Aquaculture Europe 2023

September 18 - 21, 2023


Add To Calendar 20/09/2023 12:00:0020/09/2023 12:15:00Europe/ViennaAquaculture Europe 2023METABOLIC RESPONSE OF GREENSHELL™  MUSSELS Perna canaliculus IN RESPONSES TO VARIABLE TEMPERATURES, OXYGEN LEVELS AND ANAESTHETICS — IMPLICATION FOR SEAFOOD LIVE TRANSPORTSchubert 4The European Aquaculture Societywebmaster@aquaeas.orgfalseDD/MM/YYYYaaVZHLXMfzTRLzDrHmAi181982


 M. Cheng1,2* ,  L. Zamora2 ,  N. Ragg 2 ,  A. Hickey1 ,  B. Dunphy1


 1  University of Auckland, Private Bag 92019, Auckland, 1142 (New Zealand)

 2 Cawthron Institute, Private Bag 2, Nelson 7042 (New Zealand)

*E- mail:



L ive transport  has  great potential  to  maintain  the  quality  of cultured seafood (Fotedar & Evans, 2011).  The live transport approach, however, involves different handling processes, which  in  mussels could cause stress and mortality (Nguyen et al., 2020) . By inducing metabolic depression before transport, live mussels may be less sensitive to stress caused by handling processes associated with live transport .  In this study,  conditions that  trigger metabolic depression were explored using  a commercially important green- lipped mussel, Perna canaliculus, as a model species, by measurement of cardiac activity.

Materials and methods

 Mussels were exposed to different  treatments i.e., temperature (4°C, 6°C, 8°C and 14°C (control)), oxygen level (0.5mgO2L-1, 1mgO2L-1, 3mgO2L-1  and 8mgO2L-1 (control)) and anaesthetic concentration (MgCl2; 0gL-1  (control), 30gL-1 , 40gL-1 and 50gL-1) for two hours.  During the exposure,  eight  mussels  from each  treatment  were sampled at two time points (i.e., 30 minutes and 120 minutes after the exposure started) respectively  for measurement of heartbeat  (bpm) for 20 minutes.


 Linear mixed-effects  models showed that temperature, oxygen level and MgCl2 concentration,  and the exposure duration had  an  interactive effect  (p < 0.05) on mussel HR (Figure 1). HR of mussels at low temperatures  was depressed by 50–100%, whereas HRs of mussels exposed to MgCl2 decreased by 36–97%. Low oxygen levels only dropped mussels’ HRs by 1.5–51%.


Depression of metabolic rate was most pronounced in the temperature and MgCl2 treatments. Reasons explaining this finding are body temperature of ectothermic organisms depends on the environmental temperature, which governs the biochemical reactions and, subsequently, metabolism and performance within thermal tolerance windows (Cheng et al., 2018). Decreased body temperature due to dropping environmental temperature could reduce ectotherms’ enzyme activity level and thus reduce metabolism, which could be indicated by depressed physiological rates such as respiration and heart rates (Schulte, 2015).  Bivalves can  also  depress their metabolism by shifting from aerobic to anaerobic metabolism to tolerate prolonged hypoxic conditions (Stevens & Gobler , 2018), which was also demonstrated by depressed HRs of P. canaliculus at 0.5mgO2L-1 over exposure time. Immersion in MgCl2 solution could  relax the heart and adductor muscles of P. canaliculus, resulting in reduced HRs as Mg2+ blocks Ca2+ from entering the cell,  which obstruct the  release of  acetylcholine to initiate muscle contraction (Azizan et al., 2021 ; Namba et al., 1995).

By comparison , low temperature and immersion in MgCl2 solution both successfully induced metabolic depression of mussel P. canaliculus. Studies on conditions in  the combination of low temperature and MgCl2 should be explored to see if they will further suppress mussels’ metabolism.


Azizan, A., Alfaro, A.C., Young, T., & Venter, L. (2021). Beyond relaxed: magnesium chloride anaesthesia alters the circulatory metabolome of a marine mollusc (Perna canaliculus ). Metabolomics, 17 (8), 73.

Cheng, M.C., Sarà, G., & Williams, G. A. (2018). Combined effects of thermal conditions and food availability on thermal tolerance of the marine bivalve, Perna viridis. Journal of thermal biology, 78, 270-276.

 Fotedar, S., & Evans, L. (2011). Health management during handling and live transport of crustaceans: A review. Journal of Invertebrate Pathology , 106(1), 143–152.

 Namba, K., Kobayashi, M., Aida, S., Uematsu, K., Yoshida, M., Kondo, Y., & Miyata, Y. (1995). Persistent relaxation of the adductor muscle of oyster Crassostrea gigas induced by magnesium ion. Fisheries Science , 61(2), 241–244.

Nguyen, T.V., Ragg, N.L., Alfaro, A.C., & Zamora, L.N. (2020). Physiological stress associated with mechanical harvesting and transport of cultured mussels (Perna canaliculus): A metabolomics approach. Aquaculture, 529, 735657.

 Schulte, P.M. (2015). The effects of temperature on aerobic metabolism: Towards a mechanistic understanding of the responses of ectotherms to a changing  environment. Journal of Experimental Biology , 218(12), 1856–1866.

 Stevens, A.M., & Gobler, C. J. (2018). Interactive effects of acidification, hypoxia, and thermal stress on growth, respiration, and survival of four North Atlantic bivalves. Marine Ecology Progress Series , 604, 143–161.