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Previous research indicated that high predictive performance in species distribution modelling can be obtained by combining both biotic and abiotic habitat variables. However, models developed for fish often only address physical habitat characteristics, thus omitting potentially important biotic factors. Therefore, we assessed the impact of biotic variables on fish habitat preferences in four selected stretches of the upper Cabriel River (E Spain).The occurrence of Squalius pyrenaicus and Luciobarbus guiraonis was related to environmental variables describing interspecific interactions (inferred by relationships among fish abundances) and channel hydro-morphological characteristics. Random Forests (RF) models were trained and then validated using independent datasets. In both training and validation phases, RF showed high performance. Water depth, channel width, fine substrate and water-surface gradient were selected as most important habitat variables for both fish. Results showed clear habitat overlapping between fish species and suggest that interspecific competition is not a strong factor in the study area.

Although numerous pumping stations (PS) have been used by water managers for numerous applications on rivers, canals and other water bodies, their impact on fish populations is poorly understood. This study investigates European eel, Anguilla anguilla (L.), mortality after natural downstream passage through a propeller pump and two Archimedes screw pumps at two PSs on two lowland canals in Belgium. Fyke nets were mounted permanently on the outflow of the pumps during the silver eel migration periods. Based on the condition and injuries, maximum eel mortality rates were assessed. Mortality rates ranged from 97 ± 5% for the propeller pump to 17 ± 7% for the large Archimedes screw pump and 19 ± 11% for the small Archimedes screw pump. Most injuries were caused by striking or grinding. The results demonstrate that PSs may significantly threaten escapement targets set in eel management plans.

Soares Costa, RM.; Martinez-Capel, F.; Muñoz Mas, R.; Alcaraz-Hernández, JD.; Garófano-Gómez, V. (2012). Habitat suitability modelling at mesohabitat scale and effects of dam operation on the endangered Júcar nase, Parachondrostoma arrigonis (River Cabriel, Spain). River Research and Applications. 28(6):740-752. doi:10.1002/rra.1598. 1 This is a pre-copyedited, author-produced PDF version following peer review of this article, which has been 1 published in definitive publisher-authenticated form at: The presence of large dams affects habitat availability, often regarded as the primary factor that

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