Effects of high water discharge from Alcalá dam on fish larval stages of Guadalquivir estuary

Abstract

Event Abstract Back to Event Effects of high water discharge from Alcalá dam on fish larval stages of Guadalquivir estuary Juan Miguel Miró1*, César Megina1, Iñigo Donázar-Aramendía1, Emilio Sánchez-Moyano1, Isabel García-Asencio1 and J. Carlos García-Gómez1 1 Facultad de Biología, Universidad de Sevilla, Departamento de Zoología, Spain Estuaries are unstable systems, generally with a limited number of species. However, they support a high productivity, frequently being important nursery zones where postlarvae and juvenile fishes find some good conditions for its development. Most of estuaries have the freshwater input regulated by dams, altering estuarine natural hydrological regime. Nevertheless, high discharges can modify sharply column water structure, influencing organisms that live inside by eliminating salinity gradient or increasing turbidity and flow velocity. These changes affect nursery function of estuaries. In this study, we analyse the effects of freshwater input episode, which come from Alcalá Dam after a high rainfall, on larval stages of Guadalquivir estuary (Southwestern Spain). Sampling were carried out before (24 m3/s), during (151 m3/s) and after (14 m3/s) a high dam discharge. Samples were taken with a zooplankton net with 1 meter mouth diameter and 1000 µm mesh size. Double oblique tows were performed from surface to bottom during flood tide, in the main channel. Samples were taken along the estuarine section where larval stages had been detected, including some external marine areas (~35‰). In every sampling area 3-5 replicated tows were done. Physiochemical data of the water column were also recorded in all water masses with a multi-parameter probe (salinity, temperature, turbidity, HDO, depth and pH). First preliminary results were analysed. Data from probe showed relevant changes in water column parameters and, even if this is a well-mixed estuary, we observed a salinity stratification up until 15 grades from the bottom to the surface during high discharge episode. Abundance of fish juvenile phases decreased markedly during high fresh water inputs episode, although it recovered partially after a short period. Still, this effect was not equal for all species. Additional episodes of high dam discharge will be sampled and analysed to obtain a more general pattern and to propose management strategies related to river discharges. Acknowledgements We thank to Autoridad Portuaria de Sevilla (APS) for financial support. This work was partially supported by the V Plan Propio Universidad de Sevilla via a pre-doctoral grant. Keywords: Fish larval stages, Dam discharge, Water column structure, Nursery area, Guadalquivir estuary Conference: XIX Iberian Symposium on Marine Biology Studies, Porto, Portugal, 5 Sep - 9 Sep, 2016. Presentation Type: Poster Presentation Topic: 1. ECOLOGY, BIODIVERSITY AND VULNERABLE ECOSYSTEMS Citation: Miró J, Megina C, Donázar-Aramendía I, Sánchez-Moyano E, García-Asencio I and García-Gómez J (2016). Effects of high water discharge from Alcalá dam on fish larval stages of Guadalquivir estuary. Front. Mar. Sci. Conference Abstract: XIX Iberian Symposium on Marine Biology Studies. doi: 10.3389/conf.FMARS.2016.05.00118 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 29 Apr 2016; Published Online: 03 Sep 2016. * Correspondence: PhD. Juan Miguel Miró, Facultad de Biología, Universidad de Sevilla, Departamento de Zoología, Sevilla, Sevilla, 41012, Spain, jmmiro@us.es Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Juan Miguel Miró César Megina Iñigo Donázar-Aramendía Emilio Sánchez-Moyano Isabel García-Asencio J. Carlos García-Gómez Google Juan Miguel Miró César Megina Iñigo Donázar-Aramendía Emilio Sánchez-Moyano Isabel García-Asencio J. Carlos García-Gómez Google Scholar Juan Miguel Miró César Megina Iñigo Donázar-Aramendía Emilio Sánchez-Moyano Isabel García-Asencio J. Carlos García-Gómez PubMed Juan Miguel Miró César Megina Iñigo Donázar-Aramendía Emilio Sánchez-Moyano Isabel García-Asencio J. Carlos García-Gómez Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.