Welfare Implications of Cetacean Bycatch and Entanglements

Each year, many cetaceans die from accidental capture in fishing gear. Despite intense study in some species, we know little about levels of bycatch and entanglement in most of the world’s fisheries. Existing laws focus on maintenance of populations rather than welfare. Yet bycatch has wide-reaching welfare consequences, affecting quality of life for the many cetaceans that become injured and stressed or suffer the loss of conspecifics. For each that dies, we can expect many more to survive and suffer from such interactions. Our understanding of the welfare implications of cetacean bycatch has increased, but remains poor. As sentient, highly intelligent beings, cetaceans are considered by many to be in the highest category of animals on a scale of sensibility to pain and suffering, in the same category as primates and carnivores. Yet there has been little change in fishery management to reflect this increasing welfare knowledge and, in general, inadequate effort to reduce the numbers of cetaceans caught in gear. The assessment and awareness of welfare implications of bycaught cetaceans is several decades behind farm animal welfare. Pathological data indicate that the majority of bycaught cetaceans asphyxiate. Those that escape or are released from fishing gear can suffer a variety of injuries, high levels of stress, behavioural alterations and physiological and energetic costs that can lead to reduced long-term survival. These, along with wider social implications for conspecifics, are considered, as are ways to understand and reduce bycatch and entanglements.