Living fresh-water and marine resources can provide large quantities of high quality proteins. Aquatic habitats are much more extensive than land surface.
A large area of earth’s surface is covered with water and there are big in-land fresh or brackish water bodies as well as rivers which can be utilized for the cultivation of additional resources to the mankind. In a number of countries proteins obtained from aquatic sources constitute a major portion of total per capita protein intake. For example nearly 25% of dietary protein requirement of average Japanese is met with by fishes and other products from aquatic systems.
The world catch of fishes and other products from marine and fresh waters grew at the rate of about 6% per year between 1950 to 1970. This growth nearly tripled the world production within a span of two decades. Following 1970 A.D., there has been a steady rise at a somewhat slower pace.
Fishes make up about 88.6%, lobsters, crabs, shrimps and prawns account for 3.2% while clams, mussels, oysters, squids and octopus etc make up about 6.3% of the total weight of harvest from aquatic systems. Edible and industrially important algae represent about 1.9% of this harvest.
Global production of fish and other edible material from aquatic systems has suffered serious setbacks following 1970 A.D. The oil crisis of 1973 and then 1978 caused many large vessels to stop fishing activity. Rising pollution of fresh water, bays, estuaries and coasts has drastically reduced fish populations. Deep-sea fishing activity was also adversely affected because of the diminishing fish-stock as most of the fishes have to return to the coastal region for spawning and breeding where pollution affected the process adversely. However, growth of aquaculture which involves rearing and husbandry of fishes and other animals under human care has raised the harvest from aquatic systems substantially.
Fishes and other animals can be captured from water or they can be reared and domesticated in small or large enclosures to be captured and used whenever required. Global fishery resources, therefore, may be discussed under the following two headings:
1. Capture fisheries.
(2) Capture Fisheries:
Man has been harvesting fishes and other edible products from aquatic systems since time immemorial. Capture fishing is a practice as old as civilization itself or even older. It takes advantage of the natural productivity of aquatic systems. Availability of plant nutrients, like phosphates and nitrates, in natural waters, stimulate plant growth-mainly algae-which supports a large variety of aquatic organisms like fishes, crabs, lobsters, shrimp, clams, oysters, mussels, squids, etc. which are useful to the mankind. Both fresh and marine waters are harvested for obtaining these products:
(A) Capture Fisheres in Fresh Water:
Earth’s surface possesses a large number of depressions in which rain water collects to form lakes, ponds or reservoirs In addition there are innumerable channels, streams and rivers which possess a regular all the year round flow of water. The total amount of fresh-water present in lakes and reservoirs is about 280,000 cubic kms, while water which is available in streams and rivers at any point of time amounts to about 1200 cubic kms.
These provide an excellent habitat for aquatic life to develop. However, collectively, fresh-water systems represent a very small fraction, less than 0.02% of the total amount of water present on our planet. That is why the total contribution of fresh-waters to global harvest is about 10-12% only (Fig. 5.2).
Nutrients are generally not scarce in fresh water systems but the productivity is often affected by pollution of aquatic environment. Discharge of sewage effluents in fresh water systems creates unhealthy conditions which result in disappearance of desirable fishes and other organisms and abundance of undesirable ones.
(B) Capture Fisheries in Marine Waters:
The bulk of fish and other products from aquatic systems come from marine habitats (nearly 85 to 90%). Our oceans contain more than 97% of the total water free for circulation on this planet, covering an area of 361 million sq. kms. Total annual productivity of our oceans has been estimated to be about 55 billion metric tons in terms of dry biomass. Oceans provide an excellent habitat for aquatic organisms to grow. Fishing activity in marine environment can be grouped into:
(a) Coastal Fishing:
Fishing activity near the shore-line which can be carried on by small boats and vessels, comes in this category. The zone of shallow waters near the coast is usually highly productive region as plenty of nutrients are present being derived from the bottom underneath as well as from surface runoffs from land. Good plant life develops in this zone which supports a rich crop of fish and other animals.
However, the productivity in coastal zones may at times be limited by pollution of the aquatic environment caused by discharge of wastes and waste-waters. In a number of developing countries where fishing activity is largely carried by small fisherman, the coastal catch constitutes a major part of the marine harvest.
(b) Deep Sea Fishing:
A large part of the total annual catch of fishes and other marine products comes from fishing in deep waters which are approachable only by large boats or ships. In developed countries where fishing is an organized industry, large boats and vessels are used for the purpose. Due to heavy cost involved deep sea fishing activity is limited and contributes little to the overall harvest from marine environments. The deeper zones of sea are relatively free from the effect of pollution which is an important factor in coastal fisheries.
However, as many fishes migrate to coastal region for breeding purposes the overall population may be affected by adverse conditions in the shallow waters near the shore. Unlike coastal regions, the primary production or the biomass of green plants may be affected adversely due to nutrient limitation in deeper waters.
This naturally affects the fish biomass. According to one estimate we were already harvesting nearly 70% of the total available stock of fishes and other animals by 1972 A.D. We have to leave out some fishes in their natural habitat so that there could be a good crop for the next harvest. Over-harvesting or putting too much strain on the system could damage it for a considerable period of time.
The population of fish and other animals in aquatic environment has often been considered to be an open resource – the fish is said to belong to those who capture them. However, due to the enormous increase in the size of catch during the past 40 years or so, it was realized that the biological resources of ocean are also limited and can be affected by unrestricted fishing.
This has lead to the enclosure or demarcation of zones in the oceans in which fishing activity can be carried out by a country. An agreement allocating the living resources of the area within 200 nautical miles of the coast-line to the country concerned has been ratified by most of the maritime countries. This zone is referred to as the Exclusive Economic Zone or EEZ of the country concerned. Waters beyond this zone are open to anyone wishing to use them.
Aqua-culture involves farming and husbandry of fresh-water and marine organisms. In many parts of the world aqua-culture and mari-culture (cultivation of marine organisms) are very ancient occupations. However, the worldwide potential of aqua-culture as a source of food and other industrial products has only recently been recognized.
Aqua-culture is a labour-intensive occupation. It is most suitable for densely populated, poor countries of the world where labour is cheap and per capita income is low. Unlike capture fishing wherein the size of the catch is determined by the magnitude and availability of populations, aqua- culture is limited only by the size of the suitable area. The natural productivity of the waters concerned is of little importance in aqua-culture as food for the developing populations can be provided from outside sources.
A major portion of the global produce from aqua-culture comes from under-developed countries where the labour is cheap. There has been rapid growth in aqua-culture which has transformed itself into a full-fledge industry now. From a meager about 1-3 million metric tons per year in early fifties the total global production has now jumped to about 18 million tons. In a number of developing countries it provides the much needed high quality proteins, foreign exchange and employment to millions of people. Together with agriculture, aqua-culture may also provide a desirable way to make use of animal and human wastes.
India has an old and traditional fishing industry. Both capture fisheries and aqua-culture were practiced in India in ancient times. In parts of Bihar, Assam, West Bengal and Orissa, possession of a pond or a tank has been considered as a sign of prosperity. Ponds attached with individual households provided water as well as fishes for the domestic needs. In a large part of our country, traditional fisheries and aqua-culture continues even today. Modern techniques of capture fisheries and aqua-culture have, however, influenced a small part of our fishing industry only.
We have a huge fresh-water and marine fisheries potential but only a small part of it has so far been tapped. The growth of Indian fisheries has been pretty slow following independence till 1985, in which year a total harvest of about 2.72 million tons was obtained. A steady growth rate of about 6.25 % per year, however, resulted into a harvest of about 3.84 million tons in 1991 A.D. while in the year 1994 a total production of 4.5 million tons was recorded.
1. Inland Fisheries in India:
In India inland fisheries play a very important role as compared to other countries of the world. About 40% of the total harvest comes from inland fisheries, the bulk of which comprises of fresh water fishes which inhabit ponds, tanks, rivers, and reservoirs spread over about 5.5 million hectares in India.
The total production from fresh water in 1991 A.D. was about 1.54 million tons which rose to 1.85 million tons only by 1994 A.D. It has been estimated that Indian waters can produce about 5 million tons of fresh water fishes. We are utilizing only a small part, about 35-40% of this huge potential. This is because of the fact that Indian inland fisheries suffer from a number of disadvantages which are as follows:
1. Pollution of inland water bodies.
2. Lack of scientific management.
3. Lack of necessary means of fish farming.
These are not such problems which cannot be solved by careful management. Many state Governments are doing excellent jobs in this direction in India. In addition to their efforts, there is also a pressing need for diversification. In fact the entire basis of fish production in fresh-waters is about half a dozen species among which carps predominate. A large amount of total catch of fishes has a little market value.
There is no basis for such discrimination except for a little variation in taste and flavors. These fishes are equally nutritious as carps are. The average productivity of these fishes is much higher than those species which are considered desirable ones. We can further enlarge our fresh water fisheries by careful storage and management of the enormous quantities of water which flows directly to the sea unused.
2. Marine Fisheries in India:
India has a coastline of about 6,000 kms. India’s Exclusive Economic Zone comprises of about 2 million sq. kms which possesses excessively rich population of fish and other useful animals. The total potential of marine fisheries in India has been estimated to be 3.9 million tons per year. Out of 4.5 million tons of total fisheries production in the year 1994, the share of marine fisheries was about 2.3 million tons only.
India has also not progressed much in coastal aqua-culture or sea farming. Shrimp farming is the only activity which has gained momentum rather recently. The area under shrimp farming is about 70,000 hectares which produces about 47,000 tons of shrimp – largely exported to other countries.
We have yet to launch cultivation of mollusks, fin-fishes such as sea-bass, sea-bream, snappers, groupers, etc. Sea bed cultures of oysters, clams, mussels, scallops and gastropods which are farmed in rafts and trays are yet to make a beginning in India. Sea-weeds culture for which there is an enormous scope has not even started.
The poor performance of marine fisheries and coastal aqua-culture is due to a number of problems which can be summed up briefly as follows:
1. In India capture fisheries are largely carried out by small farmers who have meagre resources. Their activity is largely restricted to coastal regions nearby – deeper waters are beyond their reach. This leaves a large part of Indian EEZ untouched.
2. Pollution of coastal waters, land-locked bays and estuaries tends to reduce the fish stock greatly.
3. Aqua-culture is largely hampered by lack of resources and technical know-how. For aqua-culture we require large amounts of fish seeds and germlings. For example, shrimp farming has been in trouble because of non-availability of shrimp seeds.
(5) Improving the State of Indian Fisheries:
The fish stock and the stock of other useful animals from our aquatic systems reflect the natural productivity of our water bodies. It is a renewable resource which, however, does not accumulate. The size of populations is determined by the primary productivity of the natural systems. If we do not use the potential fully the left over stock is recycled within the system and is wasted.
Regular harvesting regenerates it. Both inland and coastal waters have already reached a point from which much cannot be expected. Deep sea fishing is in a very primitive state in India and about 90% or more of this vast potential lies untapped. Organized efforts should be made to develop a fleet of large boats, trawlers, ships etc. to harvest sea food from deeper waters.
Another important aspect which deserves attention here is the reduction in magnitude of pollution of our water bodies. In fresh waters, land-locked bays, estuaries and coastal regions the discharge of waste waters causes much damage to fisheries.
Desirable species which cannot tolerate the adverse conditions disappear. Wherever possible this discharge should be stopped or else, diverted to treatment plants so that the waste-waters may not be too injurious to the aquatic systems when discharged finally.
The potential of capture fisheries which depends largely on the natural productivity of aquatic system being limited the future shall probably witness a rapid rise in aqua-culture. The farming of fishes and other economically useful animals utilizes natural productivity as well as the energy source provided from outside. Presence of suitable waters, space or location is the only requirement of aqua-culture, which is a labour-intensive industry. We have plenty of suitable waters, space and labour to carry out the farming.
All we need is the technical know-how, the technology for growing different kind of sea food in India. We have been successful in shrimp farming from which we earn an exchange worth Rs. 3270 crores annually. We should expand our aqua-culture to cover other economically useful organisms and cash in the lucrative international market of sea-food which occurs around us.