Blog post

Identification of species

Published on
September 4, 2012

After some time sorting catches, we forget how difficult it can be for newcomers to distinguish fish or other species.

Starting with a new crew, we again realised that species identification is a process. First of all, it helps when you know how many look-alike species you can expect. If, for example, you are not aware of the existence of more than one swimming crab species, you might not even think about looking good to the specimens in your hand as you assume there’s only one species to deal with. As soon as you know there might be more than one species, your eyes get trained and you can start looking for differences. It also helps when you know what to look at. It’s learning by doing, and it helps to have a look in some identification guides now and then, as Margot and Janna do on the picture. To improve identification quality and to check the identification skills of IMARES personnel, we organise an annual identification test and workshop.

The picture below shows three different flatfish species, from left to right: American plaice (Hippoglossoides platessoides), Scaldfish (Arnoglossus laterna), and Megrim (Lepidorhombus whiffiagonis). We caught them all in one haul. In flatfish species one of the main characteristics is the side of the eyes. In American plaice they are on a different side than in the other two species. Looking further, Scaldfish easily looses its scales, while the other two species don’t.