Mermaid’s Purse: Egg Case for a Shark, Skate or Ray

Subject: Bug/Creature?
Location: Seaside Heights, NJ beach
August 1, 2016 4:55 pm
found a bunch of these washed up on shore from the ocean and was wondering what they are…
Signature: Karen

Dear Karen,
This is a Mermaid’s Purse, the egg case of a shark, skate or ray.  According to About Education:  “Perhaps you’ve found a “mermaid’s purse” on the beach. These mermaid’s purses blend in really well with seaweed, so you may also have walked right by one.   The enchantingly-named structures are the egg cases of skates and some sharks. While some sharks bear live young, some sharks (and all skates) release their embryos in leathery egg cases that have horns and sometimes long tendrils at each corner. The tendrils allow them to anchor to seaweeds or other substrates. Each egg case contains one embryo. The case is made up of a material that is a combination of collagen and keratin, so a dried egg case feels similar to a fingernail. ”  According to British Marine Life Study Society:  “Regular rockpoolers are likely to have come across ‘Mermaid’s Purses’, containing the eggs or young of the Lesser-spotted Dogfish, Scyliorhinus canicula, lying amongst the debris on the tideline. These egg capsules that have been dislodged after being laid by the adult female dogfish are doomed to perish. Some, if not most, of the capsules are empty. However, on many occasions I have found a live embryo inside, some of them nearly ready to break free from the capsule. ”  According to Shark Trust:  “Each eggcase contains one embryo which will develop over several months into a miniature shark, skate or ray. Once empty, the eggcases often wash ashore and can be found among the strandline on beaches.”