Conservation of endangered species

The continuous regression of the margaritona mollusk in the Ebro basin endangers the conservation of the fritillary, the only fish native to this basin that feeds on its larvae.

The margaritona(Margaritifera auricularia) is a priority conservation mollusk in Spain. It is listed in the "critically endangered" category both in Spain and internationally. Unfortunately, despite the efforts made during the last decades, its status has continued to worsen. In fact, this process has accelerated in recent years due to a drastic increase in mortality in its main Iberian population, located in the Canal Imperial de Aragón. Thus, it is urgent to plan diverse, well-considered and strategically selected measures to avoid its extinction final in Spain. On the other hand, the fritillary(Salaria fluviatilis), the only native fish still present in the basin that is a recognized host of its larvae, is also an endangered species that is still immersed in a progressive regression, although it still maintains some population nuclei of density B; its conservation and recovery are inevitably linked to the margaritona.

The general goal of project is the long-term conservation deadline of the margaritona(Margatifera auricularia) through the identification of suitable river sections to establish new nuclei of specimens in the Ebro basin, and the improvement of available stocks of its host fish, the fritillary (Salaria fluviatilis).

Specific objectives of this project include the following:

• Locate river sections with hydromorphological and biotic characteristics suitable for the reception of M. auricularia specimens, whether translocated adults or juveniles obtained in captivity.

• To evaluate and update the conservation status of the populations of fritillary(S. fluviatilis) in the middle stretch of the Ebro, the only native host fish of this naiad that survives in the basin.

• Create a network of ponds or other bodies of water in custody with the capacity to host new stable nuclei of fritillary.

• Establish new fritillary populations in the agreed bodies of water that constitute a reservation in the face of their decline and a source of specimens for assisted reproduction of M. auricularia.

• To test low-cost punctual measures to favor the reproduction of M. auricularia in its few currently known river nuclei).

• Improve the involvement and awareness of society in the conservation of the most endangered aquatic fauna, and specifically of the margaritona and the fritillary, at challenge .

• Transfer specific scientific-technical information and results.

SOS Margaritona is a project funded by the Biodiversity Foundation and the Ministry for the ecological transition, led by the Associació La Sorrellona.