ISRAEL

by

Dan Mires
Chairman of the National Board of Aquaculture
Ministry of Agriculture
Hakyriah - Tel Aviv

INTRODUCTION

For the last four decades Israel's fish farms have oriented most of their efforts to supply all the demands of the local market. In most cases they have indeed succeeded to do so. Over 50% of the total fish consumption is produced in fresh water fish ponds. For the last 6 years the inland fisheries production has remained stable and it seems that there are little chances to change this trend as long as only traditional live carps and fresh frozen tilapias will be produced. Lately, local consumers have shown a greater interest in canned and processed products as well as in imported marine fish (Sarig 1985). These late developments have lead the Inland Fisheries Department and Fish Breeders Association to change their production policies. Since 1979, most development funds and research efforts in aquaculture have been mobilised for the development of exportable products and for studies aimed to intensify new and traditional production systems. Two new processing plants have been built by the Fish Breeders Association and the main marketing cooperative to meet the changing trends of local and foreign markets. These efforts are now begining to produce positive results.

I FISHERY BIOLOGY AND MANAGEMENT

Three new aquatic cultures are now being developed, freshwater prawns M. rosenberghii, eels A. anguila and ornamental fish. Intensive production systems for tilapias are also being studied and modern processing systems are being developed both for carps and tilapias.

I. Freshwater prawns

Since 1983 three new hatcheries have been built. Altogether 6 hatcheries are now in operation. The production capacity has rised from 4 million P.L's in 1982 to 8 million in 1985 and the nursing capacity from 1.7 million juveniles to 5 million respectively. With the introduction of substrates in all nursing facilities the stocking densities were increased from 1.0 P.L liter^-1 (without substrates) to over 6 P.L's liter^-1 and the survival rates from ± 40% to 55–75%. All hatcheries and most nurseries have installed a closed water system.

New monoculture and polyculture managements are continuously being tested in two of our research stations as well as in some advanced farms. Experiments in monoculture are usually done in small ponds (0.4 – 0.5 ha.). The main topics that were covered were:

1. The effect of substrates on stocking densities and yields of prawns (Z. Raanan et.al. 1984)
2. The effect of various culling managements on size repartition of prawn populations (D. Cohen et al. 1983)

3. Monosex culture of male prawns (Z. Raanan et al. Unpublished)

These experiments showed that the addition of substrates together with three or four cullings of bigger prawns, during the summer, increased the total yield as well as the percentage of > 30 grs specimens for which higher prices can be obtained. All male populations produced similar results.

In polyculture, various stocking combinations were tested, all of which showed that growth and survival of prawns and fish are independant Prawns were only influenced by their own stocking rate. In these tests a daily increment of 40 kg/day of fish and up to 7.2 kg/ha of prawns were obtained (Wohlfarth et al 1985). Higher densities produced higher yields but smaller animals and vice versa.

In other experiments done in farm conditions an attempt was made to combine relatively high stocking densities of prawns and sex inversed tilapias (Mires 1986 unpublished). Two cullings of > 30 gr prawns were done after the fish were separated from prawns with a suitable net. Yields as high as 1200 kg/ha of prawns and 3000 kg/ha of tilapias were obtained in these commercial ponds.

Polyculture of all male populations of prawns and fish showed similar trends to those obtained in monoculture.

An early grading of juvenile prawns and the stocking of different size groups also improved yields and size repartition of these prawns (Karplus et al unpublished ).

2. Eel culture

The development of eel culture in Israel is still in it's initial stages. The rational behind this venture is:

1. An important demand for eels seems to exist in some european countries.
2. Israel's climate is suitable for eel culture.

3. Water shortage as encountered in Israel can be overcome with closed or semi-closed water systems.

Two years were required to master indoor nursing techniques. During this period, three new eel nurseries were constructed in private farms in which 500 kg of elvers can be nursed. In 1986 three grow-out units will be operated, one in Genossar research station and two others in private farms.

Further developments in eel culture will depend on the professional and economic results of the experimental facilities.

Most of the eel farms are planned to be built in the Upper Galillee region where they will be supported by the regional research station. The main efforts during the next few years will be concentrated on the development and management of intensive production units, preparation of feeds and the processing of various eel products.

3. Tilapia culture

In Israel, monosex tilapia cultures are well established. Yet, the seasonal fluctuations of the marketed fish strongly antagonise the requirements of processing plants who seek a continuous inflow of raw-material and outflow of products. To overcome this problem, new intensive production units are now being tested. These include circular race-ways of different dimensions with closed or semi-closed water systems from which fish can easily be harvested at any time. The study of the nutritional requirments of tilapias and the development of cheap but effective feeds.

Research stations as well as private hatcheries are still continuing their search for new strains from which fast growing hybrids can be produced. Red tilapias are also being tested within this same framework.

4. Ornamental fish

During the last five years, several new ornamental fish farms have been built. Most of them produce cold water species which are being exported to Europe and the U.S.A.

Most of the production units are in private hands but they have all been supported by governmental development funds. At this stage most producers are still steadily increasing their production. The total income from these cultures is now estimated to be ± 1.0 million US dollars. Yet, very little is known about the true potential of this industry because international competition is constantly growing. In the near future no major development is planned in this sector.

5. Intensification of cultures

The ever growing competition for water in agriculture and the increasing cost of labour have brought the National Board of Aquaculture to the decision that “ Improvement of productivity of all culture systems” should be considered one of the most important aims in israeli aquaculture today. The two main limiting factors in this process are the gradual accumulation of nitrogen compounds in ponds and oxygen. Two research groups that have been studying these aspects in ponds as well as in race-ways have recently brought their findings to the fish breeders knowledge. These are now paying more attention to amonia and nitrite levels in their culture units and are learning how to cope with these factors before their crops are endangered. The installation of new and improved biofilters have markedly improved the efficiency of closed water units. The future potential of these systems is now being studied. If proved economically profitable, they will undoubtedly be used for a large variety of aquatic cultures.

Since the introduction of mechanical aerators, ten years ago, there has been little improvement. Comparative tests done with practically all existing types of aerators showed that the “paddle wheel” types are the most efficient, relative to the energy they require.

II FISH CULTURE AND DISEASES

It was anticipated that the intensification of cultures would lead to a fluxion of fish diseases. For the last five years, special attention has been payed to the study of various stress factors and their effects on fish. Simultanously, the effectiveness of new treatments is continuously being tested.

Compared with the past, when fish pathology in Israel dealt mainly with parasitology, bacterial diseases are now becoming more common. The introduction of several exotic ornamental fish which all seem to be more sensitive to both parasites and bacterial diseases only accentuates the need for more intensive research in both these fields.

The few restrictions on importation of fish have so far been quite inefective and several exotic parasites have thus been imported, mainly through ornamental fish. Harsher quarantine regulations will therefore have to be enforced in the near future.

III FISH AND POLLUTED WATER

Inland fisheries in Israel depends mainly on the following water sources:

1. Sporadic flows following heavy rain falls.
2. Rivers.

3. Wells.

Out of these three only river water is sometimes polluted, mainly by rural sewage. The main consumers of river water are farms located along the northen part of the Jordan river which is usually free of pollutants. Nevertheless, pollution occurs in ponds when pesticides sprayed over fields are accidentally blown into neighbouring water bodies. On such occasions partial or total death of all the ponds population can occur When laboratory tests are able to detect traces of these pesticides, farmers are indemnised by the owner of the field or by the company in charge of the spraying.

IV PRODUCTION STATISTICS

The following section was extracted from ‘Bamidgeh’ Journal “Fisheries and Fish Culture in Israel 1984” (S. Sarig 1985).

I Israeli Fisheries

The total Israeli catch for 1984 was 21, 364 tonnes, 4.2% more than in 1983. This increase was observed in all fisheries except Lake Kinneret where the catch was 5.3% lower than in the previous year.

In the other sources fluctuation in catch were not significantly different compared to 1983, ranging between 2.0 to 6.3 percent, except in the trawl fishery which increased this year's catch by 303 tonnes, more than 30%. This increase in the total Israeli catch is the first after 4 years of continuous decline (Table 1)

Table 1. Israeli Fisheries in 1980 – 1984, according to Sources.

As in all previous years the per-capita consumption remained stable around the 10kg level, although this year's level went down by 0.2 kg-2%, as against 1983. The drop in consumption and the increase of catches caused, together, a decrease in the part of imported fish products from 51% of the total per-capita consumption in 1983 to 45% this year. Another interesting phenomenon of this year, is the increased demand for “canned and processed” products as against “Live, fresh and frozen”-38.4% this year instead of 32.7% in 1983.

2. Fish culture

No significant changes in the number of farms and pond area took place in 1984 compared to 1983. However, the total quantity of marketed fish as well as the average yield per hectare increased drastically. The total quantity of marketed pondfish excluding trout, eel and prawn increased by 406 tonnes, 3.7% as against 1983, and reached the production level of 1982 (Table 2). The average yield per ha. reached 3680 kg, 5.1% more than in 1983. This year's yield, was the highest for the last 10 years (Table 3).

Table 2. Fish species marketed from fishponds in 1975–1984.

Table 3. Fishponds, area and yields of marketed fish in 1975–1984

In addition, the two trout farms operating in the country on an area of approx. I ha, produced 235 tonnes, as against 205 tonnes in 1982 from the same area.

Machrobrachium rosenberghii production increased to 35 tonnes as against 23 tonnes in the previous year and 13 tonnes in 1982. All prawns were exported.

The demand for processed pondfish as fillets or cleaned and frozen continued to increase and reached 11.4 % (1292 tonnes) of the total marketed this year as against 10% (1078 tonnes) in 1983.

3. Fish species marketed

The demand for common carp decreased this year very significantly by 844 tonnes, 11%, as against 1983. This was the lowest figure of carp marketing for the last 10 years. Tilapia replaced markedly the place of carps, reaching, almost 3100 tonnes, 1017 tonnes, 49% more than in 1983. Tilapia represented this year 27% of the total pondfish marketed.

Two size groups of tilapia are marketed from ponds. The larger size of 500–700grs. are in great demand. These are mainly males from hybrids or sex revearsed stocks. Another group of 250–300 grs. are sold at a lower price and have a different class of consumers.

The total quantity of Mullets marketed in 1984 was 1217 tonnes, almost the same as the previous year. But, the part of each source changed. The pond mullets increased by 132 tonnes. The Mediterreanean catch increased by 110 tonnes, 38%, but the Lake Kinneret catch went down by 69%.

V. BIBLIOGRAPHIC REFERENCES

Cohen.D., Z. Raanan, U. Rappaport, Y. Arieli. The production of freshwater prawn Macrobrachium rosenberghii (De Man) in Israel: Improved conditions for intensive monoculture - Bamidgeh. 2, Vol 35 (1983) 31–37.

Raanan. Z, D.Cohen, U. Rappaport, G.Zohar. The production of the freshwater prawn Macrobrachium rosenberghii in Israel: The effects of added substrates on yields in a monoculture system. Bamidgeh.2.Vol. 36 (1984) 35–40.

Sarig. S., Fisheries and fish culture in Israel 1984. Bamidgeh. 3. Vol. 37 (1985) 63–76.

Wohlfarth.G,G. Hulata, Karplus. Y, and A. Halevy. Polyculture of the freshwater prawn Macrobrachium rosenberghii in intensively manured ponds, and the effect of stocking rate of prawns and fish on their production characteristics. Aquaculture, 46 (1985) 143–156.