Potentially harmful contact between fisheries and marine vulnerable species represents a global conservation issue and efforts to mitigate the negative repercussions of these interactions belong in strategies for ensuring the sustainability of fisheries. This literature review offers a survey of mitigation measures and techniques that have been developed and tested around the world, aiming to address both the incidental catch of highly mobile species – specifically, cetaceans, seabirds, sharks and rays, and sea turtles – and depredation caused by dolphins. Based on research detailed in over 300 documents, including peer-reviewed publications, reports from international organizations and papers available on the internet, most of the mitigation techniques illustrated are still under development, with only a few already adopted through legislation. The selected mitigation measures are grouped by main types of fishing gear – gillnets and trammel nets, longlines and lines, trawls, purse seines, traps and pots – and further subdivided according to which of the four main groups of vulnerable species – cetaceans, seabirds, sharks and rays, or sea turtles – they are designed to protect. Preventive and curative approaches covering both technical measures (gear modifications, strategies, as well as acoustic, visual, magnetic and chemosensory deterrents) and management measures are described.
This publication gives an updated review of the quantity of discards in the world's marine fisheries, using information from a broad range of fisheries in all continents. A number of policy issues are discussed including a 'no discards' approach to fisheries management, the need for balance between bycatch reduction and bycatch utilisation initiatives, and concerns arising from incidental catches of marine mammals, birds and reptiles. The report also highlights the need for more robust methods of estimating discards, and the development of bycatch management plans.
Marine mammals attract human interest – sometimes this interest is benign or positive – whale watching, conservation programmes for whales, seals, otters, and efforts to clear beaches of marine debris are seen as proactive steps to support these animals. However, there are many forces operating to affect adversely the lives of whales, seals, manatees, otters and polar bears – and this book explores how the welfare of marine mammals has been affected and how they have adapted, moved, responded and sometimes suffered as a result of the changing marine and human world around them. Marine mammal welfare addresses the welfare effects of marine debris, of human traffic in the oceans, of noise, of hunting, of whale watching and tourism, and of some of the less obvious impacts on marine mammals – on their social structures, on their behaviours and migration, and also of the effects on captivity for animals kept in zoos and aquaria. There is much to think and talk about – how marine mammals respond in a world dramatically influenced by man, how are their social structures affected and how is their welfare impacted?