A non-invasive anaesthetic method for accessing the brood chamber of the Chilean flat oyster (Ostrea chilensis)

作者：Alipia T T; Mae H; Dunphy B J^*

来源：New Zealand Journal of Marine and Freshwater Research, 2014, 48(3): 350-355.

DOI：10.1080/00288330.2014.909505

• anaesthetisation
• AQUI-S (R)
• logistic regression
• MgCl2
• mortality

A cost effective method to discern brooding from non-brooding specimens of the Chilean flat oyster (Ostrea chilensis Phillipi, 1844) is needed to optimise current hatchery practices for this species. Accordingly, we investigated the efficacy of two treatments, AQUI-S (R) and MgCl2, in anaesthetising individuals of this species and then mapped any subsequent mortality of anaesthetised oysters. Oysters immersed for 3 h in solutions of 20, 40, 80 and 100 mu L L-1 of AQUI-S (R) exhibited no signs of anaesthesia and also recorded low levels of mortality (i.e. 8% or less). Conversely, oysters immersed in 30, 40 and 50 g L-1 MgCl2 showed between 96%-100% anaesthesia after 3 h whereas only 70% of oysters immersed in 60 g L-1 MgCl2 were anaesthetised over this time period. Time taken for 50% of oyster shells to open (SO50) was compared among MgCl2 treatments with oysters immersed in 60 g L-1 taking significantly longer than (103 min) those immersed in 30-50 g L-1 (SO50 values of 43, 54 and 37 min respectively). Furthermore, treating oysters with MgCl2 resulted in low levels of mortality (i.e. 13% or less) and was not related to MgCl2 concentration. Thus, our results show that immersing O. chilensis in MgCl2 to be an efficient and cost effective method to access the brood chamber of this species. We recommend the use of 30 g L-1 for routine anaesthesia and recommend that future work investigates the efficacy of cheaper MgCl2 sources and what effects MgCl2 anaesthetisation has on developing larvae.

• 出版日期2014