Assessment of magnesium chloride as an anaesthetic for adult sea urchins (Paracentrotus lividus): incidence on mortality and spawning

摘要

During this study different concentrations of magnesium chloride (MgCl) were tested on adult wild-caught sea urchins (Paracentrotus lividus) immediately after their collection in the field in order to assess whether MgCl can act as an anaesthetic during their transport and prevent unplanned spawning. Such accidental spawning is a stress response associated with transport of this species. The mortality and gonadal indices were recorded after a 1-h submersion in different strength solutions of MgCl (5, 20, 40, 80 and 100 mmol Lp# MgCl), followed by 5 h of dry transport under two different temperatures (19 and 25 pC). The effective concentration of MgCl was defined as one that does not induce mortality and gonad mass loss following sea urchin transport and laboratory conditioning. Treatment of sea urchins with 5 mmol Lp# MgCl prevented mortality and unplanned spawning; however, elevated concentrations of magnesium (40, 80 and 100 mM) were toxic to sea urchins, inducing a massive mortality and gonad mass decrease during the acclimatization period, essentially when sea urchins were transported under an elevated temperature (25 pC). It is concluded that MgCl is a suitable non-toxic anaesthetic, easily available for adult sea urchins (P. lividus) when it is used at its optimal anaesthetizing concentration.