Sustainability Indicator

A sustainability indicator is a measurable metric that tracks progress toward an environmental, social, or economic sustainability goal, condensing complex system state into a value managers and policymakers can act on. In the marine domain, indicators include chlorophyll-a and dissolved oxygen for eutrophication, faecal indicator bacteria for bathing water, and fish-stock biomass relative to maximum sustainable yield. The UN Sustainable Development Goals, adopted in 2015, frame ocean targets under SDG 14 with their own indicator set. OSPAR EcoQOs and the EU Marine Strategy Framework Directive Good Environmental Status descriptors are indicator-based assessment systems. Sound indicators are specific, measurable, policy-relevant, and tied to a reference or target value.