Climate-change resilience and positive scope for growth in wild adult Sydney rock oysters, Saccostrea glomerata (Gould, 1850)

Context Oysters have ecological and economic importance worldwide because they provide ecosystem services and sustain profitable aquaculture industries. Calcifying bivalves including oysters have been found to be sensitive to ocean warming and acidification caused by anthropogenic climate change. Aims This study tested whether adult wild Sydney rock oysters, Saccostrea glomerata, have resilience and can maintain sufficient scope for growth or are pushed into a suboptimal state. Methods Oysters were exposed to elevated pCO2 (335 and 857 μatm) and temperature (24 and 28°C) in an orthogonal design for 5 weeks. At the end of the exposure, growth, condition index, clearance, ingestion and absorption efficiency and rates were measured and scope for growth calculated. Key results Sydney rock oysters responded to elevated pCO2 and temperature with no change in overall growth or condition index, but with significantly increased metabolic, clearance, ingestion, and absorption rates and positive scope for growth. Conclusions Our results indicated that adult S. glomerata can cope with the moderate level of climate-change stress predicted for 2100, through increased standard metabolic rate and increased energetic processes. Implications If food availability becomes limiting, and other environmental stressors interact with climate change stressors, then resilience thresholds maybe breached for this economically, ecologically and indigenous significant and iconic oyster species.