Deep-ocean climate change impacts on habitat, fish and fisheries

This publication focuses on the impacts of climatic changes on demersal fisheries, and the interactions of these fisheries with other species and vulnerable marine ecosystems. The principal cause of climate change is rising greenhouse gases and other compounds in the atmosphere that trap heat causing global warming, leading to deoxygenation and acidification in the oceans. Three-dimensional fully coupled earth system models are used to predict the extent of these changes in the deep oceans at 200–2500 m depth. Trends in changes are identified in many variables, including temperature, pH, oxygen and supply of particulate organic carbon. Regional differences are identified, indicating the complexity of the projections. The responses of various fish and invertebrate species to these changes in the physical environment are analysed using hazard and suitability modelling. Projections are made to changes in distributions of commercial species, though in practice the processes governing population abundance are poorly understood in the deep-sea environment, and predicted distributional changes are not always as expected and may be manifested as simple disappearance of species or ecosystems. The publication highlits that adaptive monitoring and management mechanisms must be in place to ensure that fisheries are sustainable and the environment remains healthy and productive. Suggestions are provided as to the actions necessary.