Global food demand is rising, and serious questions remain about whether supply can increase sustainably 1. Land-based expansion is possible but may exacerbate climate change and biodiversity loss, and compromise the delivery of other ecosystem services 2-6. As food from the sea represents only 17% of the current production of edible meat, we ask how much food we can expect the ocean to sustainably produce by 2050. Here we examine the main food-producing sectors in the ocean-wild fisheries, finfish mariculture and bivalve mariculture-to estimate 'sustainable supply curves' that account for ecological, economic, regulatory and technological constraints. We overlay these supply curves with demand scenarios to estimate future seafood production. We find that under our estimated demand shifts and supply scenarios (which account for policy reform and technology improvements), edible food from the sea could increase by 21-44 million tonnes by 2050, a 36-74% increase compared to current yields. This represents 12-25% of the estimated increase in all meat needed to feed 9.8 billion people by 2050. Increases in all three sectors are likely, but are most pronounced for mariculture. Whether these production potentials are realized sustainably will depend on factors such as policy reforms, technological innovation and the extent of future shifts in demand.

International audienceMany countries have actively encouraged the production of biofuels as a low-carbon alternative to the use of fossil fuels in transportation. To what extent do these trends imply a reallocation of scarce land away from food to fuel production? This paper critically reviews the small but growing literature in this area. We find that an increase in biofuel production may have a significant effect on food prices and, in certain parts of the world, in speeding up deforestation through land conversion. However, more research needs to be done to examine the effect of newer generation biofuel technologies that are less land intensive as well as the effect of environmental regulation and trade policies on land-use patterns

We develop a bioeconomic model of a fishery subject to stock uncertainty and price uncertainty. With a linear control model, the optimal harvest policy is a bang-bang approach to the optimal stock level, where one harvests either at minimum or full capacity. It is assumed that changing the harvest rate is subject to a switching cost. In this case we show that there are two switching curves in stock-price space, one for entering and one for leaving the fishery. Numerical methods are used to characterize the optimal switching policy for the fishery.

This article provides a survey of the economic literature on investment behaviour and capacity adJustment in fisheries. An overview of the existing theoretical and the empirical work is provided, and areas that require more work are pointed out. The survey shows that while a large body of theoretical work has been developed on the issue of capital adjustment in fisheries, relatively less attention has been granted to the theory of investment, where this becomes a separate decision to the decision about capital levels; i.e., where capital is quasi-malleable. In addition, empirical studies have been fairly limited, and more work is still needed to analyse and fUrther investigate these issues in practical situations. There is particularly a need for more empirical studies of investment behaviour and drivers of investment behaviour at the firm level based on adequate economic data.