The importance of the world's marine environment cannot be overstated. Oceans comprise 70% of the earth's surface, and one-half of the world's population lives in close proximity to coastlines (Cicin-Sain 2003). Oceans provide many important ecological functions as well as supporting economic activities. A pioneering study by Costanza et al. (1997), for example, identified 16 ecological functions ranging from nutrient recycling to food production that generate an estimated $21 trillion (1994 US) in economic value from the world's marine environment, a value almost equivalent to the world's total economic output. While the value of the marine environment is undeniably significant, the threats to the ecological health of the marine environment are undeniably severe. One recent comprehensive study of the marine environment, for example, concluded that 41% of marine ecosystems are strongly impacted by human activity and only 4% remain unaffected (Halpern et al. 2008). Three-quarters of the world's fish stocks are fully exploited, overexploited, depleted or recovering from depletion (FAO 2007). Major dead zones are emerging in the world's oceans and the pressures from human impacts are expected to get worse (UNEP 2007).