A mermaid’s purse

A mermaid's purseLast week as the tide came in, a number of mermaid’s purses were washed up on the shore at Frinton-on-Sea in Essex. This is one that I picked out of the sea (and swiftly returned). Caught up in the seaweed, they were sometimes hard to spot amongst the other dark rubbery tubes. Others were bobbing about on the surf so they were easy to scoop up from the water.

A mermaid’s purse is actually the egg case of a skate, a ray or a shark, especially dogfish.  Usually, there is only a single animal inside each egg case, although some species can lay eggs with up to seven animals in a single brood.

Some of the egg cases were torn and frayed where their occupants had wriggled their way out into the water. These were dry and crispy to the touch. Others  had a smooth glossy finish with a slight rubbery feel . At first, I thought that these still contained an embryonic fish, but I later learned that the shells only get washed up on the beaches once the fish have already hatched.

Another mermaid's purse

After my discovery, I then went online to discover what animals may have laid these eggs. Luckily, there is already a research project in the UK to record and classify all these findings. It’s called The Great Eggcase Hunt Project and it’s run by the Shark Trust. I submitted my photos to their website and they replied to me the same day, despite the fact that mine was just one of 53,700 sightings that they have received. Cat Gordon, a conservation office at the Trust was able to inform me that these were from a thornback ray, and not from a mermaid at all.