Rich is the Mermaid’s Purse
Rich is the Mermaid’s Purse
Yesterday, I took a stroll along Whitestown Beach, Cooley
Post-storm beaches are always most bountiful. In Whitestown, where the Cooley peninsula points southeast towards Wales into the Irish Sea, I took a stroll to see what I could find. There was plenty of marine litter (fishing nets, bottles, wrappers) among the freshly flung seaweed along the strand line. Storm Isha and Jocelyn carved out large depressions which undulate along the beach from powerful destructive waves.
When I walk strand lines I am always on the look out for shark and skate egg cases, called mermaids purses in English and sparán na caillí mairbhe (the dead hags purses) in Gaeilge. Many shark and skate species in Irish waters lay egg cases wherein the embryo develops. Each species has a unique egg case and by surveying what egg cases we find on the beach, we can extrapolate what species are activity breeding in the waters just off the shore.
On my casual survey along Whitestown beach, I collected 17 egg cases of the small-spotted catshark (Scyliorhinus canicula), called catsúileach ballach (catsúileach = cat-eyed, ballach = a spotted fish) in Gaeilge. They are also called dogfish, rough hound and fay dog in English. They are our most common shark species and are often encountered alive when diving, and dead on the beach. Their egg cases have long twisting tendrils which attach to seaweed to prevent them being washed away by currents. Once they have evacuated the egg case, the cases are free to be washed on to the strand.
There is something almost magical about finding the remnants of a creature without seeing the creature itself; an egg case, a footprint, a feather. It serves as a proxy, or an indirect way to find out what is breeding in our waters. I will continue to survey local beaches around Carlingford Loch in order to paint a more detailed picture of shark and skate biodiversity. There is the citizen science project called the Great Eggcase Hunt run by The Shark Trust which has a wealth of knowledge, and a portal to submit findings of egg cases.
