The narwal shrimp (Plesionika narval) is one of the best delicacies the sea con offer. Oh well, maybe it’s weird starting like this, but it’s undeniable! That’s why it’s massively commercialized in the Canary Islands and in Madeira (north-east Atlantic) and seldom in the Med, although it is known in the Red Sea and the Indo-Pacific (Madagascar, Polynesia) as well. In the Italian seas the one from Cracolla, in the Sorrento peninsula, is for instance well known, but no less than the one from Ustica.
First of all the narwal shrimp is a decapod crustacean. This means it has five pairs (hence ten) of feet, so to speak, called pereopods, plus other appendices not used for locomotion though. It is a rose-orange shrimp with longitudinal red and white stripes, a sharp rostrum (which is why its scientific name is narval, whence comes the narwhal, the cetacean with a long tusk) with plenty of tiny teeth, and two pairs of long white antennae. It is tiny, not longer than 10 cm, and it lives from just a few meters under the surface until at least 900. It usually fancies muddy bottoms, but as scuba divers we’re mostly interested in its taste for caves, caverns and dark places in general, where it lives even at shallow depths and always in schools of hundreds or thousands of individuals. This is the reason why almost everywhere along the Italian Coast there is a Shrimp Cave whose shrimps are indeed the narwals.
Its biology has a couple of interesting features. First of all the females are more numerous and slightly larger than the males, and then they are always pregnant! Yes, because the reproduction of the narwal shrimp happens all year round, although with a preference for the warmer water in summer and autumn. Indeed, when we spot them while diving we will always recognize the females from those microscopic electric blue spheres they bear under the pleopods (other paws right behind the pereopods), that is, the eggs!
Along our itineraries the most famous Shrimp Cave is probably the one in Ustica; yet there is one in Filicudi, Castellammare, even in Linosa’s dive site Secchitella… Well, narwal shrimps are almost everywhere and always a great show to see, especially when a hungry forkbeard (Phycis phycis), a comber (Serranus cabrilla) or a conger eel (Conger conger) take advantage of our diving lights to gulp down a handful of them!
But remember, only in Ustica, as far as we know, the narwal shrimp is fished and eaten regularly and rigorously raw, “unpeeled”, and seasoned just with olive oil and lemon…