Jarabugo (Anaecypris hispanica) and freshwater blenny (Salaria fluviatilis): habitat preferences and relationship with exotic fish species in the middle Guadiana basin

In this work the habitat preferences of two endangered freshwater sh species, jarabugo (Anaecypris hispanica) and freshwater blenny (Salaria uviatilis) are analysed, and the distribution of both species in relation to the presence of exotic sh species in the middle stretch of the Guadiana basin is assessed (28 sampling sites). The jarabugo as well as the blenny showed a very restricted distribution, mainly jarabugo (only present in 14.3 % of the sites) which in comparison with previous studies suffered a strong reduction on its distribution area (86 %). This species preferred small streams (generally less than 10 m channel width) and with submerged aquatic vegetation, while the blenny appeared mostly in large downstream stretches (> 10 m channel width), a higher water ow, and water availability (permanent water ow) . Based on a randomisation test (Monte Carlo simulation), blenny distribution was random with respect to exotic species. However, the jarabugo and the centrarchidae (Lepomis gibbosus and Micropterus salmoides) never coexisted in the same locations, despite a high probability of co-occurrence expected by chance (Monte Carlo simulation P = 0.965). The spatial segregation between the jarabugo and centrarchids, together with the decline of the former in areas which experienced an increase in centrarchid abundance, suggest these exotics are a threat for the conservation of jarabugo.