Cues from the predator crab Thalamita danae fed different prey can affect scope for growth in the prey mussel Perna viridis

Clearance rate (CR), absorption efficiency (AE), respiration rate, excretion rate and scope for growth (SFG) were investigated in the green-lipped mussel Perna viridis upon exposure to predatory crabs, Thalamita danae, that had been either starved or maintained on diets with P. viridis or shrimp tissue. The CR and SFG were significantly lower when the mussels were exposed to starved T. danae or those fed with mussels. The differences were observed immediately after the mussels were exposed to the cues (Day 0) and 7 days later. The AE, however, was significantly different among treatments on Day 0, with the highest efficiency being obtained for mussels exposed to crabs maintained on shrimp and followed by the control without any predator cues. Results showed that P. viridis was able to discriminate between predators on different diets and adjust physiological responses according to the level of perceived risk, with growth reduced at higher risks.