Seascapes of fear: evaluating sublethal predator effects experienced and generated by marine mammals

The notion that predators can affect their prey without killing them is widely supported in the ecological literature yet rarely applied by marine mammal studies. We present three case studies in which patterns of time allocation by individual marine mammal foragers were used to index the sublethal effects of predators on bottlenose dolphins (Tursiops sp.), harbor seals (Phoca vitulina), and dugongs (Dugong dugon). In each case, foraging individuals optimized energy gain and safety from predators by spending less time in more profitable but dangerous patches or decreasing their use of risky feeding tactics that would increase net energy gain. By implication, marine mammals are subject to the non consumptive effects of their predators (i.e., to intimidation), and fear can mediate their impacts on their resources. We suggest, therefore, that future studies quantify patterns of time allocation to measure sublethal effects of predators on marine mammals, as well as the capacity of