Abundances and biological traits of the juveniles salmon sampled in the survey of Salmon abundance Indices in the Scorff river (France)
Citation
Jeannot N, Azam D, Guilloux Y, Prévost E, Marchand F (2024). Abundances and biological traits of the juveniles salmon sampled in the survey of Salmon abundance Indices in the Scorff river (France). Version 1.18. Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE). Occurrence dataset https://doi.org/10.15468/mz4lyw accessed via GBIF.org on 2024-08-14.Description
A survey started in 1993 is conducted every year in early autumn (late September to early October) to quantify the abundance of juvenile Atlantic salmon in the Scorff In Brittany. The electric fishing protocol of Prévost and Baglinière (1995) is used. It targets Atlantic salmon young of the year (0+ parr), but older fish (juvenile salmon ≥1+) are also caught and included in this dataset. Sampling is restricted to areas with shallow running water flowing on coarse bottom substrate, i.e. the preferred habitat of young of the year salmon. The data consist of abundance indices and biological traits measured on the fish sampled: sex, maturity status, length, weight and age. The latter is ascertained from scale samples taken from the fish which size does not allow to determine their age unambiguously. The survey is carried out under the Research Observatory on Diadromes Fishes in Coastal Streamss (ERO DiaPFC) program. The data are stored in the database of the ERO. They are used to develop predictive models and tools for providing scientific advice to improve the management of this heritage species.Sampling Description
Study Extent
Scorff river, CdSandre=J5--0220 Latitude between 47.7718 and 48.1682; longitude between -3.2497 and -3.3404 Source latitude and longitude : 48.14 -3.283 Last confluence point latitude and longitude : 47.7371 -3.3474 The Scorff river is a small coastal stream of Southern Brittany (France). The main river is 78,6 Km long including 15 km of estuary. The mean gradient is 3,6%, the annual mean discharge is 5 m3 s- and the drainage basin area is 480 km2. Human activities and land use are mainly from agriculture, with some areas made moors and forests. Atlantic salmon colonization is essentially restricted to the main river over a 50 km stretch starting at the head of tide. Reproduction of Atlantic salmon takes place mostly in the main river (Bagliniere et al., 1979).The Scorff has only three larger tributaries. Up to recent years, their colonization by Atlantic salmon was restricted their down-stream end due to mill-dams.Sampling
In the Scorff, sampling is conducted at 42 sites spread along the mainstem and 27 spread over 12 tributaries in the area of the hydrographic network colonized by Atlantic salmon. The sites are visited once a year at the beginning of autumn (end of September to early October).Method steps
- Juvenile salmon are caught by electrofishing. Until 2021, a 400 Hz pulsed current generator and then a direct current generator were used and the following procedure is followed: 1 Two large dip-nets with metal frames are placed facing the current, lying on the bottom, and kept at a fixed position. : 1. Two large dip-nets with metal frames are placed facing the current, lying on the bottom, and kept at a fixed position. 2. The anode scans an area of about 4-5 m upstream of the dip-nets in the vein of water filtered by them. 3. Fish attracted by the anode and shocked go down into the nets guided by the electrode and driven by the water flow. If necessary, the fish stuck on the bottom or in aquatic vegetation are recovered by a small hand net. 4. Individuals are transferred into a bucket previously filled with water. 5. The whole team moves laterally several meters out of the area that has just been disturbed by the electric field, the carrier of the electrofishing gear taking care of not to step on the area he will next explore with the anode. When a bank is reached, the progression is a few meters upstream. Then steps 1-5 are repeatedThe sampling at a given site stops after 5 minutes of actual fishing – i.e. the duration when the electric field is applied in the water - measured directly on the counter of the electric fishing equipment. Juvenile abundance is quantified by the number of individuals captured for a unit effort (5 minutes of fishing under the conditions specified above). Biometric measurement of the fish are recorded after their anesthesia with benzocaïne. The fish length is measured from the tip of the mouth to the fork of the caudal fin (1 millimeter precision). Fish are then weighed (0.2 g precision) and maturity status is assessed by a gentle pressure on the belly that allows to get sperm in mature males. All the fish sampled are then released in their original site.
- Age is verified from scale reading according to standard methods described by (Baglinière and Le Louarn, 1987) and (Richard and Bagliniere, 1990).
Additional info
This data set is intended to be updated annually.Taxonomic Coverages
-
Salmo salarrank: species
Geographic Coverages
The Scorff, a coastal river in Brittany (France)
Bibliographic Citations
- Prévost E., Baglinière J.-L., 1995. Présentation et premiers éléments de mise au point d'une méthode simple d'évaluation du recrutement en juvéniles de saumon atlantique (Salmo salar) de l'année en eau courante, p. 39-48. In Gascuel D., Durand J.L., Fonteneau A., (Eds.) Les recherches françaises en évaluation quantitative et modélisation des ressources et des systèmes halieutiques. Colloques et séminaires, ORSTOM éditions, Paris. -
- Prévost E., Nihouarn A., 1999. Relation entre indicateur d'abondance de type CPUE et estimation de densité par enlèvements successifs pour les juvéniles de saumon atlantique (Salmo salar L.) de l'année. Bull. Fr. Pêche Piscic., 352 : 19-30. -
- Baglinière, J. L., and Le Louarn, H. 1987. Caractéristiques scalimétriques des principales espèces de poissons d’eau douce de France. Bulletin Français de la Pêche et de la Pisciculture: 1–39. -
- Richard, A., and Bagliniere, J. L. 1990. Description et interprétation des écailles de truites de mer (Salmo trutta L.) de deux rivières de Basse-Normandie : l’Orne et la Touques. Bulletin Français de la Pêche et de la Pisciculture: 239–257. -
- Marchand, F. et al (2017). Abundance indices and biological traits of juvenile salmon (Salmo salar) sampled in three rivers on the Atlantic and Channel coasts (France). Biodiversity Data Journal 5, e15125. -
Contacts
Nicolas Jeannotoriginator
position: Engineer
INRAE U3E, Pôle OFB-INRAE-Agrocampus Ouest-UPPA pour la gestion des migrateurs amphihalins dans leur environnement
Moulin des Princes
Pont-Scorff
56620
FR
Telephone: +33297325429
email: Nicolas.jeannot@inrae.fr
Didier Azam
originator
position: Engineer
INRAE U3E, Pôle OFB-INRAE-Agrocampus Ouest-UPPA pour la gestion des migrateurs amphihalins dans leur environnement
65 rue de St Brieuc, CS 84215
Rennes
35042
FR
Telephone: +33223485786
email: Didier.Azam@inrae.fr
Yoann Guilloux
originator
position: Technician
FDPPMA56
Moulin des Princes
Pont-Scorff
56620
FR
Telephone: +33 297325429
email: yoannguilloux.mdp.fedepeche@orange.fr
Etienne Prévost
originator
position: Researcher
INRAE ECOBIOP, Pôle OFB-INRAE-Agrocampus Ouest-UPPA pour la gestion des migrateurs amphihalins dans leur environnement
Aquapôle - Ibarron
St-Pée-sur-Nivelle
64310
FR
Telephone: +33559515983
email: Etienne.Prevost@inrae.fr
Frédéric Marchand
metadata author
position: Engineer
INRAE U3E, Pôle OFB-INRAE-Agrocampus Ouest-UPPA pour la gestion des migrateurs amphihalins dans leur environnement
65 rue de St Brieuc, CS 84215
Rennes
35042
FR
Telephone: +33223485786
email: frederic.marchand@inrae.fr
Nadine Herrard
programmer
position: Programmer
INRAE U3E, Pôle OFB-INRAE-Agrocampus Ouest-UPPA pour la gestion des migrateurs amphihalins dans leur environnement
65 rue de St Brieuc, CS 84215
Rennes
35042
FR
Telephone: +33223485786
email: Nadine.Herrard@inrae.fr
GBIF France
distributor
position: IT support
GBIF France
MNHN Géologie CP48, 43 rue Buffon
Paris
75005
FR
Telephone: +33140798065
email: connexion@gbif.fr
Didier Azam
administrative point of contact
position: Researcher
INRAE U3E, Pôle OFB-INRAE-Agrocampus Ouest-UPPA pour la gestion des migrateurs amphihalins dans leur environnement
65 rue de St Brieuc, CS 84215
Rennes
35042
FR
Telephone: +33223485786
email: Didier.Azam@inrae.fr
Frédéric Marchand
administrative point of contact
position: Engineer
INRAE U3E, Pôle OFB-INRAE-Agrocampus Ouest-UPPA pour la gestion des migrateurs amphihalins dans leur environnement
65 rue de St Brieuc, CS 84215
Rennes
35042
FR
Telephone: +33223485786
email: frederic.marchand@inrae.fr