15. Relationships Between Tropical Coastal Habitats and (offshore) Fisheries

The economic welfare and productivity of many tropical fisheries, inshore or offshore, depends on the integrity of coastal habitats, particularly mangroves and coral reefs. Fisheries within coastal systems in developing countries are usually artisanal or subsistence in nature, whereas offshore fisheries are usually commercial or industrial. Relationships between fisheries production and areas of mangrove have been quantified, notably for penaeid prawns, but in most cases the causal links have not been established. Nevertheless, evidence of the value of mangroves to fisheries continues to mount and the importance of the relationship has gained widespread acceptance. Coral reef fisheries are largely the domain of small-scale fishers, but their relative importance is very great with global catches in excess of 2 × 10⁶ tonnes. Their fisheries productivity is less than that of estuarine and coastal waters. The connectivity between reef fisheries and mangroves and seagrasses, and connectivity between reefs are relevant to offshore fisheries. Coral reefs support some pelagic fisheries, such the pole-and-line tuna fleets in the Pacific and Indian Oceans. For most tropical fisheries, the key issue is the depleted state of the resources, e.g., for most tropical Asian countries biomass has declined to <10% of baseline estimates. The major contributor to this is overfishing linked to poverty among fishing communities—symptoms of lack of effective management. Strategies to address the situation relate to ecological connectivity and dependence on mangroves or coral reefs, the balance between small-scale and industrial fisheries, and scales of management as well as use of Marine Protected Areas (MPAs).