Water diversion reduces abundance and survival of two Mediterranean cyprinids

作者：Merciai Roberto; Bailey Larissa L; Bestgen Kevin R; Fausch Kurt D; Zamora Lluis; Sabater Sergi; Garcia Berthou Emili^*

来源：Ecology of Freshwater Fish, 2018, 27(1): 481-491.

DOI：10.1111/eff.12363

• Barbus meridionalis
• Cyprinidae
• hydrologic alteration
• mark-recapture study
• population density
• Squalius laietanus

Water flow is a fundamental characteristic required for the ecological integrity of stream ecosystems. However, populations of many freshwater fishes in the Mediterranean region are threatened by man-induced drought due to water diversion. Mark-recapture methodology is an effective tool for estimating fish abundance and survival probability, but it has been seldom used with Mediterranean freshwater fish. We tagged over 2,400 individuals of two threatened cyprinids (Mediterranean barbel Barbus meridionalis and Catalan chub Squalius laietanus) inhabiting an Iberian stream affected by water diversion, and used mark-recapture methods to evaluate the effects of flow, temperature and depth on their apparent survival and abundance at hydrologically altered and perennial reaches. Based on estimates over the summer drying season, survival of Mediterranean barbel was more than six times higher in an upstream reach with permanent flow than a middle reach impacted by water diversion. Water depth was the most important habitat feature accounting for differences in survival, with both barbel and chub exhibiting higher survival and abundance at permanent sites farther downstream where flow had been restored and in an unaltered tributary. Our results show clear negative impacts of water diversion on fish populations. Both species, but particularly barbel, have life-cycle characteristics that may allow populations to recover quickly if natural streamflow was restored by conserving water and reducing water diversion.

• 出版日期2018-1