Abundances and biological traits of the juveniles trout sampled in the survey of trout abundance Indice on the Scorff river and its tributaries (France)

Description

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Les données de cette ressource occurrence ont été publiées sous forme d'une Archive Darwin Core (Darwin Core Archive ou DwC-A), le format standard pour partager des données de biodiversité en tant qu'ensemble d'un ou plusieurs tableurs de données. Le tableur de données du cœur de standard (core) contient 7 771 enregistrements.

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Comment citer

Les chercheurs doivent citer cette ressource comme suit:

Jeannot N, Azam D, Guilloux Y, Quendo F, Prévost E (2022): Abundances and biological traits of the juveniles trout sampled in the survey of trout abundance Indices (VIGITRUITE®) in the Scorff river (France). v1.16. Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE). Dataset/Occurrence. http://ipt.gbif.fr/resource?r=inra_rennes_scorff&v=1.16

Droits

Les chercheurs doivent respecter la déclaration de droits suivante:

L’éditeur et détenteur des droits de cette ressource est Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE). Ce travail est sous licence Creative Commons Attribution (CC-BY) 4.0.

Enregistrement GBIF

Cette ressource a été enregistrée sur le portail GBIF, et possède l'UUID GBIF suivante : 4a3722ec-9113-41e4-8648-c399d142ae68.  Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE) publie cette ressource, et est enregistré dans le GBIF comme éditeur de données avec l'approbation du GBIF France.

Mots-clé

Samplingevent; Population density; population distribution; catch effort; salmo trutta; trout; Occurrence

Contacts

Couverture géographique

The Scorff, a coastal river in Brittany (France)

Couverture taxonomique

Pas de description disponible

Couverture temporelle

Données sur le projet

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-L'Institut Agro-UPPA 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.

Les personnes impliquées dans le projet:

Méthodes d'échantillonnage

In the Scorff, sampling is carried out at 24 sites distributed along the main branch of the Scorff and mainly on the tributaries of the river system. Sites are visited once a year in early autumn (late August to early September).

Description des étapes de la méthode:

1. At the selected station, the VIGITRUITE® protocol was designed to ensure that sampling is representative of the range of available habitat conditions, without any a priori bias towards the habitat preferences of the species. This condition is central to meet the objective of standardization, to allow comparison of results from different operators and different watercourses, and to authorize the use of density conversion abacuses per 100 m2. 1. After resetting the counter of the fishing tackle and the hand meter, the operator progresses from downstream to upstream in the watercourse. He is followed by the main operator equipped with the 2 landing nets, who must respect the travel instructions given to him by the operator, as well as by the second operator. 2. The operator follows a predefined zigzag path that takes him from one bank to the other along successive diagonals, at an angle of about 45° to the banks. Along its path, it makes electrode lines about 2 meters long, parallel to the current, and from upstream to downstream. After making the first line along the bank, the operator must visualise the next line before moving: it will be placed on the diagonal, its downstream limit always upstream of the previous line. At the end of the diagonal, if the space is too short for a line along the bank, the line will be placed on the next diagonal, always upstream of the previous line to avoid overlapping. 3. Once the location of the haul has been visualised, the operator indicates to the main fisher where to immerse his semi-circular net, i.e. upstream of the previous haul and offset on the diagonal. The fisher makes sure that the net is well placed on the bottom. If there is any difficulty in placing the net, the operator may decide to shift the position of the haul significantly. The haul is made, then the position of the next haul is displayed, and so on. The result is a sampling by regularly spaced tows from one bank to the other, covering a line of comparable watercourses regardless of the water width of the river. The two stakes marking the downstream and upstream boundaries of the fishing station are also set. 4. For each haul, the operator immerses the electrode about 2 metres upstream of the flat-bottomed landing net. The contact is made when the anode penetrates the water. The fisherman catches the visible fish with his small net, but does not move the large one. The second operator is ready to intervene in case of high abundance. During this operation, it is important that the fishermen catch only the juveniles of the year (0+) and of one year (1+). The presence of larger and older individuals (sub-adults or adults) must not cause a decrease in the team's concentration of juveniles. The hand-held competitor is incremented by one unit at the end of each haul. 5. At the end of the haul, the operator shall leave the anode at the entrance of the large landing net for 1 to 2 seconds before switching off the ignition and instructing the angler to simultaneously raise the flat-bottomed net. The haul made is counted by the hand-counter operated by the bucket holder. Once the collected fish are put in the bucket, the angler follows the operator's instructions to put the large net back in place for the next haul. 6. As the five minutes of fishing approaches, the time counter should be checked before each new haul. Station sampling shall be completed when the effective fishing time (cumulative time of electrical pulses in the water) reaches at least 5 minutes on the counter; no new electrode tows shall be started if the counter already displays 5 minutes. 7. Using the decameter, the width at the downstream stake is measured and its value noted. Then a new width measurement is made by progressing 10 meters upstream, and so on until the end of the station is approached. If necessary, the remaining distance to the upstream post (less than 10 m) is measured to complete the length measurement of the station. 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.
2. Age is verified from scale reading according to standard methods described by Baglinière & al (2022). Bagliniere, J.-L., Hamelet, V., Guéraud, F., Aymes, J.-C., Goulon, C., Richard, A., Josset, Q., Marchand, F., 2020. Guide to the interpretation of the scales and the estimation of the age of brown trout (Salmo trutta) from the French populations. https://professionnels.ofb.fr/en/node/836

Données de collection

Citations bibliographiques

1. 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.
2. 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.

Métadonnées additionnelles