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Únicamente la versión en inglés ha sido aprobada por el Comité Científico de GreenFacts.
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3. What is the state of fishery resources?
- 3.1 What is the state of marine fisheries?
- 3.2 How are fishery catches changing?
- 3.3 How may fisheries management affect sustainable development?
- 3.4 What is the state of inland fisheries?
3.1 What is the state of marine fisheries?
After increasing from around 79 million tonnes in 1998 to 87 million tonnes in 2000, world marine capture fisheries production decreased to around 84 million tonnes in 2001 and remained at that level in 2002. This decrease mostly took place in the Southeast Pacific and the Northwest Pacific.
For specific data on the trends in fisheries resources in different regions of the Pacific, Atlantic, and Indian Oceans, click on the map below:
Monitoring the status of fisheries can be difficult in regions where statistics collection is poor. This leads to a relatively high proportion of catches being reported as “miscellaneous marine fishes”. This is a significant problem for monitoring the status of fisheries in the Indian Ocean as well as in other areas such as the Southwest, Eastern and Western Central Atlantic, and the Northwest and Western Central Pacific.
Fisheries production in the high seas is highest in the Pacific, followed by the Atlantic and the Indian Oceans. Tunas are the single most important resource exploited in the high seas. More...
3.2 How are fishery catches changing?
In some areas a proportion of the traditional marine fishery stocks have been depleted. As a consequence, other (less-valuable and previously less-exploited or non-exploited) species are being targeted. This has resulted in a long term change in catch composition. In the Northeast Atlantic, for instance, the continuous decline in cod catches since the late 1960s has been counterbalanced by increasing catches of formerly low-valued fish species such as blue whiting and sand eels.
The general trends in the levels of exploitation of world marine stocks observed in previous years are continuing. In 2003,
- about one-quarter of the stocks monitored were underexploited or moderately exploited,
- about half of the stocks were fully exploited and close to their maximum sustainable limits of exploitation, and
- about one-quarter of stocks were overexploited, depleted, or recovering from depletion, and needed rebuilding.
Of the top ten species in terms of quantity (Figure 6
In 12 of the 16 FAO statistical regions, at least 70% of stocks are already fully exploited or overexploited, suggesting that the maximum marine fishing potential has been reached and that more cautious and restrictive management measures are needed. All the information available tends to confirm FAO estimates that the global maximum potential for marine capture fisheries is about 100 million tonnes, of which probably only 80 million tonnes can realistically be achieved. More...
3.3 How may fisheries management affect sustainable development?
Fishery policies and management have usually focussed on single fishery stocks. In response to worldwide public concerns about ecosystems, there is an increasing demand for better understanding and monitoring of a wide range of processes that affect or are affected by fisheries.
Some of the most important management concerns today are:
- the effects of fisheries on habitats, marine communities, and ecological interactions,
- the effects of land-based activities and climatic changes on fisheries, and
- the lack of selectivity in many fisheries, resulting in bycatch and discards.
Variations in marine ecosystems and fish populations can be due to coastal developments, industrial activities, periodic climatic phenomena (such as El Niño), or longer-term natural climatic cycles.
The effect of climate on fisheries is exacerbated in a situation of overfishing. The assessment of the interactions between ecosystems and fisheries is still in its infancy. Much more needs to be known about the effects of such interactions and about how they should be handled and adapted to.
The current state of marine fishery resources and ecosystems allows little room for further delay in taking management measures that should have been taken in the last three decades. Therefore, the precautionary approach to fisheries recommended by various UN bodies and the FAO Code of Conduct for Responsible Fisheries needs to be put into practice. More...
3.4 What is the state of inland fisheries?
Inland fish stocks are less well defined, both in terms of species as well as geographical area, than the major marine fish stocks.
Because of the many different areas in which inland fish stocks live, such as individual lakes, rice fields, or rivers, it is costly to monitor their exploitation and status, and very few countries can afford to do so. The majority of countries report only a small fraction of their inland fishery catches by species, which makes it even more difficult to assess the overall status of these resources.
The trend of inland fishery resources being undervalued and under threat from unsustainable fishing activities as well as habitat alteration and degradation seems to continue.
In general, the availability of global information on river fisheries is poor. Over 50% of inland fish species live in rivers, as does a high proportion of organisms classified as endangered or threatened. Many river basins, especially in developing countries, support intensive fisheries, and in many cases catches are increasing. In some cases, such as in the Mekong River or in Lake Victoria, there is evidence of overfishing and a decline in catches. Sturgeon fisheries in the countries surrounding the Caspian Sea have also decreased drastically since 1988. Inland fishes are considered to be the most threatened group among all the vertebrates used by humans.
The status of certain inland fishery resources has nevertheless been enhanced in many areas through stocking programmes, the introduction of alien species, and habitat engineering and improvement. In many developing areas, especially in Asia, rice fields and irrigated areas are used to grow fish, which can improve the diet of rural households. Enhancement can make the resources more stable, easily harvested, and valuable. More...
