engleski

Are the outbreaks of Pelagia noctiluca (Forskäl, 1775) more frequent in the Mediterranean basin?

The holoplanktonic scyphomedusa Pelagia noctiluca (Forskäl, 1771) is known to reach cyclic outbreaks in the western Mediterranean Sea. Major outbreaks have been noticed during the years 1957-1959, 1969-1970, 1982-1984 and 1993-1995. The analysis of recent decades however suggest that the intensity, timing and distribution of Pelagia noctiluca populations outbreaks is changing under environment and/or climate factors. In this work, we investigated decadal records of population density changes of Pelagia noctiluca size in different Mediterranean areas (Balearic Sea, Gulf of Tunis, North and South Adriatic Sea and Aegean Sea).It seems that the periodicity of outbreaks is about 20 years, but in those areas when Pelagia noctiluca outbreaks, local hydrological and trophic conditions seems to be favourable to maintain high abundance of Pelagia noctiluca for period lasting for more than 10 years. Such recent ecological changes observed in the timing and strenght of Pelagia noctiluca outbreaks appeared related to large - scale atmospheric fluctuations ultimately mediated by the ocean - atmosphere system playing out in the Atlantic Ocean.

Mediterranean; Pelagia noctiluca; outbreaks; climate

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