Fishes in MZNA-VERT: baseline freshwater sampling campaigns

Study Extent

The specimens were captured in 61 localities of different tributary basins of the Ebro and Duero rivers (Spain) between 1995 and 2014. The rivers drain into the Atlantic Ocean and the Mediterranean Sea. The climate is Mediterranean with hot and dry summers and humid winters. This varies with the altitude and oceanic influence.

Sampling

Data was collected as part of different studies such government-funded assessments and management projects. Sixty one localities of Spain were sampled, the majority in Navarra (46% of the captures). In total, there were 16464 specimens observed. The Ebro basin was the most sampled. The main sampling method was electric fishing, using a back-pack electrofishing unit. Two electrofishing methods were used: three-run depletion between two stop-nets and semi-quantitative surveys, giving fish densities by catch per unit of effort (CPUE, number of specimens captured per hour, Lobón-Cerviá 1991). The period of time of the semi-quantitative samplings varied between 15 minutes to 2 hours. The captured individuals were sedated with 2-phenoxyethanol, identified, counted and measured (total length in mm). However, there are not measured specimens in some samplings due to the type of project. Then, fish were returned to the river or euthanized and deposited on the Zoological Museum of the University of Navarra (MZNA, Pamplona, Spain). Species identification was performed by R. Miranda.

Quality Control

Species identification was performed by R. Mirandausing 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 Zoological Museum 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 individuales were identified, measured and released in the majority of cases. In some cases the specimens were not measured or euthanized and deposited on the Zoological Museum 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). Twenty-three species were recorded in all Spain, of which 12 belong to the Cyprinidae family. The rest of the collected species belong to the families Cobitidae, Nemacheilidae, Salmonidae, Percidae, Esocidae, Bleniidae, Centrarchidae, Siluridae, Poeciliidae and Ictaluridae. In number of individuals, the most abundant family is Cyprinidae as well, with the 86% of the captures. This family is followed by Salmonids (5.5%). The most captured species was Phoxinus bigerri. Moreover, 7 of the species recorded in this dataset are endemic from the Iberian Peninsula and 12 are introduced species. One of the endemic species recorded, Cobitis calderoni is Endangered according to the IUCN red list.

1. Salaria fluviatilis
   common name: River blenny rank: species
2. Lepomis gibbosus
   common name: Pumpkinseed rank: species
3. Micropterus salmoides
   common name: Largemouth black-bass rank: species
4. Barbatula quignardi
   common name: Pyrenean stone loach rank: species
5. Cobitis calderoni
   common name: Northern Iberian spined- loach rank: species
6. Achondrostoma arcasii
   common name: Bermejuela rank: species
7. Alburnus alburnus
   common name: Bleak rank: species
8. Barbus haasi
   common name: Iberian redfin barbel rank: species
9. Carassius auratus
   common name: Goldfish rank: species
10. Cyprinus carpio
    common name: Carp rank: species
11. Gobio lozanoi
    common name: Pyrenean gudgeon rank: species
12. Luciobarbus graellsii
    common name: Ebro barbel rank: species
13. Parachondrostoma miegii
    common name: Ebro nase rank: species
14. Phoxinus bigerri
    common name: Pyrenean minnow rank: species
15. Rutilus rutilus
    common name: Roach rank: species
16. Scardinius erythrophthalmus
    common name: Rudd rank: species
17. Squalius laietanus
    common name: Ebro chub rank: species
18. Esox lucius
    common name: Pike rank: species
19. Ameiurus melas
    common name: Catfish rank: species
20. Sander lucioperca
    common name: Pikeperch rank: species
21. Salmo trutta
    common name: Brown trout rank: species
22. Silurus glanis
    common name: Wels catfish rank: species
23. Gambusia holbrooki
    common name: Eastern mosquitofish rank: species

All specimens were collected in Spain. Almost half of the individuals were from Aragón (48%) and the rest were scattered through Navarra (36%), La Rioja (13%) and Castilla y León (4.6%). The rivers sampled are tributaries of the Ebro and Duero, on the north of Spain, in the Iberian Peninsula, southern Europe. Their basins flow into Atlantic and Mediterranean seas.