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.
The data in this occurrence resource has been published as a Darwin Core Archive (DwC-A), which is a standardized format for sharing biodiversity data as a set of one or more data tables. The core data table contains 43,782 records.
1 extension data tables also exist. An extension record supplies extra information about a core record. The number of records in each extension data table is illustrated below.
This IPT archives the data and thus serves as the data repository. The data and resource metadata are available for download in the downloads section. The versions table lists other versions of the resource that have been made publicly available and allows tracking changes made to the resource over time.
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How to cite
Researchers should cite this work as follows:
Jeannot N, Azam D, Guilloux Y, Prévost E (2023): Abundances and biological traits of the juveniles salmon sampled in the survey of Salmon abundance Indices in the Scorff river (France). v1.17. Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE). Dataset/Occurrence. https://ipt.gbif.fr/resource?r=inra_rennes_scorff&v=1.17
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The publisher and rights holder of this work is Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE). This work is licensed under a Creative Commons Attribution (CC-BY) 4.0 License.
This resource has been registered with GBIF, and assigned the following GBIF UUID: 89064e3a-aa3c-495d-b236-092e1dae7042. Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE) publishes this resource, and is itself registered in GBIF as a data publisher endorsed by GBIF France.
Samplingevent; Population density; population distribution; catch effort; salmo salar; salmon; Occurrence
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The Scorff, a coastal river in Brittany (France)
|Bounding Coordinates||South West [47.77, -3.34], North East [48.17, -3.25]|
No Description available
|Start Date / End Date||1993-09-27 / 2022-09-29|
The Research Observatory on Diadromous Fish in Coastal Streams (ORE DiaPFC) is a research infrastructure steered by INRAE in partnership with OFB and part of the OFB-INRAE R&D center. It’s focused on the study of the evolution of diadromous fish populations under the influence human induced environmental changes that affect these rivers (mainly climate and effects of agriculture). Diadromous species of primary interest are salmon (Salmo salar), trout (Salmo trutta), eel (Anguilla Anguilla), shads (Alosa sp.), and lampreys (Lampetra sp. and Petromyzon marinus). These species are threatened by the consequences of human activities. They are flagship species for the biodiversity of coastal streams. Nowadays, these streams are the main refuges for diadromous fish that have disappeared or dramatically declined on larger rivers. This ERO DiaPFC is a Research Infrastructure based on four coastal streams of the Atlantic and Channel coast of France: the Bresle and the Oir in Normandy, the Scorff in Brittany and the Nivelle in the Pays Basque. These four rivers are equipped with diadromous fish trapping facilities and are thoroughly and continuously surveyed from the mid 1980s. They are twinned with experimental ecology facilities located in Rennes (Brittany) and Saint-Pée-sur-Nivelle (Pays Basque). This set of facilities is complemented by individual-based eco-genetic simulators for in silico experimentation on virtual populations.
|Title||ORE-DiaPFC Observatoire de Recherche en Environnement des poissons diadromes sur les Petits Fleuves Côtiers - ERO DiaPFC Ecological Research Observatory on Diadromous Fish in coastal streams|
|Funding||- INRAE : French National Institute for Agricultural, Food en Environment Research - OFB : French Office for Biodiversity - FEAMP : (European Fund for Maritime Affairs and Fisheries). - Since 2017, data collected on salmon in the framework of the ORE DiaPFC have been included in the national program for the data collect in support of scientific advice for the Common Fisheries Policy for the European regulations on fisheries management. In this context, INRAE and OFB contribute to the National Work Program piloted by the DPMA of the Ministry of the Environment. This program is financially supported by FEAMP and FEAMPA.|
|Study Area Description||ERO DiaPFC is a Research Infrastructure based on three coastal streams of the Atlantic and Channel coast of France: the Bresle and the Oir in Normandy, the Scorff in Brittany and the Nivelle in the Pays Basque|
|Design Description||The issue of 'Research Observatory on Diadromes Fish in Coastal Rivers (ORE DiaPFC) is to study the evolution of diadromous fish populations as a result of environmental changes (climate change and changes related to agriculture ) that affect these rivers.|
The personnel involved in the project:
- Principal Investigator
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).
|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.|
Method step description:
- 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).
|Collection Name||Colisa - Collection of Ichtyological Samples|
|Specimen preservation methods||Dried, Other, No treatment|
|Curatorial Units||Between 21,925 and 21,925 Fins , Between 945 and 945 Scales|
- 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.
This data set is intended to be updated annually.