Mermaid's purses are, in-fact, eggcases produced by sharks!
As well as being places of natural beauty, our beaches hide real treasure troves...if only you know where to look! We are talking, of course, about mermaid's purses. Unlike the name would suggest, mermaid's purses are not, unfortunately, the bags carried around by musical mythological creatures. The truth, however, of what lies within is far more exciting!
What are mermaid's purses?
Mermaid's purses are, in-fact, eggcases produced by sharks (yes, you read that correct - sharks!). Some sharks and all true skates reproduce by laying eggs. These eggs are surrounded by a tough, leathery pouch, which protects the growing embryo as it develops (similar to a chicken egg, but far more durable!). The pouch is made out of collagen/keratin, the same as hair and fingernails!
Image: An occupied small spotted catshark eggcase © NWWT
How do mermaid's purses end up on our beaches?
After several months, a fully formed shark or skate will emerge from the egg, leaving the eggcase behind. It is at this point that the eggcases, or mermaid's purses, often wash up, empty, on our beaches. Generally, as happens with most material washed up from the ocean, eggcases find their way to the strandline where they mix with seaweeds, natural debris and, all too often, plastics.
*Please note* if you do find an eggcase which is still occupied do not remove it from the beach. Place back in the water where possible!
What do different species mermaid's purses look like?
Although identifiable directly at the beach, the best way to ID your finds is to rehydrate them first. This allows you to see just how large the eggcases would have originally been! Fill a bucket with fresh water, and place your eggcases inside for 1 - 2 hours. Once soaked, you can remove your mermaid's purses from the bucket, and start your detective work!
The simplest level of ID involves determining if your eggcase belonged to a shark or a skate:
• Catshark eggcases have long curly tendrils at each end, which can often become tanged with other cases.
• Skate eggcases are more rectangular in shape than the above, and also have a horn which extends from each corner.
What can I do from home?
For the time being there are various egg-related things you can still get up to from the comfort of your own home:
• Colouring: Why not embrace your inner eggsplorer, and add some colour to an undulate ray, small spotted catfish, and so much more!
• Memories: Do you or your family have memories about sharks around the Welsh coast? Perhaps you swam with Basking sharks as a child? Submit your marine memory here.