The mystery of the aquadeaths

  • 14/05/1995

The mystery of the aquadeaths THE shrimp: a tiny key to a giant treasure chest. A global market -- worth US $8,000 million, 20 per cent of the global seafood trade -- lay open to shrimp farmers from all along India's 7,000 km coastline. The golden egg is the tiger shrimp (Penaeus monodon) gourmandised the world over, priced at between Rs 260-Rs 300 per kg.

This was last year. Then, in September 1994, a mysterious disease wiped out the entire year's crop. It is only when the magnitude of the losses came to light -- Rs 200 crores sank without a trace -- that the Indian government and environmentalists suddenly woke up to the environmental costs of unbridled avarice.

On March 27, the Supreme Court (SC) directed the National Environment Engineering Institute (neeri), Nagpur, to investigate the environmental impact of large shrimp farms in coastal Andhra Pradesh and Tamil Nadu. Union environment minister Kamal Nath recently promised anti-aquaculture activists in Orissa that environment impact assessments (EIA) for shrimp farms would be made mandatory. The Fisheries Department has already issued the Revised Draft Guidelines (RDG) for Sustainable Development and Management of Aquaculture, which is being circulated for comments; virtually simultaneously, the Tamil Nadu Assembly passed a legislation in March to step on the brakes on shrimp farms.

Over the past 3 years, boosted by a liberal exim policy, shrimp farming went feverish and unpoliced. Entrepreneurs incautiously pursued the target of 8-11 tonnes of shrimp per hectare crop (t/ha/crop). They jampacked their shallow ponds with millions of shrimp seeds (larvae), forcefeeding them with imported nutrients.

The plump harvest left behind ponds choked with excess feed, nutrients, fertilisers, dead algae and shrimp shells. This debris was dumped into the nearest waterbody, which often turned out to be water sources for neighbouring farms. And then the virus struck in Andhra Pradesh and Tamil Nadu.

Almost 2 years ago, assistant commissioner of fisheries, V Sampat, had told Down To Earth, "Careless intensive culture could bring about doom, as it did in other South Asian countries." (see box History repeats). The deputy director of Marine Products Export Development Authority (mpeda), K K Chandran, had warned, "The industry needs self-regulation." Even when the viral disease first showed up, the dollar-happy entrepreneurs ignored the mpeda's 4 warning notes urging a voluntary crop-holiday.

"We could have hiked the annual cultured shrimp production from 63,000 tonnes to 200,000 tonnes in 3 to 5 years, but for the disease," says Sakthivel, founder-president of the Aquaculture Foundation of India (AFI) and former head of the mpeda.

Another disease -- mad competition -- finished off the little the virus had left intact. Shrimp farmers tried to best each other: the uncontrolled competition rendered groundwater saline, aggravated negative health factors and social tensions. On January 16, police firing claimed 2 lives in Aduan, a fishing village in Orissa's Bhadrak district. Even now, clashes between aquaculturists and local villagers continue in Tamil Nadu's Nagai-Quaid-e-Millat district.

neeri has already done an environmental study for mpeda, and suggested technical safeguards. The Swaminathan Foundation, Madras, has begun a socioeconomic and scientific study for a sustainable pisciculture alternative. At the National Workshop on Transfer of Technology for Sustainable Shrimp Farming, held in Madras between January 9-15, the Central Institute of Brackish Water Aquaculture (CIBA) director, K Alagarswamy, said: "The cardinal principles of sustainable development are social acceptability, equitability, economic viability, technical appropriateness, environment soundness and conservation of resources."

Traditional brackish water prawn farming, often done in alternating cycles with paddy cultivation, is a century-old practice in coastal Kerala (see box Some never learn) Karnataka, West Bengal and Goa. By the mid-'70s, the government had stepped into scientific culture. icar started research projects and set up a field centre at Narakkal village, under the Cochin-based Central Marine Fisheries Research Institute, which did pioneering investigations into shrimp breeding and seed production.

In 1987, Hindustan Lever's Sandeshkali unit (West Bengal) achieved the 3.5 t/ha/crop target, and was promptly overtaken by Victory Aquafarm's (Tuticorin) 8 t/ha/crop. Big players like Rank Aqua, India Tobacco Company (ITC), Sriram and the Thapar group jumped into the fray. International giants like the Thai Chareon Pokaphand (CP) group tied up with Indian firms. The mpeda and the National Bank for Agricultural Reconstruction and Development (NABARD) and local fisheries departments offered generous loans to small entrepreneurs, who became richer by the day.

In 1992-93, 74,400 tonnes of frozen shrimp fetched forex worth US $410.72 million. Shrimp made for 35 per cent by quantity and 67 per cent by value of the country's total marine food exports. By 1993-94, the shrimp's share in marine food products dropped to 30 per cent by volume -- and yet made for 74 per cent by value. A whopping 2.24 lakh tonnes fetched Rs 2,320 crores.

Semi-intensive farms have mushroomed around Buckingham canal and Kandarelu creek in Nellore, Andhra Pradesh, the Bhadrak-Balasore belt in Orissa, Nagai-Quaid-e-Millat and Tuticorin Tamil Nadu. There are similar belts in Maharashtra and Gujarat.

Of the 1.2 million ha of brackish water areas -- including ponds, lakes and lagoons -- spread along the coastline, about 80,000 ha is under shrimp culture: 80 per cent is under traditional/extensive methods (400-500 kg/ha/crop) and the rest under modified extensive (1-2.5 tonnes/ha/crop) and semi-intensive (5-8 tonnes/ha/crop) modes. These brackish water farms produce 62,000 tonnes a year, 30 per cent of the country's shrimp production. Tiger shrimp (P monodon) and white shrimp (P indicus) are the farmers' mainstay, with species like P japanicus on the fringes.

Semi-intensive requires loads of organic and chemical inputs. At the end of the harvest, the flushed out waste becomes a "pollution shock" for the receiving waterbody -- often a brackish water canal, coastline or creek. In Nellore, the Kandarelu Creek and the Buckingham canal are both victims and the source of water for many shrimp farms.

The seafacing bank of the Buckingham canal is dotted with effluent outlets and inlets, often cheek by jowl. At the canal bank, less than 5 metres from the black sludge-lined effluent outlet of an aquafarm, bent inlet pipes suck in water for the next pond in the serious. The farms here, except the 8 major operators who have personal intake jetties on the sea, feed from the canal; only the big and medium farms chlorinate their water. Says R Ponnuchamy, technical director of Indo Aquatic Ltd, "The Buckingham canal and Kandarelu creek, which simultaneously supply water and receive waste, have become resource pools of infection."

Inputs for disaster
What are shrimp farm effluents made of? The intake water is purified by filtration, sedimentation and chlorination. In the larger farms, oxygen is supplied by aerators: simple floating, paddle-wheel contraptions that churn up the water, mixing air and water. Antibiotics and pesticides keep infections at bay. The salinity level is steadied at 15-20 ppt (parts per thousand) by pumping in water from the sea, creek or canal and mixing it with groundwater.

If a pond bed is acidic, lime is added to neutralise it. Says R K Rath, reader in the aquaculture department of Orissa University of Agriculture and Technology (OUAT): "Zeolytes (magnesium aluminium suphate) are often used to reduce the quantity of suspended solids in ponds water. To help phytoplanktons grow in the ponds, nitrogen-phosphorus-potassium fertilisers are added."

Shrimps thrive on a high-protein diet. "The nourishing part is polyunsaturated fatty acids," says Rath. Trashed fish and shrimp heads make cheap local alternate ingredients. Traditional farmers use chicken and pig excreta.

Scientific feed manufacturing is a complex process. "There are 32 ingredients like shark liver oil, soyabean oil and fishmeal to make various varieties of feed, 28 of which have to be imported," explains K Krishnakumar, a technical manager in a feed factory, Waterbase Ltd.

With so much overload, it was but time before the system blew a fuse. neeri studies suggest that "around 2/3rd of the food supplied is not consumed". As Alagarswamy points out, "The environment responded with a negative feedback due to a self-pollution effect, leading to disease outbreaks."

The culprit is "hypernutrification" (excessive deposit of chemical nutrients), and the inevitable "eutrophication" (increase in phytoplankton), explains K V Ramanamurthy, professor in the Department of Marine Living Resources of the Andhra Pradesh University.

Ramanamurthy adds, "High levels of nutrients can cause blooms of toxic species which may kill fish." These blooms can also deplete dissolved oxygen, increasing the levels of dissolved organic matter, causing an increase in the number of microorganisms, especially bacteria."

The industry is unrepentant: "Compared to domestic wastes our effluents are harmless," says a source. But the fact is that often the waterbody that receives the pollution load is also the source of livelihood for the immediate neighbour. Under such stress, prawns become vulnerable to viral attacks.

The viral disease flared up in the east coast ponds during the last quarter of 1994. It spread like wildfire into Orissa, Andhra Pradesh and parts of Tamil Nadu, selectively decimating tiger prawns. In Nellore, rows upon rows of empty ponds are now on a forced crop holiday.

The site manager of the Corromandel Aquafarm claims, "We have a pond full of shrimp, somehow untouched by the disease." Sample studies of the nearby waterbodies show that the virus has burnt itself out, says the Corromandal manager.

Nellore is not an isolated case. A recent neeri study carried out in 39 select farms in Tuticorin, Sirkali and Killai in Tamil Nadu, Nellore, Kakinada and Vishakhapatanam in Andhra Pradesh, and Palghar in Maharashtra on the west coast.

The study unequivocally blames extensive farming. NEERI's scientists have noted that while extensive and modified-extensive types of ponds rarely exchange water, semi-intensive ponds renew around 30 per cent of their water every day. neeri also studied the pond-bottom waters, with specific reference to suspended solids, biochemical oxygen demand (bod), ammonia and sulphides.

"Their concentrations are higher in the extensive ponds, followed by modified-extensive, and are the least in semi-intensive ones. This might be attributed to stagnation of water in the first 2 types." But waters that receive the twice-a-year megaload often go into "sudden shock".

There is a flip side to this "sudden shock" theory. The extensive system has low stocking densities and little supplementary feeding. Here, the fisheries department documents contradict the neeri report. Extensive farms are unlikely to play a significant role in increasing the organic load of the coastal ecosystems, the documents say, since both organic and inorganic inputs are comparatively lower.

In practice, many semi-intensive farms do not regularly recycle water, giving lie to neeri's report. Says B B Naik, senior environmental scientist of Deepsun Aquatic Farm, Aduan, Bhadrak, "We recycle the water every 15 days. Everything is all right."

NEERI has recommended the setting up of a series of aerobic and anaerobic sedimentation ponds and sand filters for effluent treatment. Profit-motivated industrialists, however, are likely to push for a simpler and cheaper design.

Overtaxed environment
Apart from "self-pollution", prawn cultivation has several other environmental fallouts, including the destruction of mangroves, increased salinity of surface and groundwater, effluents affecting coastal fisheries, and interference with fishing.

The latest hotspots of protest against mangroves destruction are the Kendrapara and Bhadgal districts in Orissa. Says Banka Behari Das of the Orissa Krishak Mahasangh, "The World Bank-assisted project in Kendrapara is located on forest land; and the Narendrapoor project in Bhadgal is inside the Bhitarkanika National Park." Similar complaints have cropped up from Tamil Nadu.

According to a document authored by Algarswamy, "Coastal mangroves are effective barriers against the tidal effect of cyclones." He maintains that destroying them would make the coasts more vulnerable.

Largescale pumping in of sea water as well as drawing in of ground water is common in aquaculture farm areas. Large intakes of groundwater lowers the water table, and sea water seeps into the aquifers. In village Pudukkuppam in Nagai-Quaid-e-Millat district, tests done by the chemistry department of the Gandhigram Rural Institute show that the salinity levels have crossed the tolerance limit of 350-500 milligrams per litre (mg/l). The water from the 1st pump had a salinity level of 2,200 mg/l, the 3rd 1,100 mg/l and well water from the village 1,650 mg/l.

NEERI's study recommended the setting up of a green buffer zone of over 250 m between prawn farms and residential areas and agriculture fields. The plan is to construct an earthen bund around prawn farms, with a drainage canal on the farm side to allow the seepage of pond effluent into the sea or estuary. The green belt is to be laid down at least 50 m away from shrimp farms with a bund on the inner side, and planted with 5-6 rows of casuarina trees to absorb saline water. But, warns the RDG, "Largescale aquaculture may bring in excessive demand on land resources, causing adverse ecological impact or resulting in multi-user conflicts."

In the fishing villages of Bhadrak, the elbow-to-elbow aquafarms force the villagers to take a 2-3 km detour to reach their homes. In Pudukkuppam, effluents from Sriram Marine Harvests Ltd flow down the Naithavasal irrigation canal. Village children play around in the shallow canal, which is lined with thick black sludge. Says Paramasivan, a local fisherperson, "We have to cross the canal to go to the next village, or when our boats land at a distant place. Some of us have got skin irritation."

There are widespread complains of a major chunk of estuarine shrimp seeds being bought exclusively by the industry. Says Arumukham of Pudukkuppam, "We don't get shrimps anymore as the aquaculturists pick them all up."

In Karaikkal, villagers have stalled the environmental clearance for Sriram Aqua Foods Ltd, which is setting up its aquafarm. They claim that apart from the 375 acres of fertile land, the site would corral in 30 acres of grazing land and 100 acres of casurina plantations. A spokesperson of DCM Sriram in New Delhi maintained, "We have won awards for environmental care. There would be no question of seepage of saline water because the ponds will be lined with clay. Moreover, instead of extracting groundwater, Sriram will bring water in tankers."

But in nearby Chinnorpettai village, the women are an angry lot. "We do not want saline water. We don't want anyone to steal our shrimp seeds. We don't want outsiders blocking our way." The village panchayat of Mandapattur village in Karaikkal has excommunicated people who sought employment with Sriram.

Loose control
Governmental control has been tardy. In Tamil Nadu, where 1,600 ha are already under aquaculture, fisheries minister D Jayakumar introduced a bill on March 14 prohibiting aquaculture in the wetlands, including mangroves, lakes, migratory bird routes, sanctuaries and in areas with scarce groundwater resources.

The bill recommended a 50-100 m buffer zone between aquaculture and non-aquaculture zones, and a gap of 20 m between each 500 m stretch of aquaculture farms. The state government has proposed a compensatory eco-restoration fund, in which each industrial unit would deposit Rs 5000 per ha. Similar moves are on the anvil in ap as well.

The rdg has called for "macro and microlevel surveys of the potential areas and zoning of the coastal area, using remote sensing data, ground-truth verification, geographic information system (GIS) and socioeconomic aspects." However, the guidelines have raked up a controversy by stating, "Traditional extensive methods consume the largest area of mangroves, with low productivity levels and as such this type of traditional culture should be discouraged as far as possible."

The guideline also advises against the use of chemicals piscicides and antibiotics in the hatchery and culture systems. "As far as possible organic manures and other plant produces should be used for such purposes."

The department recommends reduced farm stocking of shrimps (25 to 30 shrimps per sq m, less than 1/10th of the present industrial practice) to prevent disease outbreaks, and reduce the build-up of organic matter in pond bottoms. To prevent the depletion of wild seed stock, the department recommends only hatchery-produced seeds.

The environment management plan includes impact assessment of water sources in the vicinity of the farms, ground water quality, drinking water sources, agricultural activity, soil salinisation, waste water treatment and effects on the collection of wild shrimp seed.

A detailed plan for effluent treatment has also been suggested by the fisheries department. The guidelines note: "Waste water could be used for undertaking secondary aquaculture products, particularly for culture of mussels, oysters, seaweed, other finfishes, etc." This would not only enhance the income of the acquafarmers, but also would help upgrade water quality by filtering out organic material.

In short, the guidelines are idealistic, but for some confusion about the relative merits of traditional and semi-intensive cultures. The state governments and the industry are yet to respond to these guidelines.

Here, then, is a booming industry with huge collateral damage. In such economic hyperactivity, clashes between interest groups may be inevitable. But India has potentially powerful rules and regulations which could help strike a balance -- if it can net in every party concerned.