Habitat use of an endangered endemic freshwater fish from Southern Iberia: The Malaga chub Squalius malacitanus in Genal River (Guadiaro basin)

Francisco Blanco-Garrido, Tony Herrera-Grao, Oscar Gavira-Romero

FiSHMED 2018.004: 16p

Abstract : The Malaga chub Squalius malacitanus is an endangered endemic freshwater fish inhabiting a few small basins around the Strait of Gibraltar, Southern Iberia. This work describes the habitat use displayed by the species in Genal River (Guadiaro basin), as well as its population structure along the river and seasons. The fish community was exclusively formed by native species, although this characteristic could change due to the spreading of invasive species previously established in the basin and/or the arrival of new invaders. Our results suggest that the Malaga chub is a habitat generalist, since it occupied the different types of the habitats within the Genal River in proportion to their availability. However, chub abundance tended to decrease in reaches with higher current velocities. Also, the species’ abundance increased in deeper zones, usually with fine substrate, and in the middle reaches of the stream, where the habitat stability was maximum. The abundance decreased in the lower reaches, following the reduction of habitat stability. This pattern was consistent with the size structure displayed along the river and seasons. The scarcity or even the absence of many size classes out of the zones with higher habitat stability was frequent, while these reaches were characterized by a better representation of all size classes. The Genal River seems to be an ideal stream to study the ecology of this unique fish community composed exclusively by native species, a rare fact in the Iberian Mediterranean basins.

Keywords : Squalius malacitanus, habitat use, habitat stability, size structure

Citation : Blanco-Garrido F, Herrera-Grao T, Gavira-Romero O (2018) Habitat use of an endangered endemic freshwater fish from Southern Iberia: The Malaga chub Squalius malacitanus in Genal River (Guadiaro basin). Fishes in Mediterranean Environments 2018.004: 16p. https://doi.org/10.29094/FiSHMED.2018.004

Article first published online : 26 January 2019

FiSHMED is an international scientific journal edited by 
the Iberian Society of Ichthyology – SIBIC