Ocean acidification increases the vulnerability of native oysters to predation by invasive snails

• Main Authors: Sanford, Eric, Gaylord, Brian, Hettinger, Annaliese, Lenz, Elizabeth A, Meyer, Kirstin, Hill, Tessa M
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: eScholarship, University of California 2014
• Subjects: Life Below Water; Animals; Female; Introduced Species; Larva; Oceans and Seas; Ostreidae; Population Dynamics; Predatory Behavior; Seawater; Snails; climate change; carbon dioxide; invasive species; multiple stressors; ocean acidification; predator-prey interaction; predator–prey interaction; Biological Sciences; Agricultural and Veterinary Sciences; Medical and Health Sciences; Ocean acidification
• Online Access: https://escholarship.org/uc/item/16v5687w

There is growing concern that global environmental change might exacerbate the ecological impacts of invasive species by increasing their per capita effects on native species. However, the mechanisms underlying such shifts in interaction strength are poorly understood. Here, we test whether ocean acidification, driven by elevated seawater pCO₂, increases the susceptibility of native Olympia oysters to predation by invasive snails. Oysters raised under elevated pCO₂ experienced a 20% increase in drilling predation. When presented alongside control oysters in a choice experiment, 48% more high-CO₂ oysters were consumed. The invasive snails were tolerant of elevated CO₂ with no change in feeding behaviour. Oysters raised under acidified conditions did not have thinner shells, but were 29-40% smaller than control oysters, and these smaller individuals were consumed at disproportionately greater rates. Reduction in prey size is a common response to environmental stress that may drive increasing per capita effects of stress-tolerant invasive predators.