Getting eels to return to live in their potential habitat in the Oria river basin – in the Basque province of Gipuzkoa – is the aim of the repopulation programmes being undertaken by the Basque Water Agency, the Azti-Tecnalia technological centre and the Provincial Government of Gipuzkoa. Experts from these bodies will transfer 2-month old eels caught from a migration passage/breeding ground on the river belonging to this Provincial Government, at the tidal limit of the Oria river (Orbeldi) and upstream at the Asteazu creek. The release spot is a high-quality habitat for the development of the eels and which, due to obstacles to migration, currently does not have populations of this species.
The populations of the European eel (Anguilla anguilla) have undergone intense decline over the past 25 years. With the goal of improving the situation of the species in our rivers, since 2011, Azti-Tecnalia specialists, in collaboration with the Biodiversity Foundation, the Gipuzkoa Provincial Government and the Basque Water Agency (URA in its Basque synonym), have been carrying out a number of pilot experiments in the river Oria. Amongst these are three different repopulation actions.
The first, undertaken in June 2011, involved transporting more than 2,400 two-month old eels and wild eels caught during their upstream migration from the Orbeldi capture station (at the lower reach of the river Oria) to Ursuaran. The second and third focused on the release of 6.4 kilogrammes of eel elvers caught by Oria river fishermen. In this case, half of the elvers were reintroduced directly into the river (at Zegama), and the other half were growth-fed for two months at the Mutriku Aquaculture School, to be subsequently released to the river Agauntza, in Ataun.
Promising results
The three actions yielded promising results: the eel elvers survived and grew notably, especially those from the migration passage and that were subsequently transferred to other zones of the rivers which have a quality habitat for the species but where, due to the presence of obstacles to the colonisation of the species, the eel population had disappeared. This fact spurred URA, with the collaboration of the Gipuzkoa Provincial Government and Azti-Tecnalia, to continue transferring the eels upstream on an annual basis. On this occasion the chosen point for release was the Asteasu stream.
Management plan in the Basque Country for the European eel
In 2007, the European Council of Ministers passed measures for the recovery of the population of the European eel – EC Regulation 1100/2007. This Regulation obliged all member countries to draw up management plans by December 2008. The repopulation and transport of individuals is one of the measures set out in the 1100/2007 Regulation to increase the presence of the species in various European river basins.
The Department of Agriculture and Fisheries of the Basque Government and the three Basque Provincial Governments – as the relevant authorities in the matter – drew up the ‘Management Plan for the European Eel within the Autonomous Community of the Basque Country’, passed by the European Commission in October 2010, as a result of the EC 1100/2007 Regulation of September 2007, setting out measures for the recovery of the population of the European eel, as well as monitoring and research programmes.
The programme involves a monitoring plan and a research plan, aimed at reducing the death rate amongst eels, putting forward measures for limiting fishing, actions for the re-introduction of eels, improving the habitats and connectivity of the rivers, action involving aquiculture and combatting predation.
Elver fishing began to be regulated specifically with the 41/2003 Decree of the Basque Government (modified by the 107/2005 Decree) requiring a personal licence for eel fishing and the classification of the activity as recreational, the sale of the eel elvers caught in our rivers being thus expressly prohibited. The recovery plan involved a series of limitations to the fishing of the elver:
- Strict compliance with the conditions for the renovation of the fishing licence.
- Catch limit: 2 kg of elvers per fisherman per day, in all the modes and all rivers.
- Shortening the fishing season from 15 October – 15 March to 15 November – 31 January.
- Declaring 3 main rivers as permanent reserves: Oiartzun, Urumea and Barbadun and 2 secondary ones: Iñurritza and Andrakas.
Likewise, the recovery plan prohibited fishing for adult eels.
Scientific interest and a great fishing tradition
The European eel – scientific name Anguilla anguilla -, is a peculiar species from a biological perspective, is of great scientific interest and has a great fishing tradition in many areas including the Basque Country. Present throughout almost all of Europe and the North of Africa, the greatest part of its growth cycle takes place in fresh water and it reproduces in the Saragossa Sea.
Eel populations have undergone an intense decline throughout all of Europe in recent decades as a consequence of the accumulation of various factors: loss of and changes in their habitats, contamination, obstacles to their displacement in the rivers, overfishing, oceanographic changes, diseases and parasitism.
Translation: Basque Research
