EDP Foz-Tua: Fishes – Ecological Monitoring Program [2011-2017]

Study Extent

The data were collected along the Tua lower valley (Northeast Portugal), up to 52 km from the mouth, and in its main tributaries, in the municipalities of Alijó, Carrazeda de Ansiães, Murça, Vila Flor and Mirandela.

Sampling

The capture method employed was electric fishing and the samples were taken during the day, by a team of three to four elements, using a portable device with a gasoline generator set (for safety reasons used as a fixed element), with pulsed direct current output (Hans Grassl ELT 60II-HI, 500-1000 V, 1300W), or a portable rechargeable battery pack for dorsal transport with continuous pulse output (Hans Grassl IG200 / 2C; 400-1000 V; <70 Hz), The methodology adopted depended also on the depth of the section to be sampled: i) In fully wadeable sections (depth <1 m), the operator positioned himself at the downstream limit of the section manipulating the anode, moved in a zigzag movement upstream, ensuring coverage of all habitats in the river system (INAG, 2008); and ii) n sections that are not entirely wadeable (depth >1 m), the operator positioned on the downstream limit of the section, manipulating the anode and moving along the two margins (minimum length of 200 m on each bank was used, according to Oliveira et al., 2007), with the aid of a pneumatic boat, in order to ensure the total coverage of the riparian habitats. During sampling, the welfare of the captured specimens was ensured by depositing them in plastic buckets with portable oxygenators, which were kept in shelters at cover of direct sun exposure. The usual safety measures for working with electrofishing were strictly followed. The captured individuals were identified up to the species, and measured (total length in mm) with the aid of an ichthyometer. After these procedures, the native specimens were returned to their habitat in the vicinity of the capture sites with suitable conditions; at the request of the Institute of Conservation of Nature and Forestry (ICNF), exotic individuals were eliminated.

Quality Control

All individual identifications were performed by qualified technicians

Method steps

1. To be completed

The taxonomic coverage of this dataset spans 1 phylum, 1 class, 3 orders, 5 families, 11 genera and 12 species.

1. Chordata
   rank: phylum
2. Actinopterygii
   rank: class
3. Cypriniformes
   rank: order
4. Cyprinodontiformes
   rank: order
5. Perciformes
   rank: order
6. Cyprinidae
   rank: family
7. Poeciliidae
   rank: family
8. Centrarchidae
   rank: family
9. Percidae
   rank: family
10. Cobitidae
    rank: family

The data were collected along the River Tua (Northeast Portugal) and its main tributaries, up to 52 kms from the mouth, in the municipalities of Alijó, Carrazeda de Ansiães, Murça, Vila Flor and Mirandela.