A survey started in 2006 is conducted every year in early autumn (late September to early October) to quantify the abundance of eels in the Nivelle in Pays Basque. The data consist of abundance indices and biological traits measured on the fish sampled: length, weight ... 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 995 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:
Lange F, Bardonnet A, Daverat F, Rives J, Huchet E, Guéraud F (2023): Abundances and biological traits of eels sampled in the survey of eels abundance Indices in the Nivelle river (France). v1.2. Institut national de recherche pour l’agriculture, l’alimentation et l’environnement (INRAE). Dataset/Occurrence. https://ipt.gbif.fr/resource?r=inrae_nivelle_iaa&v=1.2
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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: c716f665-325c-4656-a096-fc4fd683d407. 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.
Occurrence; Observation; population density; eel; population distribution; catch effort
- Metadata Provider ●
- Point Of Contact
The Nivelle river in Basque Country (France). http://services.sandre.eaufrance.fr/Courdo/Fiche/client/fiche_courdo.php?CdSandre=S52-0400
|Bounding Coordinates||South West [43.253, -1.669], North East [43.391, -1.467]|
|Start Date / End Date||0034-03-13 / 0018-03-15|
In the Nivelle, sampling is conducted at 10 sites spread along the mainstem and tributaries. The sites are visited once a year at the beginning of autumn (end of September to early October)
|Study Extent||Nivelle river, CdSandre=S52-0400 Latitude between 43.2426 and 43.3912; longitude between -1.4799 and -1.6694 Source latitude and longitude : 43.2173 -1.5231 Last confluence point latitude and longitude : 43.3854 -1.6639 The Nivelle is a 39 km long coastal stream of Pays Basque. It has its source in Spain and flows into the Bay of Biscay at Saint-Jean-de-Luz. Its drainage basin has a surface area of 238 km2, and is dominated by marly-calcareous formations. It is essentially agro-pastoral with more than 50% of the land area made of moors (Dumas, 2003). The oceanic climate, mild and wet (1700 mm year-1 in St-Pe´e-sur-Nivelle), provides a mean annual discharge of 5.4m3 s-1 downstream from the confluence of the main tributary, the Lurgorrieta, and 7 m3 s-1 at the mouth. The water, neutral to slightly alkaline, is of good quality upstream from Saint-Pée-sur-Nivelle, but deteriorates downstream.|
Method step description:
- 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 of about 2-2.5 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. 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. Eels 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. Overall the fishing method is modeled on the principle of De Lury fishing (Fisheries by stock depletion). Each year, an identical sector with an area close to 100 m2 is inventoried using this method. Juvenile abundance is quantified by the number of individuals captured for a unit effort (Two or three fishing under the conditions specified above, depending on the quantity of individuals captured).
- 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). All the fish sampled are then released in their original site.