ABUNDANCE VARIABILITY OF GELATINOUS PLANKTON ON THE MEDITERRANEAN SPANISH COASTS: A COMBINED ANALYSIS AT REGIONAL AND LOCAL SCALES Laura Prieto *, Ana Genua , Nuria Sanz and Gabriel Navarro Instituto de Ciencias Marinas de Andalucia (ICMAN) CSIC - laura.prieto@icman.csic.es CUDOMAR SL,c/ Drassanes s/n, El Campello, 03560, Alicante, Spain Abstract The massive outburst of jelly organisms on the Spanish coast is a phenomenon with relevant implications at the socio -economic level. The aim of this study is to combine the abundance variability of these organisms with the physical and oceanographic forcing. The interannual variations of gelatinous plankton by different sources of data at regional scale (Alboran and Balearic Sea) are analyzed since 2007. Also, at local scale daily observations of abundance of jellyfish were estimated since 2011 in a fixed station offshore the Alicante coast. Remote sensing data are analyzed to characterize which are the time windows of increased proliferation of gelatinous plankton and their connection with the physical environment. Keywords: Alboran Sea, North - Western Mediterranean, South - Western Mediterranean, Medusae 1 1 2 1 1 2 The worldwide concern about the massive proliferation of marine gelatinous zooplankton in the last decades has resulted in extensive recent work [1]. However, there is still no agreement about the underlying cause for their occurrence. Several hypotheses have been tested, thus the processes involved are not always mutually exclusive. Eutrophication, over-fishing, species introduction and climate change, are some of the proposed explanations [2]. Given the magnitude of ecological and socio-economic consequences of jellyfish outbreaks in the Mediterranean Sea, the understanding of mechanisms driving them is of great importance for the prediction of future scenarios. The identification and location of the target species as well as the gathering of relevant data seems a first valuable step through population dynamics and ecological modelling. The aim of this study is to combine the abundance variability of these organisms with the physical and oceanographic forcing. The interannual variations of gelatinous plankton by different sources of data at regional scale (Alboran and Balearic Sea) are analyzed since 2007 (fig. 1). Fig. 1. Mean remote sensing sea surface temperature and surface chlorophyll and jellyfish sightings during March 2011 in the Balearic Sea. Also, at local scale daily observations of abundance of jellyfish were estimated since 2011 in a fixed station (38º 25.200' N, 00º 20.850' W) sited near by a marine culture of fish floating cages, 1.87 miles offshore the Alicante coast (fig. 2). The number of species identified in this station was a four: Chrysaora hyoscella, Cotylorhiza tuberculata, Pelagia noctiluca and Physalia physalis. The specie most frequent and also most abundant was, in both years sampled, Pelagia noctiluca. Fig. 2. Daily abundance variability of Pelagia noctiluca 1.87 miles offshore the Alicante coast, Spain, during 2001 and 2012. The exact location is observed in the map of fig.1 with a dot. Remote sensing data are analyzed to characterize which are the time windows of increased proliferation of gelatinous plankton and their connection with the physical environment. References 1 - Condon R.H., Graham W.M., Carlos M. et al., 2012. Questioning the Rise of Gelatinous Zooplankton in the World's Oceans. BioScience, 62 (2): 160-169. 2 - Richardson A.J., Bakun A., Hays G.C. and Gibbons M.J., 2009. The jellyfish joyride: causes, consequences and management to a more gelatinous future. Trends in Ecology and Evolution, 24 (6): 312-322. 547 Rapp. Comm. int. Mer Médit., 40, 2013 Powered by TCPDF (www.tcpdf.org)