Project details

During the spring of 2025, an agreement was signed with the Consorci de l'Alta Garrotxa to carry out conservation actions on two ponds located in the municipality of Oix (Alta Garrotxa): Bassa de Camporiol and Bassa de Palomeres. The interventions aim to make extensive livestock farming compatible with biodiversity preservation, as well as to reduce the impact of invasive species on aquatic ecosystems.

The main action at the Camporiol pond, in collaboration with the Consorci de l’Alta Garrotxa and the owners of the Camporiol estate (municipality of Montagut i Oix), consisted of restoring a semi-permanent pond that had exotic fish causing a severe ecological impact. The intervention involved draining the pond and removing the exotic fish.

The capture action was carried out using electrofishing, a technique that uses a controlled electrical current to temporarily stun fish, facilitating their collection with dip nets. To optimize results, the pond was previously drained using a motor pump. This allowed the team to access every corner of the pond while reducing hiding spots for the fish, thereby increasing the intervention's success rate. This technique was performed by specialized personnel from the Center for the Study of Mediterranean Rivers (CERM).

As a result of the action, two koi carp (Cyprinus carpio) and approximately one thousand goldfish (Carassius auratus) were removed—both non-native and invasive species. Their presence poses a risk to natural aquatic ecosystems, as they cause habitat alterations, compete with native fauna, degrade water quality, and particularly prey on invertebrate and amphibian larvae, among other negative impacts on biodiversity.

Before and after the intervention, the Bionexus Foundation conducted detailed monitoring of the pond (studying aquatic macroinvertebrates, zooplankton, and physicochemical water variables) to evaluate both the effects of exotic fish and the efficiency of the restoration action.D