III/R-1
ECONOMIC ASPECTS OF FISH FEEDING IN THE NEAR EAST

by

S. TAL
Fisheries Division, Ministry of Agriculture
Tel-Aviv, Israel

and

B. HEPHER
Fish Culture Research Station
Dor, Israel

Abstract

Feeding of fish on a commercial fish farm is economically feasible only when the farm is over about 20 ha in area. Because of high investments, fish culture is economic only if high fish yields can be obtained by the addition of feed. The cost of production per ton of fed fish is much lower than that of unfed fish.

A balanced diet formulated with due consideration of the natural food in the ponds may bring good returns in carp yield. If it gives good results it should be economically analysed, and the “break-even” price of the feed be ascertained, before its commercial use.

ASPECTS ECONOMIQUES DE L'ALIMENTATION DES POISSONS EN MOYEN-ORIENT

Résumé

L'alimentation du poisson dans un établissement piscicole commercial ne présente un intérêt économique que lorsque l'exploitation a une superficie supérieure à une vingtaine d'hectares. En raison de l'importance des investissements nécessaires, la pisciculture n'est rentable que s'il est possible d'obtenir un rendement élevé grâce à l'alimentation artificielle. Le prix de revient de la tonne de poisson alimenté artificiellement est beaucoup plus faible que celui du poisson n'ayant reçu aucun supplément d'alimentation.

Un régime équilibré, établi compte dûment tenu des aliments naturels existant dans les étangs, peut fournir un rapport appréciable en carpiculture. Si les résultats sont bons, il y a lieu de procéder à une analyse économique de manière à calculer le prix-seuil de rentabilité des produits alimentaires utilisés avant de procéder à une exploitation commerciale.

ASPECTOS ECONOMICOS DE LA ALIMENTACION DE LOS PECES EN EL MEDIO ORIENTE

Extracto

La alimentación de peces en una granja piscícola de tipo industrial es factible económicamente sólo cuando la granja tiene más de 20 hectáreas de extensión. Dadas las grandes inversiones de capital que precisa la piscicultura ésta sólo es económica si se pueden obtener elevados rendimientos de peces mediante la adición de alimentos. El coste de producción por tonelada de pescado alimentado es mucho menor que la del pescado sin alimentación adicional.

Una dieta equilibrada formulada teniendo debidamente en cuenta el alimento natural existente en los estanques, puede dar buenos beneficios en el rendimiento de la carpa. Si da buenos resultados deberá analizarse económicamente y averiguarse el precio del alimento que no determine pérdidas, antes de su empleo comercial.

1 INTRODUCTION

Before attempting an analysis of the economic aspects of fish feeding, the term should first be clearly defined. For the purpose of this paper fish feeding means feeding of warm-water fishes (mainly carp, Cyprinus carpio) cultured in ponds for human consumption on a commercial scale. These fish farms are self supporting economic units, not subsidized by the government in any way, and which produce fish at a price competitive with fish or other animal products.

This definition excludes from the scope of this paper small farm ponds or home ponds, which are found in many countries (though not in Israel). Fish feeding can be economical only when special care is taken to ensure the constant supply of feed and its daily routine application to the ponds. This is only feasible when the fish farm is above a minimum size, which seems to be about 20 hectares. It is possible, of course, that in some cases a smaller pond area may be successfully incorporated into a larger mixed agricultural farm where the pond management is efficient and organized well enough so that the fish will be regularly fed with good results. These cases, however, are few and exceptional.

In this connection it should be remembered that the general trend in agricultural techniques today is toward bigger farm units, where modern methods and equipment can be better utilized.

2 FEEDING WITH REGULAR FEED STUFFS

The first question to be answered when considering feeding fish in ponds is whether it is economic. This question may be put in a more extreme form: is fish culture economic without feeding? i.e., would fish yield from fish farms based on the pond's natural food alone (with or without fertilization) cover both capital and running costs, and still leave some profit for the owner? From the analyses given below it seems that, except for a few very fertile ponds, the answer is usually negative.

The fixed costs in fish culture are so high that they can be covered only by high fish yields. The invested capital for building of the ponds and the water system (which in Israel is about $2,000 per hectare), capital invested in gear, and costs of water, fertilizers, etc., are almost the same whether the fish are fed or not. There is some difference in labour costs, which are higher when fish are fed. This difference, however, is not proportional to the increase in yield obtained by feeding. The result is that the costs per ton of fish yield are higher without feeding than with feeding of the fish.

The average fish yield in Israel, in ponds where fish are fed, is 2,100 kg/ha, whereas in ponds without feeding (though fertilized) it is only 800–1,000 kg/ha. To obtain this increased yield, different feeds were used, such as certain cereal grains and oil cakes. The relative feeding coefficient, i.e. the amount of feed in kg per 1 kg of fish yield, is dependent on several factors such as the productivity of the pond and the feed used. In most cases, however, the average feeding coefficient was 2.5 – 3 for carp up to 600 g. Taking these data as a basis, the costs per unit area and per ton of fish were calculated for the two methods of culture, with and without feeding (Table I). The comparison between the costs per ton of fish cultured with feeding and that cultured on natural food alone, clearly shows that, in Israel commercial fish culture without feeding is uneconomical.

3 FEEDING WITH A BALANCED DIET

For some time it has been felt that progress in the feeding of carp is lagging behind the advancement in feeding of trout, salmon, and farm animals. In all these cases feeding of balanced diets has resulted in a considerable increase in yields. One should expect, therefore, that feeding carp a balanced diet would have a similar effect. This assumption gives rise to the following questions: (a) Considering that natural food is an important part of carp food, would feeding with a balanced diet cause an increase in yield or a lowering of the feeding coefficient? (b) What should be the composition and the price of such a diet? (c) Would the feeding of this diet be economical, i.e. would the gain in fish yield cover the added cost of feed, which would undoubtedly be higher than that of regular feeds used today? Some answers to these questions may be found in the results of experiments on carp feeding carried out in Europe (Janeček and Janeček, 1961; Merla, 1963; Müller and Merla, 1964; Kapach, personal communication) and in Israel (Hepher and Chervinski, 1965).

Table I

Calculation of costs per hectare and per ton of fish cultured in Israel with and without feeding

Table II

Calculation of the break-even price for protein-rich feed, when the increase in yield is 20 percent, and for conditions in Israel

	Amounts	Costs per ha	Costs per ton
Yield per hectare (Hectare per ton)	2,500 kg (0.4 ha)
Total costs using regular feed (Table I)		$ 1,466	$ 671
Additional costs of labour, marketing, etc., due to increased yield		4
Costs of regular feed for yield above ‘critical point’ (700 kg yield) × 2.5 (Relative feeding coeff.)	1,750 kg/ha	-100
Total costs without protein-rich feed		1,370	548
Difference in cost per ton yield			123
Protein-rich feed needed per ha when fed above the ‘critical point’ 1,100 kg yield × 2.5 (Relative feeding coefficient)	2,750 kg
Protein-rich feed needed per ton of yield (2,750 × 0.4)	1,100 kg
Break-even price for protein-rich feed

From these works it is clear that natural food is an important factor in the growth of carp in ponds. It would be a mistake, economically, to neglect this food which has qualitative as well as quantitative values. The protein and other nutrients in the natural food should be taken into consideration, and the supplementary diet added in such a way as to balance the natural food.

The protein content in natural food is very high, reaching about 60 percent of its dry matter (Schäperclaus, 1961; Mann, 1961). When natural food alone is utilized by the fish, part of this high quality protein is converted into energy. This source of energy could be provided even better by the carbohydrates in added feed, e.g. cereal grains. The protein in the natural food will thus be released to provide for further fish growth.

It is evident, therefore, that when natural food is abundant in the pond, a protein-rich diet would not have any advantage over cereal grain feeding. This was clearly shown in Hepher and Chervinski's experiments, where there was no effect of such a diet on yield when fish were small and their standing crop in the pond had not reached a “critical point” of about 800–1,100 kg/ha.

The situation is different, however, when the fish grow larger and their standing crop exceeds the “critical point”. (This point may be different in different ponds, according to conditions). The need for protein then increases, while its supply decreases. A shortage in protein develops, and it is at this point that the protein-rich diet affects yields. When fish are fed at this stage with a protein-rich diet their growth rate remains as before, or even increases, whereas when they are fed with cereal grains there is some growth inhibition, probably due to shortage in protein. The increase in yield achieved in Hepher and Chervinski's experiments was about 20 – 50 percent over the whole growing season.

It is possible to calculate the “break-even price” for the protein-rich feed, above which feeding with this feed is not economical, as returns in fish yield would not cover the additional cost for feed. Such a calculation for Israel conditions is given in Table II. Here the increase in yield due to feeding with protein-rich diet was taken as 20 percent only, though in some cases the differences in yield were greater. It should be remembered that in Israel the average yield of 2,100 kg/ha is attained in two growing seasons, each season of about 120 days giving about half of the yearly yield. Of this yearly yield, about 1,400 kg/ha (700 × 2) is received when the standing stock is still below the “critical point”, whereas the rest (about 700 kg/ha) is received when the fish are bigger and the standing stock is over the “critical point”.

According to Table II the “break-even price” is $112 per ton of protein-rich feed, when the yield increase is 20 percent. Obviously, if the price is higher, or the yield lower, it will not be economic. Such an analysis should be made for any diet before introducing it for commercial use.

In conclusion it can be said that new diets may result in higher yields of fish, just as they do in other farm animals. This justifies more basic, large-scale study of the subject. The results of this study, however, before being applied commercially, should be examined critically from the economic point of view.

4 REFERENCES

Hepher, B. and J. Chervinski, 1965 Studies on carp nutrition - the influence of protein-rich diets on growth. Bamidgeh, 17(2):31–46

Janeček, V. and V. Janeček, 1961 On the significance of percental presence of some proteinaceous and carbohydrate-containing feedstuffs in feed mixture for carp with utilization of so-called surrogate feedstuffs. Pr.VÚRH Vodňany, (1):48–72

Mann, H., 1961 Fish cultivation in Europe. In Fish as food, ed. by G. Borgstrom, London, Academic Press, pp. 77–102

Merla, G., 1963 Die Rolle der Naturnahrung als Eiweissquelle bei der Erzielung von Karpfenerträgen. Dtsch.Fisch.-Ztg., 10(3):77–82

Müller, W. and G. Merla, 1964 Die Bedeutung des Eiweissgehaltes der Karpfenfuttermittel für den Karpfenabwachs unter Intensivbedingungen. Dtsch.Fisch.-Ztg., 11(9):273–7

Schäperclaus, W., 1961 Lehrbuch der Teichwirtschaft. Berlin, Paul Parey, 582 p.