DISCHARGE from several shrimp farms in Kuala Selangor has polluted neighbouring mangroves swathes and threatens the firefly colony and other marine life there.
The creation of ponds for marine shrimp aquaculture has led to the destruction of thousands of hectares of mangroves and coastal wetlands, not only in Malaysia but the world over.
Mangroves support numerous marine as well as terrestrial species, protect coastlines from storms and erosion and are important in the subsistence of many coastal communities.
Mangroves provide nursery grounds for various young aquatic animals, including commercially important fish, and their destruction can lead to substantial losses for fishermen due to a decline in wild stocks of fish and other marine life.
In Malaysia, at least 65 per cent of fish and shellfish harvested are associated with mangroves, over 30 per cent of shell and fish landed by commercial operators each year are mangrove-dependent, and in some regions, the figure may be as high as 50 per cent.
An estimated 600kg each of finfish and shrimp are produced annually in Malaysia from every hectare of mangrove.
A 2006 report by the United Nations Environment Programme (UNEP) also noted that a 400sq km area of mangrove forest in Matang, Malaysia, support fishery worth US$100 million (RM340million) a year while ecosystem services afforded by mangrove forests in Thailand are worth US$35,000 per hectare.
The Scripps Institution of Oceanography at the University of California at San Diego, after analysing fish landings in 13 regions in the Gulf of California and the Gulf of Mexico, revealed that fish yield was directly proportional to the length of coastline forested with mangroves.
The scientists used the findings to estimate the monetary value of mangroves at US$37,500 per hectare per year.
Nearly irreversible as it is, the destruction of mangrove is all the more deplorable if we consider the fact that a hectare of intensive shrimp farming is profitable for just three to five years, after which it is abandoned and new areas are developed.
Besides this, aquaculture effluents contain a myriad of pollutants.
If untreated, the effluents could cause an increase in the level of suspended solids and nutrients accompanied by a fall in oxygen content.
The effluents can also contain toxins depending on which chemicals are used to disinfect farms, control pests, control predators, antibiotics. etc
Considering the negative impact, aquaculture should not be regarded as a conduit for the development of fisheries in Malayisa because it is not sustainable.
Shrimp farming must be restricted.
We call upon the government to scrap all new development of intensive shrimp farms, including the proposed 1,000ha Integrated Shrimp Aquaculture Park (i-SHARP) in Setiu, Terengganu by Blue Archipelago Bhd, a subsidiary of Khazanah Holdings.
Efforts must also be taken to rehabilitate degraded mangrove areas.