Field predation and non-predatory mortality rates

Calculated predation rates from a caging study on Macoma balthica in the York River in 2006. Rates were calculated based on the number of marked clams recovered after approximately 4 weeks exposure time. Non-predatory mortality rates were based on the recovery of marked dead clams (i.e. undamaged shells). The major predator on M. balthica in this system is the blue crab Callinectes sapidus.