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New species not a panacea for trading problems

INDONESIA - The Network of Aquaculture Centres in Asia-Pacific (NACA) is warning about the dire effects that introducing 'new shrimp species' can have on biodiversity, fish health and the future profitability of fish farming in the region.

In a recently published report by Sena S. De Silva, C.V. Mohan and Michael J. Phillips, it says that anti-dumping bans, which are common place in global trading due to the oversupply of shrimp, is now encouraging some shrimp-producing nations to look at using new species in a bid to reduce costs, cope with disease problems and compete on the world market.

Dumping, in aquaculture terms, occurs when exporters flood a market with a low priced cultured commodity, at a price which is either below the price in its home market or is below its cost of production.

The report says that although industries do have a forum through the World Trade Organisation aimed at settling disputes, such measures may be deemed useless under a new kind of “dumping” which could occur with the widespread introduction of new species.

Commercial transactions, associated with the introduction of a new species in the Asia-Pacific region, often do not take account of the potential environmental damage and costs to biodiversity that afarming a new species can incurr.

Surprise and concern
At a recent Indonesian aquaculture meeting, Indo Aqua 2007, held in Bali, Indonesia, the report's authors expressed surprised and dimay regarding the promotion of Penaeus stylirostris as a new species for aquaculture. The species was being pushed in view of emerging problems with Penaeus vannamei as it could help some exporting nations get round 'dumping' issues.

NACA says that although economically this may be a good move for producers, long-term it could be very damaging to the environment and to the many other small scale producers that have continued to farm native species. Thes producers have managed to increase productivity and efficiency by improved farming techniques and investment.

It says that the controversial introduction of P. vannamei into certain Asian countries has definitely helped to revive the shrimp aquaculture sector - the indigenous P. monodon had succumbed to various disease problems and producers were experiencing significant difficulties and economic losses.

However, other nations, such as India and Vietnam have resisted the introduction of the new species, but tried hard, and succeeded, to revive their business using native P. monodon, through improved farming practices (Briggs et al, 2004).

However, of greater concern is the impact that P. vannamei may have on the biodiversity of Asia's aquaculture and fisheries sector. Evidence suggests that the species is already present in the wild and yet there is no knowledge of what this will mean for the environmental balance or health of the sector in the long-term.

Disease issues
The NACA says that the region lacks the regular introduction of healthy pathogen free stock (SPF). Broodstock is usually produced in the west and introduced to regional fisheries at the larval stage. But introductions of true SPF broodstock has not always happened in Asia. This is demonstrated by the levels of Taura syndrome virus (TSV), which has been found in countries where P. vannamei production is popular.

In recent years, another exotic viral disease caused by infectious myonecrosis virus (IMNV) has also been reported in the region (NACA/FAO 2006). These disease problems confirm that introductions of exotic species for use in aquaculture, will always carry a risk of introducing exotic pathogens, alongside impacts to biodiversity.

The region has had to cope with WSSV for a long time, and now has to deal with two more dangerous exotic virusesthat have the potential to inflict long term damage on the shrimp industry. The cryptic nature of crustacean viruses and their ability to cause multiple infections raises important issues when considering the trans-boundary movement of crustaceans, including SPF/SPR stocks.

The Regional Aquatic Animal Health Advisory Group of NACA has repeatedly expressed concern about TSV in Asia, especially because the pathogen is spreading and changing genetically. This could lead to changes in virulence, not only in P. vannamei, but also in the susceptibility of local crustacean species. The high number of variants of TSV represents a threat of unknown proportions to native species.

More sustainable
The NACA believes that the Asia-Pacific region need to be more sustainable in producing seed stock. It needs to be less dependent on outside SPF source. It says the solution lies in a consolidated approach; involving the private sector and governments of the shrimp producing nations, who need to invest more substantially in development of SPF broodstock of P. monodon and other local species. Such programs are currently under development in several countries and would benefit long-term productivity and economics.

NACA says that governments in the region need to employ a proper and detailed risk analysis and promote tougher biosecurity measures across the aquaculture sector.
It says that stakeholders must consider a few pertinent issues:

  • Did the introduction of stocks of the alien species P. vannamei (both SPF and non-SPF) provide any long term solutions to the disease problems, or did it in fact make the situation worse by introducing additional pathogens to trouble farmers?
  • Will the introduction of another exotic species to the region do any good?
  • Has the long term impact of P. vannamei on local biodiversity been properly assessed and understood?
  • What prevents us from reviving the native P. monodon industry?

Short term reactive solutions are not the answer becasue the industry involves intricate biological systems, says the NACA. The sector is duty-bound to future generations to preserve biodiversity in ecosystems and not risk them for short term commercial gains. It is regrettable that, although the commercial advantages of the introduction of SFP shrimp are well advertised (eg. Wyban, 2007), the emergence of new diseases in the region associated with the introduction, and or long-term potential impacts on biodiversity are rarely or never addressed, says the NACA.

It fears that some Asian nations will again be drawn into widespread introduction of yet another species of shrimp, with no concerns on long term impacts. NACA’s wants to see greater sustainability of the aquaculture sector in the Asia-Pacific region, and a future for the millions of small scale farmers who make a livelihood from aqua farming. These people provide more than 40 percent of the food fish consumed globally and need protection through a science-based analysis and appropriate management measures not the introduction of yet another new species, that may spread, and lead to unforeseen future problems for the sector and the region’s biodiversity.

Further Reading

- To read the full report click here.