Energy Cost in Carp Farming Systems

Central Institute of Freshwater Aquaculture (CIFA)
Dhauli, Kausalyagang, Bhubaneshwar

NETWORK OF AQUACULTURE CENTRES IN ASIA
BANGKOK, THAILAND

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ENERGY COST IN CARP FARMING SYSTEMS

J. Olah* and V.R.P. Sinha

Freshwater Aquaculture Research and
Training Centre
(CIFRI)

P.O. Kausalyagang
Via Bhubaneshwar 751 002
Orissa (India)

* Fisheries Research Institute
H-5541 Szarvas
P.O. Box 47, HUNGARY

Introduction

Increasing attention is being paid to initiate research and analysis on the energy cost in different food production technologies ranging from agriculture to livestock farming to aquaculture. Since aquaculture embraces different systems of farming of fish and shell fish in a variety of enclosures and also with different management measures it is essential to assess and compare energy budget of these farming systems. At times, the production rate is quite high in certain systems and quite low in others and in terms of monetary input output particular system may appear quite economically viable, yet when energy input/output is calculated, it may show a poor output. In fact, many high yielding technologies may show promising monetary economics but looking at the energy economics it may show a different picture. Further, on the basis of monetary economics, input/output ratio in different production systems cannot be easily compared globally whereas energy economics provides a uniform basis of input/output comparison of such farming systems in different parts of the world. Therefore, industrial energetics, budgeting the energy which may be required to carry out the various stages of a food product has been analysed. Biological energetics, describing the flow-pathways and efficiencies with which solar radiation is converted to produce food in an ecosystem by the plants and animals and fish is not under the purview of the paper since it is difficult to calculate the whole of biological energetics which is dependent on the different fish species/sex/age, their metabolism and the food chain and their interaction with the ecosystem. However, the final biological product as fish is taken into consideration to calculate the input/output ratio.

Of all the aquaculture systems, carp culture in ponds has the longest history and is thus widely undertaken in different countries of the world. There are two major systems of carp culture i.e. polyculture of different carp species and monoculture of common carp. The empirical knowledge gained over several centuries from traditional pond culture has largely provided the basis for scientific fish culture involving proper preparation and fertilization of pond and supplying supplementary feed to the fish. However, due to shortage of inorganic fertilizers and increasing availability of millions of liters of sewage with growing population, the use of the latter in fish culture has assumed great importance and is yielding encouraging resulting (Sinha, 1976). The integrated carp farming with livestock and agricultural crops is being extensively tried in different countries in recent years with excellent results. Further, carp farming in cage and closed warm water recirculation system has also been developed recently in several countries. Thus, carp farming in these different systems has been chosen for energy cost analysis mostly with the data collected in India and in Hungary.

Energy budgeting

Standard conversion factors were used to get the energy cost of construction and operation items including feed and inorganic fertilizers, as have been explained in Table 1. Table II shows the analysis of the amortization of the energy cost required for construction of fish pond, cages and closed recirculating system under Hungarian conditions. The total energy cost on each item was divided by the amortization time in years, assuming life span of each of the item as 20 years, and by the tonnage of fish produced in the culture unit to get the yearly amortization shared to 1 tonne of fish yield. The man-power energy required for construction and running the production unit has not been taken into the industrial energy budget due to ethical consideration. The energy cost for stocking material was calculated for each management level as if the fingerlings were cultured with the same management method.

Farming of carps in Indian pond

In India through polyculture of carps, over 10 tonnes/ha/year has been produced at different fish farms and over 7 tonnes/ha/year has also been produced by the farmers by fertilizing the rural ponds and supplying the feeds to the fish. For the present analysis, actual production obtained at Jaunpur, Uttar Pradesh has been considered where the energy cost on construction has been kept as nil since these ponds in the farms have been in existence over 20 years. When production cost in terms of industrial energy is calculated in different management methods, it appears that the best input/output relation is obtained when the pond had no fertilizer application nor the fishes were given supplementary feeding. However, the production rate was much less than with feed and fertilizer. Similarly, in undrainable ponds, production 3.5 tonnes/ha/year has been taken for analysis, since this production rate can be easily obtained by a fish farmer with minimum of feed and fertilizer. As it is obvious from the table III, the input/output ratio appears quite promising. The production systems involving different management process appear quite energy effective since they are based primarily upon the considerable year round natural production accelerated by fertilization and with minimal amount of supplementary feeds in the form of rice bran and oil cake. At times, in perennial rural ponds, even the fertilization itself is supplementary to the high organic load normally existing in these old ponds because of multi-purpose use of the pond water.

Farming of carps in Hungary in different enclosure

As is obvious from table II, the amortization of energy cost for construction of fish pond is the minimum compared to cage and closed recycling system. In pond construction items, moving soil for excavation and embankment construction requires nearly the same quantity of energy as that of the concreting inlet and outlet structures. The machinery appears to be third important item in the energy expenditure. Most of the energy cost in cage culture is needed for aluminium and plastic and used for the holder unit and for the net whereas in the recirculating system the energy cost is distributed nearly equally in concrete, steel and pleastic.

Table IV, shows the details of energy cost with different management levels in carp farming in Hungary. The pond with polyculture of carps and with organic manuring shows better input/output ratio compared to inorganically fertilized ponds or when fertilizer was applied to the pond and also feed mainly cereals were supplied to the fish. Though inorganic fertilization is most prevalent in European countries, the recent trend is to utilize organic manures. Daily domestic sewage introduction 150 m³ ha^-1 and in case of pig manure 5 m³ ha^-1 would result in very high production ranging from 3 to 10 t ha^-1 yr^-1 in Hungary and in India respectively, while the fish is produced under this system the sewage also gets purified. To purify 1 m³ sewage in a regular purification plant 720 to 947 KJ energy is required (Table V). The above energy is required (Table V). The above energy cost include aeration and pumping and other operational energy. The energy cost for initial construction of the plant, which is quite high was not included into the energy cost analysis. The energy cost of the purification of the quantity of sewage to produce 1 tonne of fish in regular sewage purification plant is between 5.4 and 7.1 GJ i.e. every tonne of fish produced with the liquid organic wasted would save this amount of energy. Thus, the total energy input in the fish production process minus the energy required for purification of sewage comes to 96 KJ to got 1 g unprocessed protein in the sewage fed or manured ponds.

When inorganic fertilizer is used in the farming system and no supplementary feed is provided the production capacity is around 2 t ha^-1 in 150 growing days in Hungary which is lower than the production obtained in the ponds with organic manuring. Yet, in this system there is a marked increase in the energy cost of all the items making -he total energy input much higher (Table IV). Still the system appears to be energy effective and the energy input and output ratio appears quite good. While the energy input per energy output is 10.6, the KJ input/gram protein is 275. Similarly, when cheap cereals are given to the fish the production increases but the KJ input per 1 g protein also increases to 418.

Increasing the management level further in such pond farming system, using complete pelleted diet of very high protein level and stocking the ponds heavily and aerating the water to dispose off the metabolic byproducts, requires high energy intensive approach. The aerated fish ponds show the production level at the rate of 6 t ha^-1 during 150 days. The total energy input per ton of fish in this system comes to 86.8 GJ and the energy input per energy output is 18 and the KJ input, gram protein is 468 (Table VI).

Table VI shows the energy cost analysis on a model cage culture farm developed in Hungary. The data were collected from 5 farms. During the growing season of about 150 days in Hungary, a net yield of 1 ton of fish produced in 50 m³ water. Nevertheless, the construction of cages, feed and operation energy cost also increases. The energy input to output as well as the KJ input per gram of protein output become high and come to about 23 and 622 respectively (Table VI).

Several recirculating water systems are functioning in Europe and in North America for rearing both salmonids and cyprinid species. One of the largest units for warm water fish species was constructed at the Fisheries Research Institute in Hungary for research experimentation. Due to the very high maintenance and running expenses, the closed heated system is used also for commercial fingerling production of high valued fish species like sheatfish, pike and sturgeon. Under this system about 1 tonne of fish is produced in 18 m³ in 150 days. The analysis of energy cost shows clearly that this system is highly energy input oriented (Table VI). An energy quantity of 7.6 tonne oil is required to produce 1 tonne fish.

Table I Energy cost of fish culture technologies in pond in Hungary. GJ requirement for producing 1 tonne fish

Table II Amortization of energy cost required for constructing the different fish rearing facilities under Hungarian Condition. GJ amortized for producing 1 tonne fish

Gigajoule = 10⁹ joule

Table III Energy cost of fish culture technology with increasing management level in India. GJ requirement for producing 1 tonne fish in shallow and undrainable ponds

Table IV Energy cost of fish culture technologies in pond in Hungary. GJ requirement for producing 1 tonne fish

Table V Energy cost of sewage water purification. KJ required to purify 1 m³ sewage

Table VI Energy cost of fish culture technologies under Hungarian condition requiring energy intensive, high protein pelleted food. GJ requirement for producing 1 tonne fish

Discussion

A comparison of industrial energy for carp farming systems and of livestock farmings is shown in Table VII. It is obvious that in almost all carp farming system, except that of recirculating system, energy input is less compared to other livestock farming systems. Even the poultry egg production which is the most energy effective, requires about 552 KJ for 1 g of protein. However, among the different technologies of carp farming systems, farming in ponds without supplementary feed and fertilizer and in sewage-fed ponds appear to be the best systems requiring the lowest amount of energy. This is mainly because the amortization of energy cost required for construction of ponds is quite low compared to cage or recirculating systems (Table II). The amortization for producing 1 tonne fish in pond farming required about 0.1 tonne of oil whereas in the closed and heated recirculating system, it is nearly equivalent to 1 tonne of oil. For cage culture the value comes around 0.5 tonne of oil. Also the energy cost for operation is less except the manpower which is not included in this analysis. However, the energy cost of the stocking material is the single significant item in the energy expenditure and the energy input per energy output is less than 1.

This means that more energy is stored in the harvested fish flesh than was consumed during all the production processes. The KJ input per gram protein output is around 22. Thus, this is a unique production technology in the animal husbandry and yet it is mostly unexplored since many small or middle sized perennial ponds or lakes are available all over the world still unutilized for proper fish culture. Most of them are productive or even hypertrophic and are functioning in a very imbalanced state because of the organic overloading. In the European part of the Soviet Union, many ponds and small lakes were converted to semiintensive fish culture unit during the last decade. The same trend needs to be developed in India where a large number of small rural perennial ponds very rich in nutrients needs urgent culture intensification.

The next best system appears to be sewage-fed ponds which needs worldwide serious attention considering the energy involved is sewage purification and sewage contribution to fish production. Further, partial or complete replacement of inorganic fertilization by organic manuring preferably keeping livestock, duck-cumpig near the pond would economise the industrial energy cost. Also serious search is needed for cheaper locally available feed for those farming systems which involve use of supplementary feeding. Thus, considering all these it appears that global attention needs to be paid and high priority assigned for proper pond nutrient recycling and organic waste recycling through carp farming in order to make these systems of aquaculture still more energy effective for protein production.