Technical guide to collect data related to depredation on board longline vessels

Depredation is an increasing concern in areas where Patagonian toothfish is targeted. In order to assess its effect and understand the process of depredation by killer whales and sperm whales, good quality data needs to be collected at sea. This paper describes the different variables collected by observers within French EEZ (area 58.5.1 and 58.6).