EPHYRA OF AURELIA AURITA JELLYFISH AS A ECOTOXICOLOGICAL MODEL FOR MONITORING QUALITY OF THE SEA-WATER CIRCUIT OF A PUBLIC AQUARIUM.

Gelatinous zooplankton such as the jellyfish (Cnidarian) play an important role in marine food webs both as major consumers of metazooplankton and as prey of apex predators (e.g., tuna, sunfish, sea turtles). Despite its great ecological importance the use of these organisms as biological models for ecotoxicological bioassays is still very poor. For this reason, our research group has recently standardized a protocol for use of the ephyra stage of Scyphozoan jellyfish Aurelia aurita as innovative ecotoxicological model. The aim of this study was to simplify and optimize this new ecotoxicological protocol to propose the ephyrae jellyfish as marine model organism for a monitoring the quality of the sea-water in public and private acquariums. To do that, a series of sequential experiments with ephyrae of Aurelia aurita have been carried out in laboratory in order to investigate the influence of different culturing and methodological parameters (volume and time of exposition, photoperiod, and ephyrae age) on acute (immobility) and behavioural end-point Frequency of Pulsations) and standardize a new bioassy protocol. The new simplified protocol was then compared with the previous one using a well known reference toxic compound (Cadmiun nitrate) in order to analyse the acute (% of immobility) and behavioural (% of Frequency of pulsation) end2 points at different time of exposure (3-6-24 and 48 h) of ephyrae of Aurelia aurita of different age (0-7-14 days). The toxicity tests were performed at the same time for both protocols: the ephyrae were exposed in multiwell plates for the original bioassay and in testtubes for the new simplified protocol developed in this work. Finally with the new protocol have been proposed different strategies for for monitoring of the seawater circuit of the Aquarium of Genoa.