The Flintback Drifter

All in one day, amazing, walking along the Brighton pebbles, I found four different varieties of the Flintback Drifter. Unusual to see at the best of times, but four was like winning the lottery. There must have been a storm in the Channel, or some such peculiar weather system to have caused such a windfall of marine rarities.

The Flintback Drifter is a little-understood marine species that perfectly mimics flint stones, lying motionless among the pebbles of tidal zones. It is believed to be an evolutionary marvel, capable of remaining more or less inert for decades before gradually shifting into a more animate state. For those new to the species, here is a fact file.

Scientific Classification
Kingdom: Animalia
Phylum: Chordata (disputed)
Class: Lithopoda (proposed)
Order: Cryptosiluriformes
Family: Silicamariidae
Genus: Silicamaris

Species (numbered as in photos)
1) Silicamaris dormiens (Dormant Flintback Drifter)
2) Silicamaris lithomimus (Stone-Mimic Flintback Drifter)
3) Silicamaris vivens (Living Flintback Drifter)
4) Silicamaris mutabilis (Transitional Flintback Drifter)

Size: 20–50 cm (depending on life stage).
Color: Varies from deep grey to mottled black and white, mimicking natural flint and beach pebbles.
Texture: Hard, rock-like exoskin with occasional glossy fractures resembling chipped stone.
Body Structure: Appears almost featureless at rest but reveals faint ridges, a ventral mouth slit, and sensory pits when active.
Habitat & Distribution: Found exclusively along shingle beaches, particularly in Sussex, UK. Prefers intertidal zones, where it can remain still among pebbles, rarely moving except at night or during storms. Some reports suggest it may also drift along deeper seabeds, using its flint-like exterior to deter predators.
Feeding: Although widely thought to be pebble-eaters, they are slow-moving filter feeders, absorbing nutrients through microscopic pores when submerged. Some speculate it may consume small marine organisms using a concealed underbelly mouth.
Movement: Almost imperceptible. Shifts position by subtle expansions and contractions of its dense, flint-like tissue.
Defense Mechanism: Extreme camouflage. When disturbed, it remains motionless, indistinguishable from real stones.
Life Cycle & Evolution: Begins as Silicamaris dormiens, indistinguishable from a common flint stone. Over time, it may transition into Silicamaris lithomimus, showing faint organic features. Eventually, it develops primitive limb-like ridges and becomes either Silicamaris mutabilis or Silicamaris vivens (though marine biologists dispute whether these are two distinct species). Flintback Drifters may live for hundreds of years, growing at a nearly imperceptible rate, though much about these creatures remains unknown.

Cuttlefish and their bones

Walk along Brighton’s pebbles and you’ll soon find yourself kicking out at brilliant-white oval-shaped objects that seem to be littering the beach. If you pick one up, it feels unnaturally lightweight. These are cuttlebones, as everyone knows, the internal shells of cuttlefish. They are not the most useful or interesting of beach finds, though they can be ground into powder for polishing, and jewellers have made moulds for casting metals. Today, most commonly, they serve as dietary supplements for pet birds. However, A.Z.L, my 13-year old son, likes turning them into art! This is his Cuttlebone Helter Skelter. Other artists like to carve them into shapes and scenes.

Each spring and summer, common cuttlefish (Sepia officinalis) migrate to shallow waters to breed, leaving behind thousands of eggs hidden among rocks and seaweed. Shortly after spawning, the adults die, and their remains drift with the tides. Their soft bodies decompose quickly, but the cuttlebones - made of lightweight, porous calcium carbonate - float on the water’s surface before washing ashore.

The prevailing southwesterly winds push them toward shore, where they land on Brighton’s pebbles rather than sinking into sand. Unlike driftwood, which might get swept back out to sea, cuttlebones tend to linger, their ghostly forms drying in the sun. Sometimes, you’ll find them with strange marks - tiny holes left by hungry seagulls pecking at the last traces of flesh.

Cuttlefish are fascinating creatures, according to Wikipedia, sometimes called the ‘chameleons of the sea’ due to their incredible ability to change colour and texture in moments. They use this skill to mesmerise prey, communicate with each other, or simply disappear into their surroundings. Though they have eight arms like an octopus, they also have two longer tentacles that strike out to snatch fish, crabs, or shrimp. Despite their intelligence and complex behaviour, their lifespans are surprisingly short - most live only a year or two before nature takes its course - adding another cuttlebone to the Brighton shoreline.

Over time, these bones have found strange uses beyond the sea. For centuries, people have ground them into powder as a polishing agent, while jewellers have used them to make moulds for casting metals. Artists have used them to carve objects of beauty - see Stephen Hughes’ work in South Africa’s Highway Mail. Today, most commonly, they serve as dietary supplements for pet birds, providing much-needed calcium for beak and bone health. 

Cuttlefish, of course, also have ink stores used to deter predators, but they also have long served man for different purposes, as a dye (to make non-iridescent reds, blues, and greens) and for food (to darken and flavour rice and pasta).

Now you see them . . .

Brighton Beach is justly famed for its starling murmurations during the winter months. Usually as dusk approaches and before roosting for the night, many thousands of these birds swarm and swoop through the sky - between and near both piers - dancing together in what look like carefully-choreographed ensembles, thus creating the most mesmerising patterns. Crowds of humans gather on the beach and the pier, cameras in hand, to capture the sight. And the photographs they take can be made yet more photogenic (startling even!) with either of the piers in the background and/or the setting sun.

NOW YOU SEE THEM . . .

These two photographs were taken a few minutes apart last evening(the sun drops fairly quickly below the horizon line at this time of year). I was not able to capture the beautiful shapes made by the murmurations - though wonderful videos and gorgeous stills of them can be found elsewhere, such as on Facebook and Instagram. However, the above photo gives a sense, maybe, of how each bird twists and turns through the sky, painting the air with movement - pure, wild, and apparently weightless - to form a scene both serene and dramatic, a fleeting moment of natural beauty.

NOW YOU DON'T . . .

According to The Woodland Trust, thousands of starlings all swirling and swooping together means one thing: safety. The sheer volume of birds confuses predators like peregrine falcons and makes it much harder for them to pick off individual birds. The characteristic shapes of a murmuration come from the rapid changes in direction. Starlings have extremely fast reactions, so when one bird changes speed or direction, the birds around it do too. This also allows the birds to move within the murmuration itself, meaning that no one bird spends too much time at the edge of the group, where they’re vulnerable to predation. When roosting, apparently, they also like to snuggle up together for a warmer night.

Apart from Brighton, other famous murmuration sites include: Shapwick Heath, Somerset Levels (where six million birds were recorded in 1999); Aberystwyth Pier, Ceredigion; Leighton Moss, Lancashire; Fen Drayton, Cambridgeshire; Minsmere, Suffolk; Newport Wetlands, South Wales.

White arrows dropping from the sky

Found this morning on the pebbles in Hove - one bedraggled, dead northern gannet. Where did it come from, and how did it meet its final fate? One photographer has described these birds diving as ‘white arrows dropping from the sky’.  Unfortunately, not this one any longer,`

Northern gannets (Morus bassanus) are large, striking seabirds - with white body and black wingtips - which live in huge colonies on rocky cliffs and islands. Typically, they remain most of the year between late February and early October when they set out on a long journey to winter on the west coast of Africa. 

The northern gannets breed in their colonies between April and June, building nests from seaweed and other debris. The female lays a single egg, and both parents take turns incubating the egg for about 44 days. Once hatched, the chick is fed regurgitated fish by its parents; it fledges at around 10-12 weeks old. However, young gannets do not reach sexual maturity until reaching 4 or 5 when they join the breeding colonies and begin the cycle again. Average lifespan is 17 years, and their wingspan can reach 1.8 metres. They feed by circling high above the waves, before folding their wings back and make spectacular dives into the water headfirst to catch fish. They have special adaptations, such as air sacs in their chest and strong skulls, to withstand high impacts. 

The most significant colonies of northern gannets are located in Scotland. Bass Rock is the world’s largest: it had over 75,000 pairs (i.e. 150,000 individuals) as of about ten years ago. However, it was badly hit by Avian Flu, and the population was thought to have dropped 30% in 2023. Other larges colonies (over 10,000) also exist at St Kilda and Sula Sgeir (Outer Hebrides), and Ailsa Craig (Firth of Clyde). Elsewhere in the British Isles colonies are sited at Bempton Cliffs on the Yorkshire coast, Grassholm in Wales, and Little Skellig in Ireland (the latter with over 30,000 breeding pairs). 

Northern gannets are currently classified as ‘Least Concern’ by the International Union for Conservation of Nature, though they do face threats from climate change, pollution, and entanglement in fishing gear. Possible causes for the death of the gannet in these photos are: natural causes, i.e. old age, disease, or injury; exhaustion after severe winter storms; food shortages; pollution, which can weaken birds and make them more susceptible to disease; Avian Flu. More information can be found at Wikipedia and the Scottish Seabird Centre.

Richard Creagh’s website includes some spectacular photographs of northern gannets, as well as his own testimony of observing them (from 2017): ‘Gannets are the largest Irish seabird, with a wingspan just short of two metres. They are beautiful birds to watch, and what really sets them apart for me is their stunning dives. Ever since I first noticed them that afternoon in West Cork I’ve been drawn to those white arrows dropping from the sky in pursuit of fish. Diving from as high as forty metres gannets hit can hit the water at 60mph.’

Interestingly, there’s a comment on the same website from Stephen O’Melia who recalls watching northern gannets while swimming just along the coast from Brighton at Worthing: ‘It was around 3.00pm, about 90 minutes after high tide when a gannet approached a couple of women floating in the sea. It made an attempt to attack them but was eventually driven off by a third swimmer. But it circled round and attacked again. It later approached two other swimmers before flying off. This took place about 30 to 50 feet from the shore. I have never seen a gannet in Worthing before, and none of the other swimmers had either. No one was hurt but it was the persistency in the bird's approach which was surprising. We wondered whether it was unwell.’

Vegetated shingle

In recent years, much progress has been made with the Black Rock Rejuvenation project but, specifically, I am curious to know how the council is progressing its plans ‘to increase the amount of vegetated shingle at the eastern seafront’. My photographs show the allocated areas fenced off from public access earmarked to allow new growth. Although there are signs of green growth, it doesn’t appear that the planned biodiversity improvements are yet thriving.

It is now nearly five years since Brighton Council’s Black Rock project was given planning approval. Achievements since then include junction upgrades at Duke’s Mound to improve pedestrian and cycle safety; upgraded crossing points and improved existing crossing points on Volk’s Railway; refurbishment and opening of the Reading Room (see ‘Fantastic new refectory’; and a new 3-metre wide boardwalk running from the existing Volk’s Workshop in the west to the Volk’s Station at Black Rock.

Council exhibition boards to be found on display in the area give plenty of information about the various aspects of the project. One, in particular, is titled ‘Black Rock Rejuvenation - Improving biodiversity’. This states:

‘The Black Rock rejuvenation will deliver significant environmental and ecological improvements, making the eastern seafront a more sustainable, accessible, and attractive place to visit. It will include the creation of an ecology trail along with removing invasive non-native species from the Kemp Town Slopes and reintroducing native plants, wildflowers, and chalk grassland. It will also seek to increase the amount of vegetated shingle at the eastern seafront. Some of it will have to be relocated to facilitate the realignment of the sea wall. However, with the additional area to be replanted and seeded there will be a net gain in biodiversity through the provision of 1.5 hectares of vegetative shingle alongside the new beach boardwalk.’ The board also shows some examples of ‘native species that are likely to form part of the reseeding and replanting’ in the first phase (see below). 

Patches of green growth can be seen in the cordoned off areas of shingle, as in the photographs above, but a lot of the growth seems to be more weed-like than a biodiverse selection of shingle flora. Time, hopefully, will allow the kales, poppies, rockroses and buck-thorns to spread and flower.

#BrightonBeach365 #BrightonBeach #Brighton #BrightonLife #VisitBrighton #BrightonUK #BrightonAndHove #brightonpier #Blackrock

Underwater fairy lights?

Found on Brighton Beach: a golden spray of tinsel? gossamer seaweed? washed up underwater fairy lights? botanical jewellery? 

None of the above. This is actually the fine, branched stems of a species of marine hydroid called Amphisbetia operculata. Hydroids are part of a larger group of animals called Hydrozoa (within the phylum Cnidaria which also includes jellyfish and corals).

Hydroids exist in a colonial polyp form. Colonies can be a few centimeters in length, but individual polyps are much smaller. Unlike many hydrozoans that alternate between polyp and medusa stages, Amphisbetia operculata does not have a medusa stage. Instead, it reproduces by releasing planula larvae, which swim for a short time before settling and growing into new colonies.

Like other hydrozoans, it is a filter feeder, relying on cnidocytes (stinging cells) for prey capture. Though they can be found in freshwater, they mostly live in shallow sea waters, attached to rocks, shells, seaweed, or other underwater surfaces. See more about Amphisbetia operculata at Aphotomarine.

Cool facts. While Amphisbetia operculata might be considered a rather lovely but otherwise benign and uninteresting sea creature, some species of hydroids have a little more pizazz about them. For example, Turritopsis dohrnii is sometimes called the ‘immortal jellyfish’. It has the unique ability to reverse its aging process - instead of dying, it can revert to an earlier life stage and start over, meaning it could, in theory, live forever under the right conditions. 

Certain hydroids, like those in the genus Aglaophenia, can grow on discarded fishing nets, ropes, or other debris, creating ghostly underwater structures that float in the currents.

And, finally, there are some hydroids that form colonies in which different polyps specialise in different tasks (some feed, some reproduce, and some defend the colony with stinging tentacles) - making for a superorganism!

A catshark that is a dogfish

Found on Brighton Beach: a small-spotted catshark (Scyliorhinus canicula) often called a dogfish. No, it’s not sunbathing, it’s dead, probably having been scavenged (yet not consumed). Sunlight does, though,  cast a warm glow on the fish and its pebble resting place.

The slender, elongated body has a pale, creamy underside and is covered in small, dark spots. Its gills can be seen through the open mouth, and its pectoral and dorsal fins are clearly visible. The tail appears slightly curled.

The small-spotted catshark is a small shark, so named due to the dark spots and blotches covering its skin. Individuals typically grow to around 60-70 cm in length, though some can reach up to one metre. Like all sharks they have very rough skin, covered in hard ‘dermal denticles’ - which literally means ‘tiny skin teeth’. If rubbed the wrong way, the fish feel very coarse like sandpaper but this provides them with an effective chain-mail like protection. 

Catsharks are predators and feed on crabs, molluscs and other small fish. When threatened, they curl up into a donut shape - probably to look bigger and harder to eat! They are highly common around the UK, harmless to humans, and live in sandy, gravelly, or muddy seabeds. As with all sharks and rays, their egg cases are known as mermaid’s purses; these have tendrils that anchor them to seaweed or rocks until they hatch.

What about this odd confusion of names? Wikipedia gives several other names for the small-spotted catshark: sandy dogfish, lesser-spotted dogfish, rough-hound and morgay (in Scotland and Cornwall). In the early days of animal classification, naturalists like Linnaeus initially grouped most sharks under the Squalus genus (Latin for shark). Over time, scientists refined their classification, moving this particular species into the Scyliorhinus (catshark) genus in the early 1900s. However, fishermen have traditionally used the term ‘dogfish’ for any common or abundant small sharks, regardless of their actual scientific classification. 

So, if you like, you can be both a dog(fish) person AND a cat(shark) person at the same time - though not a catfish, which is something entirely different!

The carnivorous whelk

Herewith, as promised a couple of days ago and with little adornment, is the life cycle of the common whelk (Buccinum undatum).

Whelks reproduce annually, with spawning occurring between October and May. The process begins when water temperatures drop below 12°C. Females attract males by releasing pheromones, and fertilisation occurs internally. After mating, females move to hard substrates like rocks, shells, or stones to lay their eggs. The eggs are deposited in small, spherical protective capsules, which are stuck together in a sponge-like mass. Each capsule can contain up to 2,700 eggs, and a single female may produce 80-150 capsules.

The embryos develop within the egg capsules for 2-5 months. During this time, many of the eggs serve as food for the developing embryos, with only about 1% successfully developing into juveniles. After 4-5 months, fully formed juvenile whelks hatch from the capsules in winter. Newly hatched whelks measure about 3 mm in shell length. They then grow slowly, reaching 10-15 mm after one year and 21-26 mm at two years. They typically reach sexual maturity between 4.7 and 7.5 years of age, at a shell height of 45-70 mm.

Adult whelks are carnivorous predators and active scavengers. They use chemosensors to detect food in the water, extending a tube called a siphon to funnel water into their sensory organs. Their diet includes polychaete worms, small bivalve molluscs, and carrion. Common whelks typically live for about 10 years.

Unless, of course, they are caught for eating by carnivorous humans.

Brighton & Newhaven Fish Sales operate several boats that catch whelk (among other fish). The Evie Mae, an under-10m multipurpose catamaran, engages in whelk fishing during the warm summer months. One of its fishermen, Kier Foster, was quoted recently as saying: ‘There’s not much of a market here for these [local catches]. It’s best to cook the whelks, slice them up and send them to China where they go for £30 a kilo.” 

Nevertheless, you can buy fresh whelks on Brighton’s pebbles in the summer thanks to Frazer Leigh Smith’s Brighton Shellfish & Oyster Bar where they are served with vinegar and pepper. Delicious - if you like the sort of thing!

Of cockles clams and scallops

There seem to be an unusually large number of shells (the exoskeletons of animals) on the beach this winter. I may be wrong but I don’t recall shells vying with pebbles for dominance in so many areas along the tide line - perhaps this is because of a preponderance of winter storms and rough seas.

Here’s a photo from today with some or all of the following: 

Common whelk (Buccinum undatum) - spiral shells

Mussels (Mytilus edulis) - darker, elongated shells

Cockles (Cerastoderma edule) - rounded shells with ridges

Venus shells - smoother, rounded shells

Barnacles or limpets - possibly some of the encrusted or broken parts

The largest shells that I’ve ever found on Brighton Beach are scallops, beautiful fan-shaped objects. There aren’t many, though, because most of them, the ones I’ve seen and collected over the years, have been found much closer to Shoreham, immediately east of the River Adur (near the fab cafe, Carats).

Fun fact from BBC Science Focus. The very largest shells are of giant clams, Tridacna gigas. They can grow to well over a metre across and tip the scales at 200kg. Like all shell-making molluscs, they sculpt their protective homes from calcium carbonate and gradually expand them throughout their lives. They inhabit coral reefs and can live for at least a century. Here’s one on sale for around £3,000 (by UK Architectural Heritage).

Coming soon - life cycle of the common whelk!