Did you know mermaid purses are often mistaken for seaweed on beaches? It’s true! In this blog post, we will be looking at Mermaid Purses: oh, sorry - we mean the egg sacs that are used to help baby sharks hatch! There are no dinglehoppers in these bags - just baby sharks, rays, or skates!
What Are Mermaid Purses?
Mermaid Purses are tough, leathery pouches that protect developing shark embryos! While most sharks and rays give birth like humans, with live pups or babies, some sharks and skates lay eggs which are surrounded by this tough casing! Skates are a type of stingray - known for being a little more diamond shaped and not actually having stingers! Did you know that sharks and rays are very closely related? It’s true! And the Mermaid Purse helps prove it. Scientists often use the found discarded egg cases to find where the breeding grounds of certain shark and ray species are!
Take a closer look at mermaid's purses
Image Credit Peppermint Narwhal on Twitter: @PepomintNarwhal
What Does a Mermaid Purse Look Like?
Mermaid Purses are most commonly sighted on shore, empty and now black or brown thanks to the lack of nutrients. They tend to be confused with washed up seaweed. The pods look a little like air bladders of seaweed. They are leathery to the touch and most often have two or four tendrils hanging from one end of it. These tendrils can be curled or look spikey - the shape and size helps scientists determine which species hatched from the case!
Where to find a Mermaid Purse?
Mermaid Purses often wash up on shores, the sack is thick enough that even after the babies are hatched from it, they can drift along the currents! They are often spotted on beaches as a small black thing - like a jellyfish or a piece of seaweed. However, on closer inspection you’ll see that they tend to have tendrils having off them, and look more like a bag than anything else - hence the name! They are often seen washed up with seaweed and grass because they are attached to the plant while they protect the embryo!
The best time to spot Mermaid Purses are after large storms or large currents. The more seaweed on the shore, the more likely you are to find a mermaid purse! When beachcombing, check the high tide line!
Sometimes you may even find a mermaid purse with a live embryo inside it! This is very rare and is really only seen after a super bad storm. If the purse is open, there is no live embryo in the sack. Only at the very young stages of development can an embryo survive in a fully sealed purse outside of water - after their lungs develop they will need the filtered oxygen of salt water to live. Like we said - it’s super rare! If you ever are this lucky and are certain there is a baby fish inside, carefully take the sack back into the water - away from the surf, below the shoreline, and tidal zones if possible!
Can you Keep A Mermaid Purse?
You can! These little sacks are tough little fellas, and with the right measures it can stay dry and intact for many years. The first step is to make absolutely sure it is completely empty. The fish are decomposed and gone, and nothing else has tried to make a home inside! Once sure, we recommend finding a place where the sun can completely dry it. The best way to care for the mermaid purse is to keep it clean and dry. Then it can be placed inside a reusable bag or container. Keeping it dry and clean will help ensure it stays its tough bagged self for many years!
If you’re ever feeling creative enough, these purses can be made into necklaces! You can see a few examples on sites like Etsy. Check this really cute one out here! It’s also a really great idea to report if you find one to the local research centers! Like mentioned prior, scientists can use their location to update fishing laws and help protect breeding grounds!
What Comes Out of a Mermaid Purse?
There are many species that can come out of a Mermaid Purse! Almost 25% of shark species actually give birth via these egg sacs instead of giving a live birth! Some notable sharks are the catshark, the lesser spotted Dogshark, and the Bullhead sharks! Notably, the Bullhead sharks lay sacks that look a little rougher, with a cool spiral shape!
A big difference from rays and skates is how all skates give birth via the mermaid purses, and most stingrays have live pups! Many aquariums display mermaid purses with nurseries, check out this awesome video taken at the Galway Atlantaquaria in Ireland!
The Mystery of the Mermaid Purse
While no real mermaids use these bags to help carry their items around, they serve their purpose carrying the young of the sea! They are definitely one of the coolest ways life evolves in the ocean. To learn more, we recommend this article from Marine Dimensions!