A project to find out about the current situation of the otter in Spain and other species in the aquatic environment with which it is related.

This project of the Spanish Society for the Conservation and Study of Mammals (SECEM) sought to know the current situation of the otter in Spain and other species associated with aquatic environments that are ecologically related to it.

Although the main objective of the project was to carry out the IV National Otter Survey, other species have also been sampled,such as the European mink Mustela lutreola (endangered), the American mink Neovison vison (exotic Invasive), the water rat Arvicola sapidus (vulnerable), the Iberian desman Galemys pyrenaicus (vulnerable) and the three species of crayfish: Autropotamobius pallipes (endangered), Procambarus clarkii (exotic Invader) and Pacifastacus leniusculus (Exotic Invader). Species, all of them that share habitat with the otter.

6,652 soundings have been carried out and 3,457 UTM 10×10 km grids have been sampled. A georeferenced database of the results has also been created, and a thematic cartography of the target species, and of the other species mentioned, has been generated, analyzing the evolution of the Spanish otter population in the last four decades (1980s, 1990s, 2000s, and 2010s).