A few weeks ago, on a Monday afternoon in mid-November, a local was walking along Bray seafront in Wicklow. The calm after Storm Claudia had left the beach whipped up, and something unusual caught her eye on the higher part of the shoreline: a leathery pouch-like object about the size of a chocolate bar, with tendrils at each corner.
She had an inkling it was something special, so she brought it to the recently opened Marine Life Aquarium in Bray, the only public aquarium on Ireland’s east coast. The staff realised it was significant, so they sent a photo of it to fisheries expert Dr Kevin Flannery, founder of Dingle Oceanworld Aquarium. Flannery could hardly believe what he saw: what on Earth was a flapper skate egg doing in the Irish Sea, a place where the species had long gone all but extinct? In all his years, he’d never seen anything like it. To find one in the Irish Sea was a stroke of improbable luck, like seeing a corncrake in a school garden in the middle of Cork city - technically possible, but so astonishingly rare you’d think nature was playing a trick on you.
Flannery wasn’t alone in his astonishment. He texted marine biologist Dr Patrick Collins at Queens University Belfast, who replied with equal incredulity: “Holy God. How did you get that?” Collins, an international expert on skates, was gobsmacked. Could the presence of a flapper skate egg in the Irish Sea be a hint that the species is slowly recovering?
The find is extraordinary. A century ago, an egg on a Bray seafront would have gone unnoticed - flapper skates were abundant in Irish waters. At that time, they were recorded as “common skate” in scientific surveys; it wasn’t until 2010 that researchers distinguished the larger flapper skate from its smaller relative. Today, their numbers are vanishingly small, with only a handful occasionally spotted off the coast of Kerry - never in the Irish Sea.
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Flapper skates never stood a chance against industrial fishing, which intensified in the 1970s. Their slow lifecycle made them highly vulnerable to the repetitive, intense efforts of commercial trawling and dredging. For one, they’re large and slow-moving, making them easy enough to catch. An adult flapper skate, reaching up to 2.5 metres in length, resembles a diamond-shaped kite gliding just above the seabed, its brownish-grey rough skin camouflaging it against the sand and gravel below.
They take an age to reproduce. Males might be up to 13 years old before they breed, while females often wait 20 years or more. During mating, the males use claspers to deliver sperm into the female and she then lays eggs in a leathery “mermaid’s purse” on the seabed, and inside this leathery self-contained world the embryo grows for 18 months. But it faces immense threats: a single sweep of a bottom trawl or dredge can crush it, and it’s vulnerable to predation and extreme storms that churn up the seabed. It’s a wonder any of them survive.
Why would a flapper skate egg turn up on Bray seafront? For scientists such as Collins, the answer might lie far to the north, off the Isle of Skye in Scotland, in a marine area called Red Rocks and Longay. About the same size as Phoenix Park, this seabed habitat was found to host flapper skate eggs in 2019. By 2021, the Scottish government granted it urgent legal protection, banning fishing and other disruptive activities.
Female flapper skates don’t lay their eggs randomly. They’ve evolved to choose specific, reliable locations favoured by other females, returning each year to sites that offer the safety and stability embryos need to successfully grow. These spots where the eggs are laid, like the one discovered in Scotland, are tiny - about the footprint of a house. But how do females swimming across vast stretches of sea hone in on the exact spots where others have laid their eggs?
Flapper skates have minuscule, flask-shaped sensory organs on their heads, called “ampullae of Lorenzini”, which detect electric fields in the water - acting as a kind of biological mobile phone. Fascinatingly, they also have a jelly-like organ in their tails that sends out signals. One hypothesis is that as embryos develop inside their cases, they emit increasingly strong electrical signals. Adult females could pick up these cues, effectively thinking “aha! This is a good spot because other eggs are thriving here”, and then laying their eggs alongside them.
For Collins, discovering these nursery grounds is the Holy Grail. There is no evidence of a viable population in the Irish Sea, but because scientists had long assumed the population was, in Collins’s words, “kaput”, nobody has been looking. Could it be that, now that Red Rocks and Longay is protected, more eggs are surviving, and the one that washed up in Bray is the result? It’s a tantalising prospect: that the Irish Sea is benefiting from an overspill from marine protected areas in other jurisdictions.
[ You can’t choose the times you live in. And sadly we live in an age of extinctionOpens in new window ]
With this in mind, Collins and Flannery rely on all of us to report any potential sightings. So if you’re out for a sea walk or swim and spot an object that could be a flapper skate’s egg, let Collins know: patrick.collins@qub.ac.uk.
