Abundances and biological traits of eels sampled in the survey of eels abundance Indices in the Bresle river (France)

Data Records

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 339 records.

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How to cite

Researchers should cite this work as follows:

Josset Q., Flesselle A., Floquet A., Macquet T., Beaulaton and Marchand F. (2024). Abundances and biological traits of eels sampled in the survey of eels abundance Indices in the Bresle river (France)

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Researchers should respect the following rights statement:

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.

GBIF Registration

This resource has been registered with GBIF, and assigned the following GBIF UUID: faa02037-fddd-4c62-9f28-2d0d0fee2468.  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.

Keywords

Population density; catch effort

Contacts

Geographic Coverage

The Bresle river in Normandy (France). http://www.sandre.eaufrance.fr/geo/CoursEau/G01-0400

Temporal Coverage

Project Data

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.

Sampling Methods

On the Bresle, sampling is conducted at 14 sites spread along the mainstem, in the area of the hydrographic network colonized by the European eel.

Method step description:

1. Fish capture was carried out with a portable electrofishing equipment. The same gear was used since the beginning of the data collection, namely a Martin Pêcheur from DREAM Electronique, It is tuned to produce a pulsed DC with a 400 Hz frequency, 250-300 volts and a square-waveform between 4 and 10% duty cycle. Fishing is operated according to the following steps : 1. Two large dip-nets with metal frames are placed facing the current, lying on the bottom, and kept at a fixed position. In the case of a watercourse of reduced width, only one is used. 2. The anode scans an area about 2-2.5 m upstream of the dip-nets in the vein of water filtered by them. The electric current is applied for a duration of 30s, with a circuit cut after 15s and for a duration of 2s. 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. The electric field is variable, adapted to the conductivity of the water. In the areas where there are many roots or stones, the operator may have to fish longer in order to attract the fish out of their hiding place. 4. Individuals are transferred into a bucket previously filled with water. 5. The whole team moves from bank to bank 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 and the team goes the other way. 6. 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 tip of the caudal fin (1 millimeter precision). Fish are then weighed (0.2 g precision). All the fish sampled are then released in their original site of capture.

Additional Metadata