“We feel useful. Today we are fishing, our passion, while contributing to a scientific project to preserve sharks.” On the water Saturday, September 7 at noon, in the harbor of Brest, Victor, Yann and Sowen, young people from Brest, have just collected a spotted shad on their boat and are taking the day’s mission very seriously. They carefully collect information on the fish (measurement, weight, sex, fishing area, time of capture) and mark it (placing an external mark on the fin, with a unique number) before releasing it.
The tag is placed on the shark’s fin using pliers. All year round, a marking kit is provided by Apecs to recreational fishermen who wish to get involved in scientific research by marking the emissoles. (Le Télégramme/Chloé Ragueneau)
Mustelus, a species almost threatened with extinction
The “emissole challenge” is in fact organized that day by Apecs (Association for the study and conservation of selachians). The 36 participants, divided into 16 teams (five in kayaks and eleven in boats), set off early in the morning from the Térénez marina in Rosnoën.
Each team aims to mark as many emissoles (scientific name: Mustelus) as possible. “Our project, dating from 2018 and called “Mustelus”, aims to mark as many emissoles as possible in different areas of French waters. Since 2021, we have also been encouraging recreational fishermen and fishing guides trained by the association to mark emissoles independently. We distribute marking kits to them,” explains Alexandra Rohr, project manager at the Brest association.
“This is the first challenge we are organising. We want to continue to raise awareness about this species that is almost threatened with extinction. Tagging sharks aims to ensure that when they are recaptured, we have, for example, new information on their location, to understand their movements. We are working closely with Ifremer and unfortunately we have too little data on the biology and ecology of most sharks.”
303 emissions marked in one day
Although the movements, structure and size of the populations of emissoles are poorly understood, the Apecs team has noticed their large numbers in the harbor: “Their gatherings there seem to be rather seasonal. We are a priori in the presence of pregnant females. Their marking in this area is used in particular to understand whether they stay here all year round, and to ensure that they are females. We think that they stay in the area because it is a sheltered place with food available. We wonder if they give birth here. We need to mark as many of them as possible because their recapture percentage is 5%…”.
Since 2021, the Mustelus mission has enabled the tagging of 781 emissoles in the harbor of Brest, of which only 21 have since been recaptured. This is without counting the 303 emissoles that were tagged on September 7 in the harbor during the challenge. The winning team, made up of two fishermen, will have tagged around forty of them.
The emissole, the shark that seems to be the most common in Brest harbor, also shares these waters with others of its species, such as the Hâ shark, the basking shark, the blue shark and the small and large dogfish.
