New Era

WINDHOEK - Reducing fishing capacity and limiting access to shrimp fisheries are likely to mitigate over-fishing, by-catch and seabed destruction, which the Food and Agriculture Organisation of the United Nations said are some of the major economic and environmental side effects of shrimp fishing.

In the cash- and food-crunch being experienced worldwide, shrimp fishing provides an essential source of cash and employment. However, Jeremy Turner, chief of the Food and Agriculture Organisation (FAO) Technology Service said, against the backdrop of ever-decreasing fishing resources due to global warming and related environmental concerns, shrimp fishing is also associated with over-fishing, the capture of juveniles of ecologically important and economically valuable species, coastal habitat degradation, illegal trawling, and the destruction of sea-grass beds.

Although commercial shrimp fishing operations experience low profitability due to the global economic slowdown, shrimp is considered to be the most important trade fish commodity internationally in terms of value, with a world shrimp catch of 3.4 million tonnes per year, and a world production of shrimp - both captured (constituting 60 percent) and farmed (40 percent) - at about six million tonnes. China and four other Asian countries are said to account for 55 percent of the world catch.

Although over 100 countries export substantial quantities of shrimp, the international shrimp market is concentrated in the US, Japan and Europe.

Shrimp and prawns are said to be some of the most important internationally traded fishery products, valued at about US$10 billion, or 16 percent of global fishery exports.

But the FAO thinks it is important to reconcile the economic importance of shrimp with concerns about the environmental impact of shrimp fisheries.

"With a precautionary and ecosystem approach, many of the problems caused by shrimp fishing can be mitigated," said Turner.

"Shrimp fishing, including shrimp trawling is certainly manageable. Promoting sustainable shrimp fishing management schemes, reducing fishing capacity and addressing the issue of open access are crucial to offer shrimp fisheries a secure future."

A very recent study issued by FAO in 10 countries - Australia, Cambodia, Indonesia, Kuwait, Madagascar, Mexico, Nigeria, Norway, Trinidad and Tobago, and the US - has shown that in many countries, weak agencies dealing with fisheries, lack of political will and inadequate legal foundations have caused failures in the management of shrimp fisheries, and hence environmental management.

For centuries, shrimp has been caught with traditional gear in small-scale fishing like stow nets (China), lift nets, push nets gillnets (Indonesia), barriers across estuaries (Mexico) and nets, weirs and traps (Madagascar).
But industrialised shrimp fishing has brought in mechanised trawling - now estimated to amount to about 140Â 000 trawlers worldwide.

Estimates are that shrimp trawl fishing, particularly in tropical regions, produces large amounts - if not the greatest amount - of discards, or 27.3 percent (1.86 million tonnes) of discards.

The environmental impact of trawling - and including shrimp trawling - has been likened to forest clear-cutting and accused of being the world's most wasteful fishing practice.

By-catch is considered one of the most critical and controversial aspects of shrimp fishing. By-catch, and what is discarded, is a serious conservation problem. The FAO stated that by-catch becomes a serious problem when living resources are wasted, populations of endangered and rare species are threatened, and fish stocks already heavily exploited are further impacted.

By-catch often includes the catch of juveniles of important commercial species such as cod, rockfish, king mackerel, as well as sea turtles.

Important about by-catch, continued the FAO, is that there is often a lack of identification of species killed and rejected, and hence raises the risk of depletion or outright extinction of certain species.

Although a remarkable reduction in shrimp by-catch from large - and medium-scale shrimp factories have been reported, it is still found difficult to determine the levels of by-catch, and said FAO, economic incentives do not necessarily favour by-catch reductions.

Equally, shrimp trawlers not only remove fish biomass, said the FAO, but it also damage local people's fishing gear that often sustains their livelihood, which is the source of constant and intense antagonism.

The FAO further established three types of over-fishing related to the shrimp industry. First, shrimp is harvested when individual shrimps are small and growth not yet completed. This leads to a loss in total yield, and this type of over-fishing is said to be common in many of the world's shrimp fisheries.

Second, spawning biomass and recruitment to the exploitable stock become reduced because of the level of fishing. This type of over-fishing is considered particularly difficult to identify in shrimp fisheries where the relation is blurred by significant environmental effects.

And third, economic over-fishing is as a result of the amount of fishing efforts that increase to the point where fisheries operate beyond maximum economic yields.

Physical impacts and other ecosystem damage are being tentatively controlled by restrictions on certain trawling gear, the areas in which fishing is allowed, and reductions in fishing. Total bans on trawlers have been proposed and adopted, as in the General Fisheries Commission for the Mediterranean, where the banning of trawling beyond 1Â 000 metres reduces the impact on deep-sea shrimp populations and habitats.

Trawling bans are often promoted by environmental groups and have reportedly been implemented occasionally in the past. But the high profitability of trawling and the push for increased landings make the enforcement of bans near impossible.

According to FAO, an ecosystem approach to shrimp fisheries might be needed.

Such an approach means taking careful account of the condition of the ecosystems that may affect fish stocks and their productivity. It further involves taking into consideration the way that fishing activities may affect marine ecosystems.

"This means, where necessary - for example within agreed levels of impact - changing the way in which the fishery operates, adjusting the type of gear used, or imposing closed areas to protect biodiversity or habitats critical to the whole fishery or to the biodiversity of the region," the FAO said.

It also means taking an inclusive approach to setting goals for harvested fish and the fish ecosystem, recognising ecosystem interactions, possibly integrating activities across a range of other users and resource sectors, and respecting the broad range of values for the marine environment.

"An ecosystem approach is perhaps particularly appropriate for the management of shrimp because of its important role as prey in most ecosystems; its sensitivity to climatic factors as drivers of its life cycle and recruitment success; its sensitivity to the quality of coastal habitat; its impact on other fisheries through by-catch; and the potential impact of trawling on the bottom and bottom fauna," the FAO said.

The FAO will release its biennial report, The State of World Fisheries and Aquaculture, on March 2.

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