Various human activities, including fishing, have an impact on marine ecosystems. There are concerns about the impact of these activities on the resilience of ecosystems, that is, on an ecosystems? capacity to continue to support and maintain a balanced, integrated, and adaptive biological community, which has a species composition, diversity and functional organisation comparable to that of similar natural habitats in the region.
This concern has given rise to a societal demand for an ecosystem-based fisheries management (EBFM), which involves the conservation of ecosystem structures, processes and interactions through sustainable use. As ecosystems often straddle jurisdictions there is frequently a need for co-operation between fisheries authorities. About 95% of world marine production originates from coastal ecosystems, such as estuaries, marshes, shallow bays and wetlands, mangroves, coral reefs and sea-grass beds. These play a major role in the life cycle of many marine organisms, including economically important fish species, by providing breeding, nursery and feeding grounds. Degradation of coastal ecosystems often happens as a result of other competing uses of resources, such as land reclamation, drainage, coastal construction and sewage discharge. An ecosystems approach to fisheries management needs to take into account activities other than fishing.
In implementing a plan to conserve ecosystem structures and processes, fishing practices that involve excessive use of resources, or use of fishing gear in a manner or at a location that causes destruction of habitat, or the use of fishing methods that are themselves destructive, need to be stopped in the interest both of conserving the ecosystem and of ensuring optimal productivity in its use. Other issues arise when considering the resilience of ecosystems. They are the extent of the problem of lost or abandoned fishing gear, which can continue to catch fish when no longer under the control of the fisher. Also, improving the selectivity of fishing gear and methods that presently harvest unwanted catch becomes an issue.