Where to find mermaid purses

The high tide line is easily identified by the long bands of dried seaweed that stretch across a beach. It is actually amongst the seaweed where you are most likely to find a purse, but you have to look closely because the dried out cases look very much like the seaweed they are surrounded by.

If you have no luck at the high tide line, then the next best place to look is in rock pools, because they can often get trapped in them as the tide goes out. Whilst there is a clearly defined shape and structure to most egg cases there is also a large variety of different sizes, types and variations between species, much like how different birds lay their own unique eggs.

For catsharks the pouch will tend to be more rounded and have long spindly tendrils, which can often get wrapped around in seaweed or other egg cases. For skates the pouches tend to be more rectangular and have defined horns in place of tendrils. A more bizarre example is chimaeras who produce bottle-shaped pouches with a pair of feathery fins down its sides or the bullhead sharks who produce spiral auger-shaped egg cases designed to get wedged into crevices between rocks.

However it is unlikely you will find these more bizarre designs, especially on your first try. So how do you figure out which species has produce the egg case you have found?

One of the big problems with identification is that purses you find on the beach are dried out and so often misshaped or decoloured. Therefore the best way to make a successful identification is to take it home and re-hydrate it. You can do this by placing it in a bowl of water, preferably from the sea, for a couple of hours. You will notice that it will change shape, get darker and will feel more slimy if you touch it. At this point you might also be able to find the opening the juvenile shark or skate swam out of when it was fully developed.

Now you have a re-hydrate eggcase you will be able to determine more details about the shape, size, colour and any other features you need to make a successful ID. For the best results use online guides like this awesome one by Marine Dimensions and you will then know for sure what you have found. Egg cases provide clues as to where certain species of shark or skates can be found, especially the nursery grounds that are important for juveniles.

This information can then be used to help inform conservation measures to help protect sharks and rays across the world. Citizen science projects involving egg cases can be found across the world online. The baby shark or skate then hatches out of the purse and swims away, leaving the discarded eggcase behind it.

If you have seen an eggcase, you could help to make a difference for vulnerable species by reporting your sighting to your local citizen science sightings scheme. Your sighting could help to gather crucial information necessary for fisheries conservation management. However, on closer inspection you will see that the pod has distinctive spikes or curly tendrils at either end of the capsule.

We can use the shape and size of these features to determine which fish species has laid the egg. Square or rectangular purses with spikes at either end are generally laid by skates and rays.

Tubular eggcases with curly tendrils at either end are usually laid by catshark species. The female uses these strings to attach the purse to seaweed in the shark nursery area. You can see the babies wiggling their tails to replenish the oxygen in their purses.

The embryo develops from the egg in its purse obtaining nourishment from the yolk sac as it develops. The time spent in the egg by the embryo depends on the species. Some, like the rare and critically endangered White Skate, may stay in the pod for as long as 15 months! Other species may be ready to hatch after a few months. All species remain in the purse until the baby is ready to live life independently in the ocean without any care from its parents.

When the baby shark or ray is hatching, it squeezes out of the top of the eggcase through a narrow slit between the horns or tendrils. This opening may be difficult to see if you find the purse on the seashore when it has already dried out. Create a personalised content profile. Measure ad performance. Select basic ads. Create a personalised ads profile. Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors.

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