A few weeks back a pal sent a photo of these Mermaids’ Purses, also known as Devils’ Purses, that he found on a beach in Cork. He knew the smallest one was from a Dogfish and the largest one was from a Skate or Ray but he wasn’t sure about the middle one so he decided to ask me as I am an expert (ahem)…at least I have been masquerading under the name ‘The Mermaids Purse’ for some time now-so to maintain the illusion of experthood I had to hastily brush up my knowledge.
Mermaids’ Purses are so called because sailors, a necessarily superstitious bunch in view of their perilous and unpredictable lifestyle, often saw Mermaids as portents of impending doom and welcomed any warning of a Mermaids’ presence in an area as an opportunity to wallow in paranoia. They aren’t actually Mermaids’ Purses of course (throws salt over her shoulder), merely egg cases from the Shark family which includes Dogfish, Skate & Ray. The cases are made from collagen, a protein, which can take years to break down. I wish my car was made of collagen…
The egg cases, are attached carefully (according to one source) to seaweed. This must be hard to do without fingers, mind you as spiders can spin traps from their bottoms, I don’t suppose we should be surprised at what nature can do. The young (dogfish or skates, not spiders) can take up to 15 months to develop. Once they leave the egg, the cases then get washed onshore. Sometimes the lazier Shark/Skate babies are still inside, because…
‘Like, birth, you know, whatevs.’
However not all of the Shark family lay eggs. Rays, as it turns out, don’t produce purses at all as they keep their money in their back pants pocket. The Basking Shark, the Porbeagle, Thresher, Tope & Blue Shark, all found in Irish waters also give birth to live young. (That said, the Basking Shark is still quite a mystery in this regard as a pregnant Basking Shark has only been recorded once and then she claimed she’d just been drinking lots of beer). Dogfish & Skates however, are oviparous:they lay eggs.
There are two types of Dogfish found in Irish waters. These guys (well, girls) produce the small, girly purses with the curly tendrils at each corner. They vary in colour from pale gold to nearly black, depending on whether Mammys’ been at the Guinness. The smaller ones, around 60mm, which in my experience are by far the most common, certainly here in the south east, belong to the Lesser Spotted Dogfish. The larger ones (around 100-120mm) are not pictured and belong to the Greater Spotted Dogfish, or Nursehound. They are both, strangely, a species of Catshark. Both can be often be found night-clubbing, tendrils bouncing, wearing short, too-tight, sparkly dresses. The Lesser Spotted Dogfish do better with the boys but that’s not saying much.
The other purses found on our shores are larger, darker and more rectangular or square and are without the curly bits, or any of that carry on, and they belong to Skates. Skates are more likely to be found in church or sitting on park benches staring disapprovingly at Dogfish and are not to be confused with Roller Skates who are generally quite relaxed. There are a number of Skates in Irish waters. The largest purse in the top picture here, at about 160mm, the one minus the horns, is most likely to belong to the Common Skate which are critically endangered, ironically, as they have been drastically overfished and mature so slowly. A bit like me except I don’t have a big purse as I don’t have anything to put in it.
The medium sized purse in the picture (60mm minus the horns)probably belongs to the Spotted Skate as quite neat. The Blonde Skate, also known as a Blonde Ray, though it is actually a Skate, and the unfortunately named Small Eyed Skate have similar purses but with untidier edges. The Small Eyed Skates‘ purse is a little wider at one end than the other. The Small Eyed Skate is jealous of the Blonde Skate. The Thornback Skate, or Ray, again technically a Skate (keep up!), has a similar purse to the Spotted Skate but is a little squatter, its horns being shorter. It doesn’t give a damn what anyone thinks and is jealous of no one. The information here is by no means definitive and identifying which purse belongs to whom can be tricky, especially as fish don’t often carry I.D., but it should help you out if you do find purses when you’re out and about on the beach. They are most common between November & July.
Here is the bit where you can get involved with very little effort. Purse Search Ireland was launched in 2007 in an effort to get the public to record any purses found. As with the reporting of whales & dolphins, this information can give us an idea how these species are doing, allowing conservation efforts to be focused where most needed. I contacted the leader of the project, Dr. Sarah Varian, yesterday to confirm that this project is ongoing and she has told me that the project is ongoing and currently being revitalised and she would be delighted to receive any reports. The link just below will bring you to a recording form. You can fill out a description, take photos or even mail a sample in.
If you are the UK check out The Great Eggcase Hunt
Note:All of the information here is as accurate as I can make it except for the bits where I fibbed for cheap laughs. Work out which bits those are for yourself.
Illustrations are available from my Etsy Shop here…feel free to browse.
Further Reading & References
Bassett, F. S., (1885), Legends and Superstitions of the Sea and of Sailors in all Lands and at all Times(extract), [online], available at http://www.alternatewars.com/Mythology/Legends_Super_Sea/Legends_Superstitions_Sea_Extract.htm [accessed 20/04/2017].
Callinor, H., et al, (1999), A Beginners Guide to the Irish Seashore, Cork:Sherkin Island Marine Station
Natural History of Sligo & Leitrim, (2015), Mermaids’ Purses, [online], available at, http://staffweb.itsligo.ie/staff/dcotton/Mermaids_purses.html
Sherkin Island Marine Station, (2017), Sherkin Island Marine Station (website), available at, http://www.sherkinmarine.ie/ [accessed 20/04/2017].
Tiernan, J. P., (2010), Mermaid’s Purses on our Beaches, in The Mayo News, [online], February 16th, available at, http://www.mayonews.ie/index.php?option=com_content&view=article&id=8965:nature-mermaids-purses-on-our-beaches&catid=50:outdoor-living&Itemid=144 [accessed 20/04/2017].
Varian, S., (2007), Join the Hunt for Mermaids’ Purses, in the Sherkin Comment, [online], issue No.44, available at, http://www.sherkinmarine.ie/SherkinComment44.pdf [accessed 20/04/2017].