Roa Island Shore Walk July 2021

July 29th, 2021
Discarded fishing line.
Discarded fishing line – sadly our first find…

Our first Roa Island shore walk this year took place on Saturday 24th July.  Understandably, given the late decision to hold this, turnout was lower than normal but 5 of us had an interesting time scouring the shore for life. Sadly the first find of any interest was 30-40m of discarded fishing line tangled in the wrack under the walkway to lifeboat station. This took about 20 minutes of patient work to disentangle it so that it could be taken away for disposal. Thankfully the rest of the beach was relatively clear of litter!

Pacific oysters (Crassostrea Gigas). Photo Lewis Bambury.
Pacific oysters (Crassostrea Gigas)

We saw quite a large number of Pacific oysters Crassostrea Gigas (sometimes known as Portuguese Oyster).  These are a non-native commercial species; it’s possible that they have originated from oyster farms in the Menai Straits, although there is an oyster hatchery on Walney Island that puts some immature stock in the Bay to grow on before selling them on to other farms to mature and this may be the source too.

Dislodged sponge, photo Lewis Bambury.
Dislodged sponge

It was noticeable that there were quite a few large pieces of dislodged sponge and sea squirts, probably from deeper water, at the low water line.  It wasn’t clear how these had been dislodged, whether it was manmade disturbance – we didn’t see a dredger while we were there for instance – or a natural process, but it did bring some species to view that we may not have seen otherwise.  For instance these Oaten Pipe hydroids (Tubularia indivisa) living on one of the detached sponges.

Mysid shrimp. Photo Lewis Bambury.
Mysid shrimp captured in a shallow water trawl. Photo Lewis Bambury.

Barry tried some plankton trawls in the shallows where large numbers of mysid shrimp and small (juvenile) fish were swimming against the incomming tide, hoping for it to bring them supper! Microscopic examination revealed a phytoplankton community dominated by pennate diatoms (Proboscia alatum and Rhizosolenia sp.), though we did see one centric diatom Odontella mobiliensis. The trawl also contained some lanceolate Naviculacea (Pleurosigma sp. – probably angulatum), and one example of Bacillaria paxillifera; these are typically benthic/surface dwelling diatoms, but very commony found in shallow water trawls. There were also a number of periwinkle (Littorina littorea) eggs and newly hatched ‘velligers’. Juvenile periwinkles (the ‘velligers’) are planktonic, and use cillia covered extensions of their ‘foot’ (called a ‘vellum’) to swim. This mode of propulsion is very effective in the smaller juveniles, allowing them to make respectable swimming speeds (Olympic qualifiers – for ther size!) as they actively hunt for food, which is usually smaller zooplankton.

Periwinkle egg about to hatch. Micrograph by Barry Kaye.
Periwinkle egg containing two velliger embryos – very close to hatching! Micrograph by Barry Kaye.

Lockdown has meant that the best tides for this have passed us by this year, but this was the first of two dates that we picked as having the chances of interesting finds.  The timing of Spring tides around Morecambe Bay means that the very lowest tides – when we have the best chance of finding some of the creatures that are normally hidden – happen around 6 or 7 am, of 6 or 7 pm, so daylight times are a factor in choosing dates too. 

Our next walk is on the calendar for Wednesday 8th September at 19:00 (Low water 0.95m at 19:42, just before sunset).

Report by Lewis Bambury with additions on microscopy by Barry Kaye.

Posted in Events, Science, Shore walks

Honeycomb worm reef

March 11th, 2021
Honeycomb worm reef on Bispham beech, by Toni Roethling

The honeycomb worm (Sabellaria alveolata) is a small filter feeding worm that, in common with many similar species, binds a layer of sand or shell fragments about itself for protection. Living close together the worm tubes take on a hexagonal shape, and a large group of worms form a reef that looks a lot like a honeycomb. The ‘reef’ can be upstanding, or grow over a boulder, but is equally often seen as low tussocky structure which may be partially hidden under seaweed, as found off the promontory below St Patrick’c Chapel, Lower Heysham.

Thanks to Toni Roethling for the photograph above, taken on Bispham beach. Toni reports that the reef was a great attraction for starfish and gulls.

You can read more about the honeycomb worm on Wikkipedia.

Posted in Shore walks

Beach survey 2020

August 7th, 2020

The opportunities for communal beach surveys this year are a bit limited, but you can still enjoy a visit to the beach for a (socially distanced) walk or rock-pool hunt, and we have plenty of good beaches to visit around the Bay (so there is no need to crowd!) As we cannot be with you to help you identify what you have found this year; I include a few resources below that might help – so take a photo of what you find, so you can look it up later!

Online photographic guide

Beach finds around Morecambe Bay.
Walking the beaches around Morecambe bay you will find lots of shells – many from cockles – shown live underwater top right above. You can also find evidence of more interesting dwellers in the deeps though: The cuttlebone was one of a pair we found at Half Moon Bay in August 2015 – a live cuttlefish is shown bottom right. Occasionally you will find a dead dogfish on the beach – trapped in the rocks at Heysham point, perhaps, but at the right time of the year you will find lots of mermaid’s purses, which are their egg cases!

National MCS has a nice photographic guide to UK coastal wildlife, which you can access through the link below. The photographs are mostly taken underwater, in the plant or animal’s natural habitat, so you may need to look carefully at a specimen you find in the strand line.

https://www.mcsuk.org/ukseas/search

Jellyfish survey 2020

Photo showing two common jellyfish underwater.
The most common jellyfish in the Bay are the Lion’s mane (above left) which can give you a nasty sting (you can see masses of stinging tentacles hanging below the animal in the photo), and the Moon jelly (above right), which is harmless. Lion’s manes can grow to over one hundred meters in length – including their tentacles – making them one of the largest animals on the planet!

Jellyfish are voracious predators on plankton and smaller animals at sea. They live seasonal lives, most die over winter, with a new crop appearing in late spring, and multiplying rapidly to form vast swarms. Fish competed with jellyfish for food, but in some parts of the world, over-fishing has removed this competition, and Jellyfish swarms can become very large indeed.

Unlike fish, jellyfish are not powerful swimmers, and in late summer large numbers from these swarms can be washed up on beaches – where you will often find them beached from the strand line to the water line.

Take care approaching stranded jellyfish – they all rely on stinging cells to paralyse their prey so their tentacles can bring it to their mouths to feed. Jellyfish that live on plankton are safe to handle, but jellyfish that take larger prey items – like small fish – are heavily armed, they will cause painful stings. If you are not sure what you are looking at, don’t touch it, and be aware that fine tentacles may spread out for some distance around the main body or bell, and can stick to shoes, buckets, spades or clothing, and give you a nasty surprise after you have left the beach!

National MCS has a helpful guide to common UK Jellyfish online at the address below. Most of the Jellyfish around Morecambe Bay will be wither Moon Jellyfish (safe), or Lions Manes (look like burst tea bags – can give you a very nasty sting), but we occasionally get rarer individuals or swarms.

You can use the online guide above to identify what you have found, and report more unusual findings to the National MCS below

https://www.mcsuk.org/sightings/

Local help

We will be happy to try an help you identify plants and animals you find on the beaches around the Bay – if you can take a photo and email it to us at: strandline_AT_lancashiremcs.org.uk (replace _AT_ with @). Please tell us where you found it, and whether or not you are happy for us use the photograph on this website.

Barry Kaye

Posted in Science, Shore walks

Chorda filum: Interesting sealife from the beach clean

September 23rd, 2019

During our beach clean on Sunday (22nd September) litterpickers found a number of rather strange cord-like objects in the strand line. The objects were generally translucent white, and resembled silicone rubber beading, of the type you might use to seal around the bath or kitchen sink. I brought a sample back home for closer investigation; it was 2.5mm in diameter, and held between tweezers, could be readily stretched by 20 of its resting length (a test section extended readily from 10 to 12cm), and recover apparently undamaged – so, rubber?

The mystery was quickly solved under the microscope, where the cellular structure of the material was evident. The samples were of Chorda filum (I call it sea-whip when I see it diving – for obvious reasons, see the photo below- but I think its common name is actually ‘sea lace’). I couldn’t find any reports of the histology of Chorda filum on the web, so I present a quick report into what might be the rubberiest plant on the planet below the photo!

Chorda filum or sea lace photographed off the south end of Gigha by Barry Kaye June 2018.
Above: Chorda filum living in shallow water of the south coast of Gigha: The fronds can be extended by 20% of their resting length – is this the rubberiest plant on the planet? (Photo BK)

Histology of Chorda filum

Generally seaweeds have very simple internal structures. Microscopy might reveal a gelatinous/slimy outer layer secreted by an organised skin or dermis, but there is rarely much internal structure to speak of. Seaweeds don’t need to transport water and salts from roots to leaves, as they are continually bathed in seawater, they can rely on diffusion for most transport requirements, so generally they lack the complex vasculature we see in higher plants.

Chorda filum, however, shows a very clever internal architecture; a central lumen stretches up the centre of the entire filament that constitutes the plant’s body. The lumen is surrounded by four or five layers of large box-like cells. These cells are at an angle to the axis of the filament – so they coil like a spring down the plant. This almost certainly contributes to the plants amazing elasticity, though I would not be surprised if there were not further mechanisms at the molecular level.

A thick transverse section through the stem to show the pitch of the box cells.

The box-like cells showed no internal structure in the sample I had from the strand line, but in places there was evidence of a further layer of cone-like cells attached by their apex to the outside of the tube of box-cells. These cells had clear chloroplasts in the wider end, suggesting that photosynthetic activity had been an important role in these cells while the plant was alive. I confess that I don’t understand why these cells are only attached at their apices, but this again might be to allow movement required as the plant is stretched and relaxes as each wave passes over it.

Longitudinal section showing the oddly shaped surface cells with narrow attachments to the main plant, and chloroplasts packed into the wider outermost part of the cell.

In conclusion; many seaweeds live in extreme environments. Chorda filum seems to have evolved a particularly interesting way of coping with the mechanical stresses of wave motion, and this may be one of the factors that permit it to colonise seabeds that lack good points of anchorage.

By Barry Kaye

Posted in Beach Clean, Science, Shore walks

Risk and reward – the Roa Island shore walk 2019

September 2nd, 2019
Sand mason worms against the sunset at Roa, August 31 2019. By Barry

The drive up to Roa on Saturday was not very promising, with periods of torrential rain it was no surprise that only a few made the effort… In the event, however, other than a strong wind, the evening was very pleasant. We spent the first little while, however, spelling one of the lifeboat crew watching some kayakers to make sure they reached Piel Island safely!

Due to the wind we spent a little more time than usual to the West of the lifeboat jetty. The mud flats here are the home of a large number of sand mason worms (pictured above), and scattered with common starfish, which have been stranded by the tide as they hunt for cockles in the mud. Starfish have a hydrostatic skeleton, so are completely incapacitated in the absence of water. It is clear from the sad, deflated bodies, that a few do not survive exposure, but for many the chance of a meal must be worth the risk…

The visit also allowed me to take a plankton sample, which looks very different to the one I took on the dive in July, when there were no phytoplankton, and few zooplankton. The rougher weather recently may have helped spur some activity, as the sample from Saturday had high concentrations of phytoplankton, and lots of zooplankton and larvae, to recolonise the Bay. A few weeks can make a massive difference!

Barry Kaye

Posted in Marine science update, Shore walks

Roa dive July 2019

July 29th, 2019
Scorpion fish hiding on the bottom at Roa, 26 July 2019, by Lewis Bambury.
The scorpion fish Taurulus bubais (photo by Lewis) waiting for something tasty to swim by (thankfully we are a little too big for it).

After a string of possible dates this year that we were unable to get in at Roa Island we finally managed a dive on Friday (we had to bring it forward a day to miss the worst of the weather). It was well worth the effort. Visibility was only 2 to 3 metres at best but that is plenty to search the reef for interesting macro life. Our species list – which for invertebrate species goes back to 1968 – grew by at least 2 new species. First to be found were several Goldsinny (Ctenolabrus rupestris), unusual not just as a first for that species, but the first species of wrasse to appear on the list.

Goldsinny, photo at Roa by Barry Kaye, July 2019
Goldsinny, photo at Roa by Barry, July 2019

The next was a nudibranch (that’s a fancy name for a sea slug) called Jorunna tomentosa (pictured below) – it doesn’t have an English name. Both are common species around the coasts of the UK, so of course may have been here all the time, but this is the first time we have them on record here.

The nudibranch 'Jorunna tomentosa' photod by Lewis Bambury at Roa, July 2019
Jorunna tomentosa feeding on one of the sponges (possibly Haliclona sp.) common at Roa. Photo by Lewis Bambury, July 2019

There are many predators in the marine ecosystem and animals have a variety of strategies to help them find food, and avoid being eaten. The Long-spined Scorpionfish is a master of disguise – hiding in plain site by blending its skin colour in with its background; if a crab or small fish comes too close they will be grabbed at lightening speed, predators large enough to tackle it will need sharp eyes to see it, and if they do this fish has a back-up plan – the eponymous long spine on its gill cover, just visible in this picture.

Perhaps the most suprising thing about the dive was the water temperature – depending in depth it ranged from 18ºC to 20ºC. I don’t think that I’ve dived in water that warm either at Roa Island or anywhere else around the Irish Sea. Unfortunately I can’t check my dive logs after a computer glitch trashed them a couple of years ago.

Thanks to Philip and Rebecca for providing shore cover!

Lewis Bambury, July 2019.

Posted in dive trips, Shore walks

The scar at Sandylands

June 6th, 2017

Walking out to the Sandylands fishtrap with reef or scar in the background.

I think we approached the evening of Saturday 27th May with some concern, the hot weather earlier in the week had turned to heavy thunder storms, and our walk accross to the scar at Sandylands looked rather questionable! In the event the weather abated, and the rain only appeared on our walk back, allowing us to enjoy a rather interesting and historic marine landscape.

Scars (or skears) are a common geological formation in the Bay, periodically adding a bit of texture in the form of glacial boulder-clay deposites to flat mud and sands. Off Sandylands this feature has clearly been of historic importance, given the number of posts indicating fish traps. Apparently these had been in use until the early 1960’s, and while they looked like conventional fish traps, (a ‘V’ shape narrowing to trap the fish in its point as the tide goes out), anecdotally they may have been associated more with mussel farming. Indeed the reef is in part covered by a large mound of mussel shells. Interspersed in the mussel shells were oyster shells – our local species of oyster was wiped out by disease a hundred years ago, and these worn shells my have been relicts of the time when they were still plentiful.

Gordon talking about some of the finds

Many of the boulders in the scar were completely covered in barnacles, or the swirling patterns of the honeycombe worm reefs. Other animals of interest included anemones, sandhoppers, a grey nudibranch, and tiny common and hermit crabs, that have recently settled to the bottom from their planktonic larval stages.

All in all, an excellent and educational experience. Many thanks to Gordon for organising this, and making an appearance despite having raced in the thunderstorms earlier in the day!

Atmospheric walk back to Morecambe

Posted in Events, Shore walks

Roa Island survey

April 28th, 2017

Roa shore walk group April 2017

A big thanks to everyone who turned out for the beach walk and survey at Roa on Thursday night. The weather did not look very promising in Lancaster, but it was very sunny (though a cold wind) at Roa.

We split into two groups: The main group took a look at the life in the rock pools below the Lifeboat station, always a good hunting area, and saw a wide range of life, including plumose anemones exposed by the extreme low water. The high spot included a small lobster, I think the first time we have seen one on a beach walk, though they are a fairly common sight when diving at this time of year.

I turned to the rather less glamorous task of running a transect down the beach, which proved to be quite hard to complete before the tide turned!

Photograph of a curled octopus

We were joined by Albert towards the end of the evening; he spotted the star find – a curled octopus swimming in the surface waters within a meter of the shore. – I have added the photo above due to popular demand! The octopus was bright red in the water, but quickly changed color to white on capture. He (or she) returned to the original red colouration on release, and continued surface swimming…

I was asked about the guide we were using – this was ‘Seashore Safaris’ by Judith Oakley, and is published by Graffeg.

Posted in Shore walks

World Ocean Day at Freeport Fleetwood

June 24th, 2016

Thanks to everybody who made the recent World Oceans day at Freeport Fleetwood such a success. Trawls in Fleetwood harbour resulted in us finding and identifying nearly 50 species, many of which were available for visitors to Freeport to see, and touch – before being returned safe and unharmed on the Saturday evening! Stars of the event included a European eel, a lobster, a greater pipefish and several species of flatfish.

More from this event on That’s Lancashire TV (via YouTube):

Posted in Conservation, Events, Marine science update, Shore walks

Heysham Safari

September 28th, 2015

Photograph of children rock-pooling at Heysham safari 2015

The Bay ‘Super-Estuary’: After the last ice age, the ice sheets that scoured out Morecambe Bay retreated, leading to the formation of the Irish Sea, and flooding the Bay itself. While it still reaches depths of 80m at Lune Deeps, most of the Bay has been filled in with sediment brought down by the rivers Wyre, Lune, Keer, Kent and Leven to form the largest network of intertidal mudflats in the UK.

Satellite imagery shows that the bay as a whole has a very high primary productivity. Fixing around 1.5kg of organic carbon per square meter every year, this ecosystem is one of the most productive in the world. Despite this powerhouse of growth, life in the Bay tends to keep itself hidden, so on Saturday 28th September, Gordon Fletcher led a ‘Heysham Safari’, to expose some of its less commonly spotted inhabitants.

The event, organised with Morecambe Bay Partnership, was a great success, with twenty five participants filling the restaurant at the Royal Hotel, Heysham, for Gordon’s talk! The talk was followed by a shore walk around Throbshaw Point, where we found and identified 26 species in a little over an hour.

Thanks to everyone for attending, and helping to make for such an enjoyable occasion!

Posted in MCS talks, Shore walks