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GEO Year Book 2003  
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OVERFISHING: HARVESTING FISH FASTER THAN THEY CAN REPRODUCE

In 2002, 72 per cent of the world’s marine stocks were being harvested faster than they can reproduce (FAO 2002a) and fishing activities were shown to be having an impact on important, and until recently, unresearched and even undiscovered, marine ecosystems. Major changes in the exploitation and management of marine habitats are needed to avoid many marine fisheries from becoming commercially extinct.

Despite an increase in the reach and intensity of commercial fishing operations and contrary to some official data (see GEO Indicators section), the total quantity of fish catches is estimated to have been declining by about 700 000 tonnes a year since the late 1980s (Watson and Pauly 2001). The initiatives that have been taken for specific fisheries have been ineffective in addressing this downward trend. Alder and Lugten (2002) demonstrated for the North Atlantic that there has been a decline in landings, despite a plethora of agreements which focus on the management of stocks. The measures taken for some species such as tuna may be too little and in some cases, such as for the cod off Newfoundland, possibly too late (Myers and Worm 2003).

Figure 1: Patagonian toothfish (Dissostichus eleginoides)
Source: USDA Regulatory Fish Encyclopedia

Fish stocks that are recovering or rebuilding are generally small, isolated and easily managed, such as the orange roughy stock on New Zealand’s North-east Chatham Rise (Ministry of Fisheries 2003). The gains in abundance are minor compared to other stocks that continue to decline, especially those in the high seas shared among countries (such as the Patagonian toothfish)(Figure 1).
Other changes are taking place. Fishing fleets are venturing farther from their home ports, off the continental shelves and into deeper waters to meet the global demand for fish (Pauly and others 2003). Consequently, fish are being captured from stocks which were previously unexploited and the long-term viability of a number of species may be jeopardized.

Illegal, unregulated and unreported (IUU) fishing has also increased in many areas. Fisheries management is primarily based on landing data: if fish are caught and not recorded in the official statistics then the data (including age, sex and size structure) needed for management are distorted. If stock assessment specialists do not have a good estimate of illegal fishing or account for it in their analysis, the management measures that are recommended may be inappropriate or inadequate. Techniques employed in IUU fishing also go unchecked: gear may be used that damages the marine environment or other, non-targeted, species including seabirds such as the albatross, caught on long-line hooks. In 2003, greater attention was paid to illegal fishing, with many governments increasing their enforcement activities as one of many measures to address the problem of overfishing (FAO 2003a).


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