1. Preface. - 2. Introduction to marine mammal welfare. - 3. Cetacea – whales, dolphins, porpoises. - 3.1 The welfare effects of marine debris and fishery equipment on Cetacea, entanglement, toxicity – and of marine pollution including oil. - 3.2 Bycatch. - 3.3 Welfare impact of loss of habitat, changes in distribution and feeding and reproductive behaviours, and disturbances to migration. - 3.4 The welfare effects on Cetacean of human interactions – noise, boats, exploration, dredging, wind farms, whale watching, hunting. - 3.5 Noise in the ocean. - 3.5 Global climate effects on cetacean welfare. - 3.6 Social change in Cetacean populations resulting from human influences. - 3.7 Cetacea in captivity. - 3.8 Assessing the welfare of Cetacea – outcome based assessment methods in the wild and in captivity. - 4. Pinnipeds – seals, sea lions, fur seals, walrus. - 4.1 The welfare effects on Pinnipeds of marine debris and fisheries equipment, entanglement, toxicity – and of marine pollution including oil. - 4.2 Bycatch. - 4.3 Interactions with farmed fisheries. - 4.4 Welfare impacts of loss of habitat, human induced changes in distribution and feeding and reproductive behaviours, and disturbances to behaviours and social dynamics of Pinnipeds. - 4.5 The welfare effects on Pinnipeds of human interactions – tourism, hunting. - 4.6 Glob al climate effects on Pinniped welfare. - 4.7 Social change in Pinniped populations resulting from human influences. - 4.8 Pinnipeds in captivity. - 4.9 Assessing the welfare of Pinnipeds – in the wild and in captivity. - 5. Sirenia – dugongs and manatees. - 5.1 The welfare effects of human interactions on Manatees and Dugongs – boats, boat strikes, tourism, noise, the coastline as a recreational zone. - 5.2 The welfare effects on Sirenia of marine debris and fisheries equipment, entanglement, toxicity. - 5.3 Welfare impacts of loss of habitat, human induced changes in distribution and feeding and reproductive behaviours, and disturbances to behaviours and social dynamics of Sirenia. - 5.4 Social change in Sirenian populations resulting from human influences. - 5.5 Global climate effects on Sirenian welfare. - 5.6 Sirenia in captivity. - 5.7 Assessing the welfare of Sirenia – in the wild and in captivity. - 6. Ursidae - polar bears. - 6.1 The welfare effects of human interactions – human food and human waste, proximity to habitation, living together with polar bears. - 6.2 The welfare effects on Polar Bears of marine debris, fisheries equipment, entanglement, toxicity. - 6.3 Welfare impacts of loss of habitat, human induced changes in distribution and feeding and reproductive behaviours, and disturbances to behaviours and social dynamics of Polar Bears. - 6.4 Social change in Polar Bear populations resulting from human influences. - 6.5 Global climate effects on Polar Bear welfare. - 6.6 Hunting of Polar Bears. - 6.7 Polar Bears in captivity. - 6.8 Assessing the welfare of Polar Bears – in the wild and in captivity. - 7. Lutrinae – otters. - 7.1 The welfare effects of human interactions on otters – dogs, disturbance, fishing. - 7.2 The welfare effects on Otters of water borne debris, fisheries equipment, entanglement, toxicity. - 7.3 Welfare impacts of loss of habitat, human induced changes in distribution and feeding and reproductive behaviours, and disturbances to behaviours and social dynamics of Otters. - 7.4 Social change in Otters populations resulting from human influences. - 7.5 Global climate effects on Otter welfare. - 7.6 Hunting of Otters. - 7.7 Otters in captivity. - 7.8 Assessing the welfare of Otters – in the wild and in captivity. - 8. Conclusions. - 9. References.