Depredation, the removal of fish from longlines by large marine predators, has been observed throughout the CCAMLR management area. Loss of fish through depredation can cause financial loss to the toothfish fishing industry and if not considered appropriately may lead to a bias in stock assessments through the underestimation of total mortality resulting from fishing and depredation combined. In some CCAMLR subareas this occurrence is well studied and included into stock assessments, while in other subareas the problem is known but not currently addressed. The areas in which the establishment of depredation has been studied have trialled a range of mitigation methods and developed approaches to minimize fishery-mammal interactions. This review summarises the current state of knowledge on depredation development and its impact on stock assessment, and concentrates on the four subareas that have either depredation occurring regularly or only sporadically but have the potential for development of a depredation situation, and could thus benefit of the methods and approaches tested in other subareas.
Dr Chris Darby