Aquatic biodiversity

Despite fluctuations in supply and demand, caused by the changing state of fisheries resources, the economic climate and environmental conditions, fisheries and aquaculture remain very important as a source of food, employment and revenue in many countries and communities. The types of aquatic ecosystems commonly used by capture fisheries and aquaculture are the following:

Inland waters: Fishes and other aquatic resources are captured from a great variety of freshwater ecosystems, including lakes, swamps, rice fields and floodplains, and rivers and streams, most of which are natural. The status and trends of aquatic ecosystems, are closely linked to the condition of adjacent terrestrial ecosystems. Nearly all inland water bodies, however, have been modified to some extent through human intervention (e.g. the enriching effects of excess fertilisers and livestock wastes) and are further transformed in their particular community structures by biodiversity - through the introduction of new species - and by periodic stocking. Therefore, it is essential to view each inland aquatic ecosystem in terms of the watershed, or basin, in which it occurs.

Coastal waters (including estuaries and lagoons) constitute the interface between the marine and the freshwater environments, and between the continents and the oceans. They play a key role as nursery grounds for a wide range of marine species.

Coral reefs are the dominant type of ecosystem in tropical areas with low upwelling or freshwater inputs. Vital for island countries, they are fragile, rich in biodiversity and heavily impacted by inland runoffs and inland activities.

Soft-bottom continental shelves appear in front of major river systems and deltas from which they receive their characteristic fine sediments (e.g. gravel, sand and mud). Extending up to a depth of 200 metres, they are usually strongly influenced by the riverine effluents from which they draw their high productivity and which govern their natural variability.

Upwelling continental shelves are very productive continental shelves found mostly at the eastern boundaries of the oceans, often in front of arid zones or deserts. These ecosystems are affected by strong inter-annual variability (e.g. El Niño and La Niña). They represent areas of especially high concentrations of small pelagic species.

Open oceans represent the largest area and volume of marine ecosystems, although their biological and fisheries production per unit of area is far less than the other ecosystems. Seamounts are noticeable elements of the open ocean ecosystem and host some long-living and fragile deep-sea resources (e.g. orange roughies).

Polar oceans (i.e. the Arctic and Antarctic oceans) are particular, highly-productive ecosystems with great seasonality, characterised by active, current-driven, enrichment processes that sustain important fishery resources (e.g. fish, krill, whales, small cetaceans) and other species (e.g. seabirds, seals).

FAO and aquatic biodiversity

Aquatic biodiversity is being threatened by factors within the fisheries sector, such as overfishing, destructive fishing practices, introduction of alien species, and by external factors such as habitat loss and degradation mainly caused by land-based activities. In recognition that sustainable management is urgently needed for marine fish stocks, the Reykjavik Conference on Responsible Fisheries in the Marine Ecosystem was convened in October 2001. It covered in depth analysis on important global issues relating to the implementation of the Code of Conduct for Responsible Fisheries and reflects the need to link ecosystem considerations in capture fisheries management practices and procedures.

The FAO Fisheries Department is carrying out a variety of activities in relation to aquatic biodiversity that is considered to be an essential prerequisite for sustainable fisheries and aquaculture. The 1982 United Nations Convention on the Law of the Sea (1982) and the FAO Code of Conduct for Responsible Fisheries (1995) provide the umbrella for FAO’s work in fisheries. The Code, in particular, seeks to promote greater order in fisheries and aquaculture and to prevent further resource and environmental degradation. The instrument touches, to some extent, all activities in the fisheries sector. In many countries, the application of the Code of Conduct for Responsible Fisheries is highly dependent on availability and access to technical and policy information, on both fisheries and environmental matters. FAO accords highest priority to providing and enhancing major information resources - including facts and data, strategic advice and facilitated networking for sustainable world fisheries - through the development and promotion of databases, knowledge and information systems.

The Fisheries Department publishes biennially the State of the World's Fisheries and Aquaculture (SOFIA) which aims to provide policy-makers, civil society and those who derive their livelihood from the sector a comprehensive, objective and global view of capture fisheries and aquaculture, including associated policy issues.

For more information on FAO's activities on aquatic biodiversity, please visit the fisheries website.