirt/chwistrell fôr (Ciona intestinalis) – Paul Naylor

Yellow-ringed sea squirt/chwistrell fôr (Ciona intestinalis) – tall with a colourful edge to both siphons, this squirt likes to be sheltered and can often be found attached to jettys, pier and buoys. In areas which are more exposed it is more likely to live on its own, whereas when less exposed to wave action it forms clusters. These animals contract when disturbed.


Fascinating fact: The squirt heart (basically a tube that contracts) is able to reverse its pumping direction every few seconds and has been found to be very similar to the mammalian heart functioning.

Keep an eye out for our Shoresearch surveys to get a better understanding of our intertidal life including our squirts.

Shifting Seasons of the Sea

Autumn’s Arrived, or at least it feels like it anyway

If you have been observing recent seasonal changes on the land that signal the end of the summer and of autumn’s arrival, you might be, like me, surprised that it feels a little early. Leaves of sycamore are turning that beautiful bronze colour, falling and scattering on the ground, flocks of migratory birds are gathering to begin their long journey south to warmer grounds and swathes of rowan berries are beginning to turn crimson. With still a week and a half of August left, this feels a bit premature, especially as there’s barely been a chance to pick a blackberry before they’ve gone over and turned into mush!

But shifting seasons is a reality and directly linked to climate change, and it goes much deeper than what we observe on our daily walks or drive to the shops. Changes in the timing of natural events such as the warming of the soil in spring or songbird migration can have harmful effects on ecosystems. Different species respond to different environmental cues, therefore resulting in species that rely on one another becoming out of sync. So for me it might mean an earlier and smaller blackberry crumble, but this shift is a much greater issue for plants and animals.

Sea-sonal Changes

Similar to that of the land, the marine biome experiences seasonal changes that are a critical driving force for natural events. Sea temperature, sunlight and ocean currents all play a triggering role. Plants grow and animals spawn, reflecting what’s happening on land, only sea temperatures lag about a month behind that of the atmosphere. The migration of leatherback turtles, which come from tropical waters to the Irish Sea in the summer and autumn months to feed on jellyfish and the growth of seasonal seaweeds, which provide important habitats for marine wildlife; these are just two examples of seasonal occurrences in the waters surrounding Wales.

Plankton shifting polewards

Minke whale’s are the smallest of the baleen whales, and feed on plankton using their mouths as filter feeders. Photo Credit: Eleanor Stone

But perhaps one of the most important events is the blooming of plankton. Acquiring its name from the Greek work ‘planktos’, meaning wanderer, plankton forms the basis of many marine food chains. Plankton blooms when water temperature, salinity and nutrient availability in the correct amounts are all favourable, and these conditions vary for each species. Phytoplankton are microscopic plants, and zooplankton are microscopic animals which feed on phytoplankton. From jellyfish to baleen whales, a great number of marine animals depend on plankton for food.

Lion’s mane jellyfish (Cyanea capillata) feed on zooplankton along with fish and other jellyfish. Photo Credit: Alexander Mustard

Yet, a recent study on zooplankton published in the journal Nature shows that this microscopic but vital fodder is shifting pole wards in response to climate change and an increase in ocean temperature. In fact, it’s found to have moved a whopping 602 Km on average since pre-industrial times. Apart from being greatly concerning for the marine species that rely on zooplankton, this study demonstrates that marine ecosystems have now entered the “Anthropocene”.

Photographs of plankton taken through a microscope. The far left is a zooplankton species, with the right hand two being phytoplankton. Photo credit: Allan Rowat

Why only talk about one study? Being at the bottom of the food chain within the world’s largest ecosystem, and the basis for all marine life that lies above it, the movement of plankton is highly indicative of what’s happening to other marine species too. Therefore, this study demonstrates the shifting of plankton is just the tip of the iceberg.

So the next time you see a berry ripen on a tree early, or you’re wondering why where did the last frost of the winter go, take a moment to ponder the sea, and what the seasons are doing beneath the surface of the ocean.

A Tern of Events

Renowned for being home to over 3000 pairs of Arctic terns every year during the breeding season, the Skerries provides an extremely important habitat for ground nesting sea birds, including terns, puffins and gulls. The group of small islets are located about 3 km off the north-west coast of Anglesey. Their rough, rocky terrain combined with sparse vegetation makes them inhospitable to humans. Yet for nesting sea birds, they provide the space and conditions to host thousands of broody pairs.

Taken from the shingle ridge at Cemlyn, looking towards the colony ‘dreading’


Over the past few years, the Skerries (managed by the RSPB) have been in the news due to the success of increasing pairs of roseate terns, which are the UK and Europe’s rarest seabird. Roseate terns like to nest in amongst other terns, and the Skerries allows them to do just this, nestling in amongst the Arctic terns, along with over 300 pairs of nesting common terns too. Sadly, this year the news is not that of success, but a failure of the entire tern colony.

Wardens, who spend the season observing the colony, stepping in if anything looks untoward or like it might be detrimental to the success of the colony, typically look after the reserve over the Spring and Summer months However, this year was different. With Covid-19 restrictions and furloughed staff, the RSPB were unable to position wardens on the islands, which seems to have been critical.

An Arctic tern. Photo credit: Gillian Day

A pair of peregrine falcons nested on the Skerries, which was most likely to have been the cause of the desertion, and could have been mitigated against had wardens been present. This unfortunate event highlights just how important it is to have people on the ground looking after these birds. It is crucial that tern colonies are wardened as loss of habitat and disturbance by people has made it much more challenging for terns to breed.

The colony island at Cemlyn on a calm day


Yet all is not lost for this year! Terns are adaptable birds, and have the ability to move and re-colonise swiftly. Luckily for Cemlyn, our reserve situated on the north-west coast of Anglesey, not so far from the Skerries, we have welcomed many more Arctic and common terns to the colony. Many of these have settled quickly, got down to business, and are already incubating eggs after being there just a week or two. We believe we’ve inherited at least another 1500 terns, making it the most successful year for common and Arctic terns recorded at Cemlyn. Where they’ve found space amongst the 2000 pairs of breeding Sandwich terns, 130 breeding pairs of common and Arctic terns that were already there, not to mention the nesting black headed gulls, we will never know! But Cemlyn is a noisier and more hectic than we’ve seen it in recent years, and it’s a marvel to watch! Then again, it’s been lucky enough to continue to be wardened throughout Covid-19.

What happened to the rest of the terns that deserted the Skerries? We’ve yet to find out. Some will have gone to other colonies, and in time we will know more. For now, we are keeping everything crossed for the success of the Cemlyn colony, and we hope to see more returning in years to come!

In these unprecedented times, our Cemlyn terns are in need of help. To find out more information about the Cemlyn appeal, please visit our Cemlyn Appeal.

For more information on the conservation of the roseate tern, check out the Roseate Tern Life Project.

From World Oceans Day petition to a lifetime of action?

World Oceans Day Aberystwyth 2019

On the 8th June we celebrate our oceans (and seas) for “World Oceans Day”. The day became an official UN global Awareness day in 2008 and has been growing since; last year there were officially 2000+ events in 140 countries. The Living Seas Wales team was close to our border between North Wales Wildlife Trust and The Wildlife Trust of South and West Wales celebrating the day with Chester Zoo volunteers in Aberystwyth. It was a huge day of awareness-raising in many forms and incorporated a march organised by “Extinction Rebellion” to protest against the Seismic testing for oil in Cardigan bay, a threat which galvanised many groups to act for several environmental reasons, including Living Seas.

Seismic testing in Cardigan Bay protest - organised by "Extinction rebellion"

Seismic testing in Cardigan Bay protest – organised by “Extinction rebellion”

We all know a day is not enough, but how can we raise awareness of the need for people to help our marine world in their EVERYDAY lives, without them becoming immediately overwhelmed?


The answer could come from the Wildlife Trusts 30DaysWild campaign. The Wildlife Trusts are in a unique position in that they are a group of localised Conservation charities all working under a larger umbrella organisation. 46 in total they know their local patch and know just how important local/individual actions for wildlife can be. This unique position is translated into their popular yearly campaign encouraging people to connect with Nature every day in June – #30DaysWild.  The hope is that people will begin to understand their own need for nature on a daily basis and to see how their own individual actions can be part of a bigger picture of conservation across the UK. Time in Nature has been shown to benefit us

30DaysWild action

30DaysWild action

“In the current nature and climate emergency, we’re seeing more people affected by eco-anxiety – feeling overwhelmed by the damage to our environment and not knowing what to do to help. This, along with other stresses, aren’t good for us. But with 30 Days Wild from the Wildlife Trusts you can incorporate some simple nature-based activities into your daily life and feel the benefit. These activities can lower blood pressure, take our minds away from our day-to-day concerns and help us relax, as well as providing simple ways to help wildlife.” – Dr Amir Khan, GP and Ambassador for The Wildlife Trusts

But does doing small things actually help to make a difference? Small acts done by enough people, visibly, can be become the new norm and makes those small acts huge movements. Both World Oceans Day and 30daysWild highlight the Think Global:Act Local philosophy. This year the World Ocean day theme is 30 by 30. They’re calling us all to ask our leaders to help protect 30% of the marine environment by 2030. We can do that can’t we? The one small thing you could do today is to sign the petition to help protect our oceans. The one big thing you could do today is to share your act for nature with others. One of our team was once asked by a colleague how do you stay positive when working to combat the huge difficulties facing our natural world. Their answer was they were able to stay positive from the knowledge they were at least doing SOMETHING and knowing you’re not alone means that’s a lot of people doing something.

Last year’s World Ocean day and the events surrounding it shows what can happen when people who have developed a love of wildlife, Nature and the environment take action. Let’s not forget the huge Climate marches last year which brought together a variety of organisations who are still working to help. We’re going to keep on working to protect our oceans and we hope you’ll be ready to join us.

Dinas coast

Dinas coast

(we want your) Memories of wildlife in our sea

The family and boat at Amlwch - Peter Williams

Our knowledge of our seas comes in part from decades of research by many organisations, but this is only a limited view of our marine wildlife. So much more information can be gleaned from people who spent time in the marine environment, if only people realised the importance of their own or their family’s stories.

Historical marine ecology is a scientific field where photographs, archives, news etc. are used to better understand the historic changes our seas have faced over time and this can establish a baseline against which conservation efforts can be measured. The value of these seemingly frivolous accounts is highlighted in a project which documented the loss in the diversity and reduction in size of fish in the Florida region, by collating photographs from fishing competitions from 1950s to present days. The change is striking just in the visual sense, when you look through these pictures.

Much work to conserve our marine populations has been limited to reversing declines to life as it was in the lifetime of those helping to conserve and this has been subject to a phenomenon known as “Shifting baselines”. We tend only to perceive the loss that we’ve seen not the loss from the generations which have gone before. The idea is best described by the person who coined the term, Daniel Pauly himself.

As well as being valuable for marine conservation the information will also become a collection for everyone to view online.

Closer to home we know of many regular wildlife sightings and fisheries which have changed (some examples being whaling, basking sharks, oysters, salmon, etc), but we would like to know more from your personal/family accounts. So we’re asking for your help. As part of a project we’ve developed within the online resource Peoples’ Collection Wales we’d like to collect people’s memories of coastal wildlife and environments in Wales. We’re looking for memories of our living seas from your childhood, stories you heard from your parents or grandparents, family friends or even more recent experiences that stand out in your mind. These can take the form of written or voice recordings of stories, uploads of photographs, and/or pictures of memorabilia, or other coastal items. As well as being valuable for marine conservation the information will also become a collection for everyone to view online.


We’re hoping to collect information such as

Fishermen at Amlwch - Peter Williams

Fishermen at Amlwch – Peter Williams

Ben Stammers as Warden - Ben Stammers

Ben Stammers as Warden – Ben Stammers

family photos - Steve Palin

family photos – Steve Palin

Dive log entry - Kevin Hawke

Dive log entry – Kevin Hawke









  • Stories/photos relating to marine/coastal wildlife stemming from work, holidays, life at the coast
  • Fishing catch records
  • Records of wildlife sightings (one off or timings when see each year)
  • Regular coastal wildlife occurrences.
  • Pictures/memories of the coast before development
  • Memories/pics of what you used to find washed up on the shore or in living in rock pools
  • Memories of the numbers and types of breeding/roosting birds in an area
  • Memories of incidents relating to the sea (pollution/storms/spillages etc) and its effects on wildlife.

If you have some memories or know someone who does, please spread the word and get in touch with us. If you’re part of a community group where a few people would like to offer items/stories then please get in touch too.


We’ll leave you with the chance to see and hear some of what we’ve had so far.

Peter Williams provides us with an excellent insight into life during WWII and his community’s part in the herring run in 1950s. He also describes his legacy – the dying art of willow lobsterpot-making.

Kevin Hawke shares his dive logs, documenting the wildlife he was seeing under the waves in the 1990’s off Pembrokeshire.

Gwyneth Thomas originates from Holyhead and remembers how her family managed to eat well from the sea during WWII

Steve Palin recounts a vivid memory from Porth Dafarch in the 1960s when as a child he holidayed with his family and swam in what sounds like an eel-soup there were so many.

Ben Stammers relates a snapshot of his conservation work at Cemlyn when the wardening encompassed looking after the last roseate terns to breed there in the 1990s and having to deal with egg-collectors amongst other tasks.

Spring on the shore

Shanny eggs - Allan Rowat

Cover picture: Shanny eggs – Allan Rowat


We’re well into spring on the land, but did you know our sea has its seasons? Our marine wildlife doesn’t have to deal with the larger changes of temperatures the land has, but there are very definitely events which occur in our sea which are triggered by increased light conditions and which have a knock on effect for our wildlife closer to home.

Some marine species release eggs and sperm and use the medium of the seawater to bring them together and then to disperse the developing eggs. The emerging young can then make the most of the plankton bloom to feed on and grow further. In the space between the tides, however, there are many creatures choosing the variety of places to attached or hide their eggs and are laying them locally. So, please take care; careless movements, seaweed moved and not replaced and stones left upturned can crush or dry out the eggs and any animals living there. It really is a very delicate time for these important parts of our marine ecosystem.


Doto coronata

Doto coronata – Allan Rowat

D. coronata laying eggs - Allan Rowat

D. coronata laying eggs – Allan Rowat

Sea lemon eggs - Allan Rowat

Sea lemon eggs – Allan Rowat



Seaslugs are mating and laying and can come into shallower areas to do this. Different shapes of ribbons can give you the key to identify which species laid which. Some of our other molluscs are also using weed and rocks to attached their eggs, keeping them shaded and moist until they hatch.






Crabs have to wait to moult before they mate and then, instead of laying, they use this intertidal shore area to hide whilst they keep hold of the eggs under their tails. A tricky time for these females, so any found must be returned immediately. Some rockpool specialist fish will be preparing to lay as well. They will lay their eggs on rocks, but they will hang around and protect them from predators, which makes it all the more important to make sure they stay where they’re found. A nursing blenny is a very diligent creature, if allowed to be.


Netted dog whelk eggs - Sophia and Ann Wake

Netted dog whelk eggs – Sophia and Ann Wake

dog whelk eggs - Allan Rowat

dog whelk eggs – Allan Rowat

berried shore crab - NWWT

berried shore crab – NWWT








Marine life turns its cycle, but it has to do so within very difficult times for our seas. As well as choosing sustainably-sourced seafood and adopting a lifestyle which helps to reduce your carbon footprint and waste, you can spread the word to take extra care on the shores, to ensure the life in this treacherous zone between the tides is allowed to continue without too much disturbance from us.


Want to learn some more?

Not all breeding takes place in spring, some animals will breed all year round, see our previous post about shark eggs

You can get ready for your next trip to the shore with the family. You can find plenty of spotter sheets to use when you’re next safely on the coast. Here’s our marine egg spotter to use or just introduce yourselves to, in preparation.

You can read more about one of our most enigmatic rockpool specialist fish by heading to the Blenny pages of Paul Naylor’s website, including this lovely clip of a blenny dad doing the housework, as i’m sure are the human male representatives in these strange times. He also used to help with the very entertaining, Benny the Blenny’s blog. He’s not blogged for a while, but you and the family can get a great insight into his life from his previous posts.