Some sharks, skates and rays reproduce by laying tough leathery egg capsules in which the embryo develops. They spend several months under water until the pup is ready to hatch. These egg cases are often found washed up on the beach and are colloquially known as mermaid’s purses.
By looking at the colour, size and shape we can tell which type of shark, ray or skate produced them and as a result this is a good indicator of what species are breeding nearby – there are over 30 species of shark in British waters.
This is the perfect time to get down to the beach and check out what you can find, not only is there a ready-made egg-hunt but the weather is likely to make those strandline searches all the more profitable.
Here are some examples of things we’ve found (for the egg cases of each, see the chart below):
- The Small Spotted Catshark is a small shark and so named due to the dark blotches on its skin. This shark feeds on crabs, molluscs and other small fish. These egg cases are commonly found along the Sussex coastline, tangled up in other marine debris, they blend in with the pebbles though so keep your eyes peeled. © Olle Åkesson
- The most common ray in the British Isles the Thornback Ray, so called due to the spines on its back. Will often bury itself in sediment during the day and come out to hunt for crustaceans at dusk. The Thornback Ray is listed as Near Threatened on the IUCN Red List. ©Paul Naylor
- Nursehound, also known as a bull huss (and a lot of other names too) are a larger catshark, known for playing hide and seek in rock crevices, they stay close to the sea floor and love themselves a midnight feast (they’re nocturnal). Snacking typically on cephalopods, crustaceans and small fish. This egg case is a little rarer around here so bonus points if you find it.
Other commonly found egg cases along the Sussex coast include Undulate and Spotted Ray, make sure to consult the guide below thoroughly though as these can get mixed up.
We’ve created this amazing Go Explore guide to help families make the most of their time at the coast, from fossil hunts to coastal walks, you can download the pdf here
Make sure to record everything you find with our colleagues over at the Shark’s Trust, they’ve even got a handy identification guide with a lot more detail. And please write ‘Wild Coast Sussex’ in the organisation box.