The speckled seahorses of the Thau pond: a conference to discover this fascinating species of lagoon fish

La chercheuse Laura Meyer avec un hippocampe séché dans son laboratoire de l'ISEM Photo transmise par Laura Meyer

La biologiste marine Laura Meyer a étudié les particularités de l'hippocampe de l'étang de Thau et donne une conférence à ce sujet, ce jeudi 22 février, dans le cadre de Sèt'Expo Sciences.  

We knew that the Thau pond was a haven for seahorses. What was less known was that these fascinating lagoon fish differed genetically from their marine counterparts. This is what Laura Meyer, marine biologist and postdoctoral researcher at the Montpellier Institute of Evolutionary Sciences (ISEM), tells us. 

Why were you interested in seahorses ? 

A previous study showed that the speckled seahorse (Hippocampus guttulatus) has a particular genetic structure. In the Mediterranean, this species is subdivided into two lineages – one lineage which is present in lagoon environments and the other in the sea. As my thesis project aimed to study coastal fishes presenting marine lineages and lagoon (called ecotypes), I included the seahorse in my analyses. 

How are the seahorses of the Etang de Thau special ?

In terms of appearance, no study has formally found morphological differences between lagoon and sea seahorses. However, lagoon seahorses are genetically differentiated from their fellow sailors. The Thau pond is a good example, hosting one of the largest populations of lagoon seahorses in the Mediterranean, with the presence of marine seahorses just on the other side of the pond. Lido de Sète. 

What were your methods for conducting this study ?

To study the genetic structure of a species, we extract the DNA from several individuals and sequence it so that we can compare them. In particular, we were able to extract DNA from dried seahorses to avoid having to fish them. These were given to us by citizens in a participatory science approach, following an announcement in the Midi Libre.

Conference

Proposed by Sèt'Expo Sciences and hosted by Laura Meyer, the conference on the seahorses of the Etang de Thau will take place Thursday February 22 at 6:30 p.m. in the Victor Meyer room in Sète , 11 Rue du Moulin à Vent.