Fishes in MZNA-VERT: populations affected by the Itoiz dam in the Irati river (Spain).

Study Extent

The specimens were captured in three localities of the river Irati: Aós, Rípodas and Liédena, 5.4, 20.8 and 36 km downstream from the dam in six consecutive years, from 2005 to 2011.

Sampling

Data was collected as part of a study about the impact of the construction of the dam of Itoiz in the Irati river. Fish sampling was performed using a back-pack electrofishing unit (Hans Grassl model IG200/2D, 300-600V, 0.2-2A). Fish sampling were carried out in the end of June from 2005 to 2011, just before the beginning of summer water release of the dam. The captured individuals were sedated with 2-phenoxyethanol, identified, counted and measured (total length in mm). Then, fish were returned to the river (MZNA, Pamplona, Spain). Species identification was performed by R. Miranda, using suitable literature.

Quality Control

Species identification was performed by R. Miranda using suitable literature (Maitland & Linsell 1977) and scientific names were validated using the W. N. Eschmeyer’s Catalog of Fishes (Eschmeyer 2014). Specimens were returned to the river or deposited in the Museum of Zoology of the University of Navarra. Each specimen was labelled with a unique collection number. Darwin test software (v3.3 Ortega-Maqueda and Pando 2008) was used to check out possible mistakes in the coordinates, characters and the format of dates.

Method steps

1. Specimens were sampled following the procedure described in the Sampling description section. The individuals were identified, measured and released in the majority of cases. Some specimens were euthanized and deposited on the Museum of Zoology of the University of Navarra in labelled jars first with formalin and, more recently, with 70% ethyl alcohol. Field data was revised, digitalised and incorporated to the MZNA database (Zootron v4.5, Ariño 1991). The dataset was exported to DarwinCore v1.4 format and revised to correct errors to adequate it to DarwinCore standars. Metadata information was added and the Darwin Core Archive was incorporated to the Spanish GBIF IPT.

All specimens were identified to the species level when possible, using the Guide to Freshwater Fish of Britain and Europe (Maitland P. S. & Linsell K., 1977). Nine species were recorded, of which five belonged to the Cyprinidae family. The rest of the collected species belong to the families Anguillidae, Cobitidae, Nemacheilidae and Salmonidae. In number of individuals, the most abundant family is Cyprinidae as well, with the 65% of the captures. This is followed by the family Nemacheilidae (25%) and Salmonidae (9%). Moreover, 5 of the species recorded in this dataset are endemic from the Iberian Peninsula and 1 is an introduced species. One of the native species recorded, Anguilla anguilla, is Critically Endangered. Among the endemic species Cobitis calderoni is Endangered, according to the IUCN Red List.

1. Anguilla anguilla
   common name: Eel rank: species
2. Barbatula quignardi
   common name: Pyrenean stone loach rank: species
3. Cobitis calderoni
   common name: Northern Iberian spined- loach rank: species
4. Alburnus alburnus
   common name: Bleak rank: species
5. Gobio lozanoi
   common name: Pyrenean gudgeon rank: species
6. Luciobarbus graellsii
   common name: Ebro barbel rank: species
7. Parachondrostoma miegii
   common name: Ebro nase rank: species
8. Phoxinus bigerri
   common name: Pyrenean minnow rank: species
9. Salmo trutta
   common name: Brown trout rank: species

The specimens recorded in this dataset are collected in the Irati river, a tributary of the river Ebro (Spain), downstream of the Itoiz dam.