Close encounter of the weird kind

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Free diving to the tugboat. One of Accretio's group leaders shows how it's done...

Free diving to the tugboat. One of Accretio’s group leaders shows how it’s done…

With a big splash we all dove head first into the sea. Mission for the day: exploring the underwater area in which a small tugboat went down several decades ago. This spot along the south-eastern coastline of Caracasbay, Curaçao, is one of the more popular snorkel and dive sites on the Island. Perfect for an exploratory expedition with the kids from Accretio, the rebound facility I am working with on a structural basis.

Suddenly, a wide-eyed and exited kid approached me, splashing and gesturing: “look, a weird thing in the water! Is it dangerous?” I swam over to the indicated spot, and encountered something that was quite new to me. A transparent gelatinous hose-like ‘thing’ of about 1.5 meters long and 25 centimeters wide. The outer surface looked like a tightly coiled-up string of small purple beads. Thousands of them. “Better safe than sorry, guys. Don’t touch. I have no idea what it might be, but let’s not rule out that it might be some sort of jellyfish”.

I filmed the ‘thing’ (see below), and we let it be.

Thysanoteuthis rhombus. Historical drawing by Comingio Merculiano (1845–1915) in Jatta Giuseppe.

Thysanoteuthis rhombus. Historical drawing by Comingio Merculiano (1845–1915) in Jatta Giuseppe.

Later on, being as inquisitive as I am forcing myself to be, I searched the literature in our library in order to put a name on the ‘thing’, but to no avail. Indeed, several species of ribbon-like Cnidarians do exist, but not one of these looks like what we found.
And then I encountered an obscure web site. Someone else found exactly the same thing we did, and posted the same question we had: what is it? Answer: …. it might be an egg-mass! With this new insight I changed the search algorithm and quickly found the amazing answer to the riddle: indeed, the ‘thing’ proved to be the egg mass of an oceanic squid, the diamondback squid, or Thysanoteuthis rhombus. This species occurs worldwide in tropical and subtropical waters, and might reach a length of about 1 meter, and a weight of about 25 kilograms.
All the little purple beads are separate eggs, in which minute squids are developing themselves. Had I known that at the time of the encounter, I would have taken an even better look. Clearly this egg-mass posed no danger to us, rather the other way around. Maybe it is a good thing this beautiful egg mass looks like something venomous. That way the baby squid might have a better chance of growing into adulthood!

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