The Écréhous

Posted by Graeme Lyons , Wednesday, 17 September 2025 17:25

This time last year, I had never even heard of the Écréhous. Now I have been lucky enough to spend two days and nights there snorkelling and rock-pooling, all courtesy of Nicolas Jouault. I literally went on holiday from my own holiday. The Écréhous are some small uninhabited islands and rocks in the sea off the north east coast of Jersey, not quite half way to France. It falls under the Bailiwick of Jersey, and therefore counts on your pan-species list! Along with the abyssal plain off the western coast of Ireland, this is one of the areas we decided counts that few pan-specie listers, if any, have ever recorded in. Now the key target for the entire Jersey trip was the nudibranch Berghia coerulescens. I'll come back to that. Oh and I started with my favourite photo from this trip, a stonking male Black-faced Blenny (by far the commonest fish there). Look at that dorsal fin!

Here's Nick loading up his boat.


Leaving Gorey Harbour past Mont Orgueil Castle. It was a pleasant and uneventful crossing, with a few Manx Shearwaters and terns the only wildlife.


Although I could see the Écréhous from the actual room of our accommodation at Bouley Bay, this was my first proper view of the islands.


The main clusters of huts on the Écréhous. It's an incredibly unusual place.


Here's the view looking back towards Jersey. When the tide went out, we went out snorkelling just in front of the end of that rainbow.

I was really lucky to get out there at all. The ferry on the Wednesday was cancelled, Thursday fully booked (and alas, also cancelled) and the next one wouldn't get us in until Friday afternoon - too late for the Écréhous. So we went a day earlier. Hence why the holiday just kept getting longer and longer. 

We snorkelled on days one and two, and rock-pooled on the last day due to higher winds. This is really the first proper snorkelling I have done and it was a steep learning curve. Turning rocks in a foot or two of water is really interesting, it's like being in zero g, you have to think a lot about the physics of it all. I also learned that the annoyingly high temperature I always run at steams my goggles up and I have to wipe them every 15 minutes or so. This is a radical change for me, the first time I got in the water was only last September. I was terrified of putting my face in the water after being a poor swimmer my whole life. I must admit, I am much more comfortable when I can see the bottom. Now you can't get me out of the water, it's like I have grown gills. I think we did three hours each time and it seemed like less than an hour.

Anyways, I'll start with the fish. I was playing around by the jetty before we headed out and I spotted a fish, more importantly my 99th fish! Common Dragonet! These are beautiful fish up close but they were not easy to get close to.

We saw a few Topknots. I was just using my TG-7 here and the light was very bright above with a light breeze, leading to these rainbow like bands. I needed to cast my shadow over the subjects but I don't have the light setup for that.

Then I spotted this tiny fish with an odd fin near the front, I did not realise at first that this was a young Black-faced Blenny. Until I went on to see dozens on them! Just look at these beauties. My 100th fish!

Moving to a new area we swam over these young Black Sea-bream!

On the second day there were some small areas of Eelgrass in the pool we were snorkelling in. It looks amazingly beautiful under the water when floating vertically.

As I swam around the corner, I came face to face with a shoal of young Pollack. It was beautiful. But wait, there's something different in with them!

In fact, in this shot you can see three species. Pollack above, more young Black Sea-bream in the middle I think (although they are much plainer and buffier than the ones above) and below a Striped Red Mullet! Yet another lifer, fish species 101!

This Lobster was a bit of a shock, I was rather pleased to get my face away from those claws.

Time for some nudi-action. The commonest sea slug there by far was Pruvotfolia pselliotes. A beautiful sea slug with a hateful scientific name like a pile up in the mouth. Try saying it with a snorkel in your gob! I love the tiny white spots on the mantle. The cerata sometimes look like sparrow's wings.


A few of these large Geitodoris planata were quite impressive.


So, are you ready for the money shot? I give you, Berghia coerulescens. Yeah, we only found the eggs and then just one spiral. Despite ten days of constant rock-pooling and snorkelling, it seems the population has crashed just a couple of years after they turned up on the islands. In PSL terms, we count all stages (I have ticked Kentish Glory from its eggs). If it's good enough for a record, then it's OK on your list BUT I still feel like I have not seen the species. I will have to go back out to Jersey soon! It's always good to leave one thing you didn't get (would rather it hadn't been this species though).


While I am it, based on the nudis Nick has been seeing out there, I am pretty sure these are the eggs of Atagema gibba (an out of water shot).

Some other molluscs. Green Ormers are such wonderous things under the water and quite fast for molluscs. 

Here's one of Nick's 'tagged' ormers. Nick tirelessly monitors different populations here and on Jersey. Recording dates, size, survival rates etc. Really important stuff for monitoring long term population trends.

I finally caught up with the smaller Lamellaria latens with its spotty underside to the mantle.

There were quite a few of these tiny, whitish, grub-like chitons which I identified as Letpochiton cancellatus.

The islands are really amazing for sponges, it's a Jackson Polack down there. Nick showed me most of these, so I hope I have got the names all right here. I think from top to bottom; Polysyncraton lacazei, Raspailia ramosa Chocolate Finger Sponge (if you left some chocolate fingers in a damp cellar for 25 years then maybe - guess it's just starting out), Chelonaplysilla noevus, Aplysilla rosea and Clathrina rubra.

On the last morning, we went rock-pooling in a a different area. Nick caught this Giant Goby! It was huge.

I turned a rock to find this large crustacean. I first thought it was Upogebia deltaura but Nick pointed me towards Axius stirhynchus. This burrowing crustacean is rarely recorded. It was interesting watching the appendages under the abdomen paddle away in the Ferrero Rocher box. My camera lens was a mess from the previous day's snorkelling, so these images are heavily edited.

Time to head back to Jersey. What an insane trip, it was one of the most memorable experiences of my life! I am eternally grateful to Nick for this. Especially as it has given me the confidence to get in the water on my own.

In fact, I was straight in the water at Bouley Bay. Although I learnt the hard way that five days of stubble lets water seep into your mask. Here is a young Barrel Jellyfish there!

And a brief attempt at Rozel where I managed to catch a Shanny with a bum bag. Imagine being that derpy.

And finally, the sea was pretty rough on the way back on the ferry to Poole, and as it doesn't stop at Guernsey any more, it went up the east side of Jersey, right by the The Écréhous! I took great joy telling everyone who would listen on the ferry about my time there. 

I have one more Jersey post in me about the terrestrial side of things but that will have to wait until next week.

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"Look sir, dorids"

Posted by Graeme Lyons , Monday, 15 September 2025 16:53

So I have just got back from the longest holiday I have had in a decade. Ten days on Jersey. After really getting the bug last September, I was desperate to get back there and get in the rock pools again and this time I timed it so I could do some rock-pooling every day for that whole period. More importantly though, I was accompanied each day by Nicolas Jouault, who took us to all the best places on the island (including a two day trip to the Ecrehous, which was so awesome it's getting its own blog post). Nick's knowledge of the island's marine species and where and how to find them is incredible and I am so grateful for all the time he gave me. Here's me, Karen, Nick and Lou Wagstaffe (Lou came out with us to La Pulente and showed us loads of stuff there - check out Lou's amazing photography here).

We did find rather a lot! Before I get to Nick's discovery of Discodoris rosi, please indulge me in this sequence of dorids, neatly setting me up for a rather stupid gag... 

We saw plenty of these Warty Doris Doris verrucosa. Not a new one for me but a pleasure to see these large nudis again. They're almost too big for the macro! 


On the second morning out with Nick, we headed to Le Hocq and Nick soon found our target species. The behemoth among nudibranchs, Dendrodoris limbata. This massive species should be handled with care, as it secretes a toxin to help it consume the sponges that it feeds on. I went on to find another three animals, including two immatures! I could not get enough of them. This was one of the key targets for me on this trip. They are a recent arrival to Jersey.


Terrible photo, but turning a rock to see Dendrodoris limbata and a Green Ormer in a 'yin and yang' like embrace is the most Jersey thing ever! There were three species of nudibranch under this rock. While I am at it, it's vital to turn rocks back the way you found them and gently too. It kills the life under them that can't move very quickly. There are some utter tools out there doing this wholesale, likely driven by illegal fishing. Just turn the rocks back, it really isn't that hard. Anyway, rant over.

We saw quite a few Sea Lemons Doris pseudoargus. A common and widespread dorid.


This one was a lifer. Geitodoris planata. Large and dark, often with pale starry patterns on them. These were at La Rocque and also the Ecrehous.


Then back to the star of the show. Nick found a bright orange-red dorid under a rock at La Pulente. We thought it was something else at first but then noticed the pale rings. It's the ridiculously named Discodoris rosi. DISCODORIS! FREAK OUT! And freak out, I did. That was the most unexpected find and completely new to the Channel Islands! Nice one, Nick. 


Here are the best of my shots. Check out the translucent bases to the rhinophores.


And finally, Grannydoris hominesis. A recent DNA test led to the discovery that I am one quarter nudibranch, explaining my obsession with these awesome creatures! You see, my late Granny Doris fooled everyone for decades - we had no idea she was a nudibranch (to be fair, I did always think it was odd that she got through so many sponges). Here she is with her rhinophores retracted, awaiting a fresh delivery of sponge from Kwik Save. Miss ya, Gran.


Anyways. Back to reality. Another lifer for me was the awesome little Celtic Sea Slug Onchidella celtica (not a nudi though). They are all over the pier at La Rocque, we saw some 50 animals in a square metre. You find these sitting out of the water quite high up the shore, they are very slug-like but cute.


Edmundsella pedata was the commonest sea slug on Jersey. I saw 50 in one day and well over a 100 on the trip.

Nice to see a tiny Montagu's Blenny right at the top of the beach. This was a four blenny trip, I think well over 20 species of fish in all. I'll cover them more on the Ecrehous post.


I got a lot of lifers in the squidgy groups, like sponges and tunicates! Here we have Pyura tessellata.

And what I have as Ascidiella scabra.

I should have warned this post goes on for ever. Aeolidiella alderi was widespread but in low numbers. We had one or two on each session.


And what I believe are their eggs. A bit of foreshadowing here. Many nudibranchs are identifiable by their eggs through experience, association and deduction...

Remember the rock I said had three nudibranchs under at Le Hocq? It had a single Dendrodoris and a couple of Edmundsella and round the edge it looked to be covered in small hydroids. I went for the close focus binocular trick and spotted a tiny bit of egg white with yellow highlights. Hold on a minute, that's a nudi! We gently got it into the lid of the Ferroro Rocher box and it was none other than Trapania maculata (turns out this was only the 4th record for the island). For the record, this was a 12 nudibranch trip!

At Rozel I found my first cup corals. These were common on the Ecrehous. This is Scarlet-and-gold Cup Coral Balanophyllia regia. 

Also there, Manilla Clam Ruditapes phillipinarum.  A recent non-native introduction to the island.

Facelina auriculata is surprisingly uncommon there. We only found two (one at La Rocque, one al La Pulente).

This place is incredible, like the surface of some alien world. Just watch these tides though, you can get caught out here easily. It's dangerous if you are not experienced and reading the tide all the time to go out far.

We found a couple of these stalked jellyfish Calvadosia campanulata, which is the one I see most often.

Nick identified this bryozoan at La Pulente, as the rarely-recorded Schizomavella sarniensis. There's so much stuff like this on the rocks, most of which I am clueless about. It's humbling but insanely addictive. I love being outside of my comfort zone.

I got very excited by this mollusc, only to figure out it's just an immature cowrie sp. (Trivia).

Round the other side of the island to Archirondel, Karen found these two Parasitic Anemones Calliactis parasitica. 

And Nick showed me this incredible sea weed there too. It's Codium bursar and is quite scarce. It feels like a sponge and well deserves the colloquial name of French Beret. 


Man, I can't get enough of this stuff. As you can imagine, I am pretty stoked. A huge thanks to Nick for all his help, time and knowledge. We were lucky with the weather but we saw no one else out recording in the rock pools. I am surprised that so few people are recording marine wildlife on Jersey. It's really important to record and submit records, so this is a plea for anyone reading this on the island or travelling there for a break, to do so. It's changing all the time too through climate change and accidental introductions and documenting these changes is really important stuff.

Furthermore, you can support the study of natural history on Jersey by joining the Societe Jersiaise here.

OK, I need a breather after all that. But I leave you with this collage that says it all really. Each of these was a lifer from this trip. I think I added about 55 species!

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