Bioeconomics of ocean acidification effects on fisheries targeting calcifier species: A decision theory approach

The impact of ocean acidification on fisheries is a relatively new issue facing decision-makers, and one for which very little empirical data is available to draw upon. This paper demonstrates how, despite the lack of knowledge, well-established methods of bioeconomic modelling and decision analysis can be applied to address the challenge. A decision support framework is developed, incorporating a dynamic age-structured bioeconomic model together with a set of decision tables applicable in the absence of known probabilities of future change. With such a model it is possible to trace ocean acidification as an additional stressor, specifically on fisheries targeting calcifier species, such as many high value mollusks. We do so by shifting growth and natural mortality parameters into time varying functions of ocean acidity (pH), as forecasted by climate scenarios reported by the Intergovernmental Panel on Climate Change (IPCC). Possible effects of ocean acidification on calcifier species with various life cycles were modeled beginning with initial biological parameters of the growth and mortality dynamic functions reflecting differences in individual growth, natural mortality and species longevity. The analysis illustrates how fishery outcomes depend on the extent of ocean acidification and the life cycle of calcifier species. Results also indicate that under uncertainty, there is value in taking precautionary management measures, such as reducing fishing intensity. (Full Publication)