Analysis of the data collected during the year in review leads to the following conclusions:

• Coastal waters off Porbandar (Gujarat) showed high levels of BOD and nitrite which is mainly due to discharge of untreated domestic sewage into the coastal waters. Further studies on biomass
• production and species diversity of sea weeds along Porbandar coast revealed that the species of Sargassum, Turbinaria and Gelidiella have become extinct possibly due to discharge of effluents from chloro-alkali industry. The sea off Okha did not show any significant levels of pollutants.
• During the previous year the level of dissolved oxygen in the Mahim, Thane creeks (Maharashtra) was almost nil during the low tide period. However, an improvement in the oxygen values during low tide were observed during the year 1992. The data collected on toxic heavy metals like cadmium and mercury revealed that their levels were high as in the previous year. Benthic population in these areas continued to remain very low, indicating that the pollution in the bottom layer, particularly in the sediments remains a matter of concern. However, the coastal waters off Ratnagiri showed no significant levels of pollutants.
• The coastal waters off Mangalore (Karnataka) contained low level of oxygen due to discharge of untreated domestic sewage. The data on other parameters did not reveal any serious pollution in this area.
• In the sea off Cannur (Kerala), high values of dissolved petroleum hydrocarbon was observed due to intensive operation of fishing crafts in that area. The coastal waters off Kozhikode are affected due to fishing activity, timber industry and rayon factory which discharge effluents into the Chaliyar river. Although deterioration of water quality was noticed at times, there was no evidence of severe impact of discharge of effluents. The high levels of mercury and petroleum hydrocarbon decreased towards the offshore areas. Higher concentrations of ammonia, phosphates, nitrite and nitrate were observed in the estuarine regions. However, because of dilution by tidal action and biological uptake the low levels could not be observed in the coastal waters off Kochi. The nearshore waters at Veli near Thiruvananthapuram, were found to have high acidity levels, due to discharge of effluents from a Titanium factory. The pH at discharge point was very low. Bacterial analysis of water and sediment samples collected along the Kerala coast revealed that sediment samples were more contaminated, particularly in stations Vizhinjam and Kozhikode, mainly due to discharge of untreated domestic wastes into the coastal waters. Analysis of heavy metals in water samples revealed that mercury was present in significant amounts at Kozhikode and Veli. High concentration of copper was also observed in waters off Kozhikode, Kochi and Kollam.
• The sea water off Tuticorin (Tamil Nadu) contained significant levels of mercury and pathogenic bacteria due to discharge of untreated domestic wastes and industrial effluents. Low level of dissolved oxygen was evident off Ennore estuary and off Cooum river which carry industrial and domestic wastes into the sea.
• The pollution monitoring studies along the coast of Andhra Pradesh during earlier phase revealed low levels of oxygen and increased levels of ammonia, total phosphorus, nitrogen and suspended matter at Gautami-Godavari, Kakinada Bay and Kalingapatnam transects showing the impact of riverine runoff and sewage from neighbouring areas through Godavari and Vamsadhara rivers. In Kakinada Bay high BOD values ranging from 2 to 4 mg/ltr. were observed. The results of studies conducted recently revealed that the pollution levels at Kakinada Bay remain unabated. Visakhapatnam Harbour receives wastes from domestic and industrial units, located around it. The Harbour wastes reach the coastal waters. Low values of DO and high values of phosphate, ammonia and metals were noticed in the Visakhapatnam Harbour.
• The oxygen values at Gopalpur (Orissa) transect exhibited relatively lower values indicating the impact of discharge of untreated, domestic sewage. The sediment samples also showed high concentrations of lead and mercury.
• The impact of discharge of wastes was evident from the high values of pathogenic bacteria at Sandheads (West Bengal). The decreasing oxygen levels at the mouth of the river Matla due to discharge of untreated municipal wastes of Calcutta Municipal Corporation and adjoining areas has been a matter of growing concern.

The results obtained on sea water quality parameters along the coastline revealed that the pollution problems are localised and mostly occur in the sea off metropolitan cities and thickly populated coastal towns. However, because of dilution by sea water the levels of pollutants have not reached alarming stage. There is a linear decrease of pollutant levels towards the offshore, e.g. the sea off Bombay.

A study of sources of pollution along the coastal waters revealed that direct discharge of domestic and industrial wastes are confined to few places like Bombay, Madras, Visakhapatnam, Porbandar, Veli near Thiruvananthapuram, Tuticorin, Kakinada etc. Pollution is caused from inland sources and to a certain extent from the banks of estuaries. When the discharges reach coastal waters, there is a dilution due to interaction of salt and sea water and lack of flushing in certain areas, and the pollutants settle down and get absorbed and accumulated in sediments. This is clearly evident in Kochi backwaters, Ennore estuary etc. Such areas are likely to become highly polluted areas (hot spots) in due course, severely affecting the benthic fauna and other bottom feeding organisms, Due to interaction between the sediment and bottom layer, the pollutants gradually find their way into the sea and contaminate the seawater and marine life. In order to constantly monitor the pollution levels around and beyond the discharge points (both domestic and industrial) and also to study the impact of discharge of domestic sewage into the estuarine waters which ultimately affect the sea water quality in the nearshore areas, a comprehensive programme on intensive monitoring of Hot Spots is being launched. Forty such Hot Spots have already been identified in consultation with the concerned State Pollution Control Boards. These are:

The data collected under the COMAPS programme have been found to be useful in monitoring the levels of pollutants along the coastal waters. Whenever abnormal values have been found the same have been brought to the notice of the concerned State Pollution Control Boards for remedial measures.

A Danish tanker 'Maersk' carrying 300,000 tonnes of light crude oil collided on 23 January 1993 with an empty Japanese tanker 'Sanko Honour' outside India's Exclusive Economic Zone (EEZ) about 110 km south-east of the Indira Point off Greater Nicobar Islands, resulting in the leakage of oil into the sea. Due to the prevailing wind the tanker drifted 56 nautical miles in west and north-west directions causing pollution of the marine environment. A fire also broke out on the tanker which continued upto 26 January when it was put out by the salvagers. As the collision of vessels and the resultant oil spill posed a threat to marine environment in the vicinity of the Nicobar Islands the Coast Guards organisation after finding out the location of collision, commissioned the Coast Guard vessel at Port Blair for combating operations. Another vessel 'Vikram ' equipped with booms, skimmers and chemical dispersants was also pressed into service. The combating operations consisted of spraying chemical dispersants first from an aircraft and later from the two vessels to emulsify the oil to facilitate breaking of oil layer and its faster bio-degradation. A salvage company from Singapore succeeded in blocking the leakage of oil on 2 February 1993 and the vessel was later towed beyond India's EEZ. The owners of the tanker arranged for transfer of remaining oil from the ill fated tanker to another vessel. The environmental consequences of this maritime casualty as well as measures for containment of damage to environment and ecology of Nicobar Islands and possible legal measures against the owners of the vessel etc. were reviewed by the Inter-Ministerial Coordination Group. The Oceanographic Research Vessel 'Sagar Kanya' was sent to the site with 12 scientists for collecting samples of water and marine life in the affected area. On the basis of the . investigations a preliminary assessment of the damage caused to the marine environment is expected to be completed. The long-term effects of the spill on the benthic life would also be investigated by scientists and if necessary, another research cruise will be undertaken.

The Experimental Wave Power Plant at Vizhinjam Harbour (Kerala) which successfully demonstrated generation of electricity from wave action, has been declared as a national facility for Wave Energy and other Wave Application Studies. The test facility is for differential design of turbine, testing of metals against sea corrosion, orientation of sea water structures, etc.

With the experience gained on the construction of Experimental Wave Power Plant at Vizhinjam, the Department has taken up two new projects relating to construction of breakwater integrated wave energy systems at Thangassery in Kerala and Mus Point in Car Nicobar. These plants will have an installed capacity of 1 to 1.5 Mw. The Department of Agriculture & Co-operation and the Ministry of Surface Transport who have been proposing to construct breakwaters at Thangassery and Mus Point, are involved, in addition to the Ocean Engineering Centre of lIT, Madras, in the execution of these projects. An expert group to work out the technical and financial aspects of the project at Mus Point has been constituted by the Planning Commission. Detailed designs for civil, mechanical and electrical works have been taken up. Necessary model studies for designing the breakwater integrated wave energy systems are being undertaken at lIT, Madras. The completed design for Thangassery Harbour is expected to be available by June, 1994 and that of Mus Point in June, 1995.

5.5 Island Development Programme

The following projects have been implemented in Andaman & Nicobar Islands:

(1) R&D-cum-Demonstration Centre for Prawn Culture

(2) Demonstration of Polyculture of fish in floating cages

The project on Prawn Culture is being implemented in 10 hectares of land acquired at Dolleygunj near Port Blair in Andamans. During the first phase of the project, 2.4 hectares of land was developed for construction of two ponds each of 1.2 hectares. The ponds were designed on a scientific basis, the acidic soil treated with lime to enhance its pH and prawn seeds obtained from mainland stocked and fed with indigenously developed feed. Three electrically operated aerators were used to oxygenate the pond water filled with sea water from adjoining Bay.

Extensive method of culture has been adopted at present for these two ponds with a production target of 2.5 tons/ha/year to be achieved in three stages. However, during the first crop initiated in August-September, 1992, and harvested in January, 1993, a production target of 1.25 tons/ha/ crop has been achieved, which is above the level of the target set for the first crop itself. During subsequent crops the techniques adopted will be standardised. Demonstration of culture methods to the local farmers have already commenced in the Islands.

During the next phase, the entire 10 hectares is proposed to be used for demonstrating extensive and semi-intensive methods of culture. The targeted production under the semi-intensive method will be around 3 to 4 tons/ha/crop.

The SELMAM programme envisages precise measurements of Mean Sea Level (MSL) variations due to global climatic change etc. and assessment of the impact of such variations on the coastal belts of India. The programme has 3 basic components namely, (i) establishment of accurately measuring tide gauges (ii) preparation of microlevel coastal area maps and (iii) development of predictive models. It is proposed to set up 11 modern tide gauge stations at Bombay, Veraval, Goa, Kochi, Tuticorin, Madras, Machilipatnam, Vishakhapatnam, Paradeep, Calcutta and Kavaratti. The tide gauge' station at Goa will be the national reference station. In addition, microlevel coastal area maps of the stretch between Nellore to Machalipatnam will be made in I :25000 scale. The data from these studies will be used to develop predictive models.

A second generation of the Pressure Sensor Tide gauge (PST) which has a reading accuracy of about I mm has been fabricated.

A prototype of the digital tide gauge based on optical shaft encoder has also been developed. This will replace the traditional float type tide gauges of the Survey of India.

The national reference station at Goa is nearing completion.

5.7 Coastal Ocean Design & Prediction System (CODAPS)

Three CODAPS Cells, each at Indian Institute of Technology (lIT), Madras; Andhra University, Visakhapatnam; and Jadavpur University, Calcutta, were established in 1991-92.

The objective of this programme is to:

-design, develop and operationalise data-assimilative predictive ocean system models;

-improve ocean related equipment & instrumentation, engineering and management systems;

-stimulate R&D; and

-provide extension training and consultancy services.

The work undertaken at IIT, Madras, under this programme includes user-oriented problems such as coastal erosion and accretion; development of user-friendly softwares; R&D studies on wave energy and operationalisation of the storm surge model developed by IIT, Delhi; development of numerical models for prediction of nearshore phenomena; and creek hydrology of Kondaleru estuary (Andhra Pradesh). Under the project on Site Specific Design on Wave Energy, model testing of integrated wave energy system for Thangassery Fishing Harbour and designing of new turbine system for Thangassery project have been undertaken. Initial work was done on development of user-friendly software under the project on Development of Numerical Models. Detailed geographical information about creeks has been collected under the project on Creek Hydrology and the problem is being investigated through computer model. The Storm Surge project has been geared up to predict storm surges during the cyclonic weather. The surges occurring during the rough weather are predicted and found to agree with the observation values to the level of 95%.

The objective of this Cell is to promote biological oriented activities particularly to deal with the impact of human activities and disasters in mangrove ecosystems, prediction of abundance of fish along the Andhra Pradesh coast and organisation of training programmes on ecology and environment of marine ecosystems.

Two R&D projects have been taken up at this Centre.

The project envisages forecasting of sardine fish along the north Andhra coast on short term basis. The past data required on fisheries and oceanography in this region are being collected from the National Institute of Oceanography, Goa; Central Marine Fisheries Research Institute, Kochi; and Fishery Survey of India, Bombay. Additional data are to be collected for a period of two years and the forecast model would become available in, the third year of the project, i.e. 1995-96.

Detritus is an important component of mangrove ecosystem. Nearly 80% of the fish feed on detritus. Disturbances caused on account of deforestation, use of mangrove land for brackishwater aquaculture, etc., cause imbalance in the detritus-based food chain of mangroves. In order to study such impacts and evolve conservation measures, it is proposed to develop a mathematical model on the impact of human activities in the mangroves.

The project has commenced recently and detailed survey of Gautami-Godavari mangrove ecosystem has been made and sites for investigations identified. Methodology for undertaking such work is being standardised and experimental activities on decay of mangrove leaves to form detritus are in progress.

The CODAPS Cell at Jadavpur concentrates on oceanographic and coastal problems, particularly on coastal erosion of West Bengal and is responsible for operationalising the storm surge model for West Bengal and Orissa coasts. The following projects were taken up during 1992-93:

Under IGBP the Department is coordinating the activities at national level the Joint Global Ocean Flux Studies OGOFS) initiated by the lnter Governmental Oceanographic Commission. A national JGOFS committee was constituted in August 1991 to identify and guide the Indian component of JGOFS. The national JGOFS aim to study the flux of carbon in the Arabian Sea as part of the international investigations on the carbon budget of the world oceans. A few projects have been identified for this purpose. The work on the creation of infrastructure required for the investigations has been taken up. Detailed cruise programmes of research vessels are also under preparation.