On Farm Trial

Enhancing Fish Farm Productivity Through Improved Management (A Case Study in Egypt)

Abdel Rahman A. El Gamal

Senior Aquaculture Scientist ICLARM Regional Research Center for Africa and West Asia Abbassa, Abou Hammad, Sharkia, Egypt [email protected]

ABSTRACT

During a 3-week training program held during 1999 on field application for fish culture technology in Egypt, it was noticed that a significant enhancement in pond productivity could be achieved mainly through improved pond management. A pilot farm was chosen to carry out a demonstration trial in a 2.1 ha pond. Five thousand, six hundred mullet fingerlings, Mugil cephalus, and 39,000 all-male young-of-the-year Nile tilapia, Oreochromis niloticus were stocked in the pond. Artificial feed, 25% protein was used. Fertilizers (organic and mineral) were only used whenever needed based on water analysis and field observations. The overall quantities of chicken litter and superphosphate used were only 200 kg each for the whole trial during the entire season. Sampling of fish as well as analysis of main water quality variables were carried out throughout the trial. Noticeable mortality in tilapia stocks took place. This mortality was attributed to the relatively high salinity levels that reached 18 g/l and stayed in that range for a considerable period; whereas mullet was never affected. Feeding was stopped for extended periods because of stress and mortality caused by salinity limiting the feeding days to 138 out of 232 days (the total length of the trial). The total quantity of feed used amounted 8,590 kg. The gross fish production of the trial that was 6,395 kg (3,045 kg/ha) was about twice as much as previously obtained by the same producer. The economic analysis of the whole trial was very positive with a total revenue of US$15,206 against an overall cost of US$ 8,384 indicating the probability of at least doubling the profit compared to previous years. The proper use of production inputs and its relation with the culture environments has been focused on throughout the entire trial. The value of feed conversion ratio, which was 1.36:1, demonstrates the efficient contribution of combined use of feed and fertilization in fish production at this level of management. The overall findings illustrated the benefit of working directly with farmers to relate what has been taught in classroom to farm practices. INTRODUCTION

The contribution of aquaculture production in Egypt is progressively increasing, reaching 139,389 tons in 1998, representing about 26% of the total fish production in that year (545,593 tons) (GAFRD, 1999) compared to about 1.9% in 1980 (CAPMS, 1981). The main cultured species, tilapia and mullet, contributed about 38% and 20%, respectively, to the total aquaculture production in 1998. (GAFRD, 1999).

Although various types of fish farming are being practiced, earthen ponds that covered about 66,000 ha in 1998 is still, by far, the main production method in aquaculture in Egypt where mullet and tilapias are the major farmed groups (El Gamal 1997).

Because nature is the main source for mullet fry, Mugil sp., their catch varies from one year to another. For example, the catch was as low as about 60 million fry in 1979/1980, peaking to about 145 million in 1986/1987 then declining afterwards to about 130 million in 1997/1998 (GAFRD 1999). Therefore, the availability of fingerlings to farmers is uncertain. Moreover, the mixing of target species with undesired ones is always a possibility as a result of overlapping between collection seasons of different mullet species. On the other hand, there has been a remarkable development led by the private sector in tilapia hatcheries. This has been driven by the excellent status of tilapia market as well as the reliability in obtaining their seed compared to the uncertainty in regard to mullet fry.

Constraints to aquaculture development have repeatedly focused on physical issues including the availability of appropriate quality of main production elements such as water, land, feed, seed, etc. Training of fish farmers was not fortunate enough to be on the list of needs most of the time even though the training will be needed more in the view of the current intensification trend in farming practices. This is why the target group to our first training course was 14 fish producers from Fayoum Governorate.

FARM TRIAL

Based on discussions with the trainees participating in the training program “Field Application for Fish Culture Technology in Egypt”, which took place in March 1999, it was noticed that a significant improvement in pond productivity could be achieved mainly through the improvement in pond management with wiser use of production inputs.

In order to obtain field information on fish farming in Fayoum, it was necessary to have a private fish farm in this trial. A main criterion in selecting the farm was to represent the prevailing environmental conditions in most of the other fish farms in that region. The importance of acquiring technical information needed for this project was emphasized keeping in mind the educational background of our collaborators.

It was also necessary to collect as much information as possible in relation to the target region as well as on the contributing farm. Water quality characteristics and the practices used in pond management were the key information targeted. The history of farm productivity was also obtained. An average production of 1400 kg per hectare per year was considered a good recent estimate for the collaborating farm and other farms in that region.

Collaborating Farm

Our collaborating farm went through a series of culture trials consulting the available resources for information as well as through self-learning process. Therefore, several aquacultured species have been tried for culture starting 1989. European sea bass, Dicentrachus labrax, all-male red tilapia, eels, Anguilla sp. and freshwater prawn, Machrobrachium rosenbergii, have been all tried for their farming suitability. For one reason or another regarding the quality of seed, rate of survival, management practices, marketability, and/or pond productivity, only mullet, Mugil sp. and tilapia, Oreochromis sp. appeared as the fish best fitting the farming conditions in the farm.

Before initiating the pond trial, a preliminary assessment for the farm condition was obtained. Table 1 shows the water analysis for water source as well as for several cultured ponds on 15 March 1999.

Table 1. Preliminary water quality analysis for the collaborating farm and water source on March 15, 1999. g S m H m A m a T c S v m / a e o l l g g g a a l k c

Temp. pH NH4 NH3 NO3 t

Water body i / / / i a c a n l r l l l l h l a d i

i t b i n y n l C mg/l mg/l mg/l d i e t e i y

s k P s

Water source 20 8.5 1.1 0.18 0.18 6 850 387 0.58 27 Pond 3 20 8.5 1.4 0.23 0.62 9 800 337 0.64 15 Pond 8 21 9.0 1.1 0.38 0.21 7 800 340 0.52 22 Pond 11 22 9.0 1.2 0.30 0.55 17 940 317 0.88 9 Pond 12 21 8.5 1.1 0.18 0.30 7 700 272 0.56 22

The total area of the farm where the trial took place is about 18.5 ha made up of 15 ponds; 12 grow out and 3 nursery ponds. The acreage for production ponds ranges from 0.6 to 2.9 ha. The farm began its operation in 1984 with 2.5 ha and progressively expanded to reach its current acreage. The previous annual production in the farm as mentioned was about 1400 kg per ha. Feed components were brought to the farm where manual mixing took place before feeding. Only in the last part of the previous farming season, manufactured pelleted feed was used. Chicken litter was the source of organic manure used in the farm before. Chemical fertilizers used included superphosphate and urea.

Pond no. 2 with a total area of 2.1 ha was assigned to this trial. The average water depth in the pond is about 120 cm. Agriculture drainage water is the only water source used in the farm and the trial pond. The pond was filled by gravity through 8-inch pipe while draining was done by pumping using centrifugal pump with 5” intake. The Concept of the Trial

Recording of the variables affecting the productivity of the trial was given high priority. However an over riding consideration was to ensure good production during this first season. This would assure confidence needed for further work with other farmers in the region. The fundamental issue was to provide the technical assistance required for the producer who managed this trial pond as a part of the entire farm.

Production Inputs

Fish Fingerlings

Wild caught mullet, especially Mugil cephalus, is considered a key species in Fayoum fish farms. The trial pond was stocked with 5,600 mullet fingerlings of about 10-g average weight in May 1, 1999. There was a considerable variation in the initial size.

In order to ensure the purity of Nile tilapia, Oreochromis niloticus, all-male tilapia fingerlings were produced in the facilities of ICLARM Regional Research Center at Abbassa. Two batches of young-of-the year fingerlings were provided to the trial during May and June 1999. The first batch included 14,000 fingerlings with 0.8-g average weight, while the second batch included 25,000 of 0.5-g fingerlings. Tilapia fingerlings were transported to the site of the trial in transportation tanks supplied with oxygen. Preliminary acclimatization was carried out during the 5-hour trip using pond water, while more acclimation was carried out upon the arrival to the farm.

Feed and Fertilizers

The farm was responsible for providing the feed and fertilizers (organic and mineral). The manufactured feed, 25% protein according to factory label, was analyzed once and was found to contain 29% protein. Chicken litter was purchased from local layer operations. Superphosphate was acquired from local market.

Sampling

Fish Sampling

During the course of the trial, which extended from May until December 1999, seven samplings were carried out on June 20, July 1, August 3, September 5, October 9, November 10 and December 23. This was done to assess the condition of the fish as well as to adjust feeding rates. Sampled fish were measured to the nearest millimeter and weighed to the nearest 0.1 gram. Sample size was not pre-determined. Therefore, there was a considerable variation in sample size depending on some environmental as well as behavioral factors also related to the effort put in sampling process. Therefore, the number of fish being sampled was 40, 39, 65, 56, 41, 352 and 90 during the seven samplings. Fish were sampled using a net stretched for a considerable distance around feeding ground. This was done using a small canoe. During the day of fish sampling, water samples were also taken for chemical and biological analysis either on the site or carried to the laboratory depending on the type of the analysis. Clinical examination was done once when mortality extended over a relatively long period.

Up to the August sampling of fish, tilapia specimens could be related to their original batches with confidence according to size. Afterwards, the two original populations began to overlap. The method of sampling was found somehow effective with tilapia but it was much less effective with mullet, which mostly managed to escape the net. Their average size was estimated over most of the samplings. When fingerlings of green tilapia, Tilapia zillii were found in the pond, locally made traps were used to collect and eliminate these fingerlings.

Water sampling

Dissolved oxygen was measured by the pond operator using a YSI 58 oxygen meter provided to the farm in the second half of August. Water sampling was routinely carried out in parallel with fish sampling whereas HACH kit NI-8 was used for the analysis of total ammonia. HACH kit 17-N was used for pH measurements, and YSI 33 was used to measure salinity and electric conductivity. For total phosphorus, nitrogen, alkalinity and hardness water samples were taken to the laboratory and analyzed according to the standard methods (APHA, 1985). Secchi disk was used throughout the study for transparency estimation.

Biological analysis was done to assess the nature of plankton communities in the pond. An 80-micron plankton net was used to collect samples. Zooplankton was fixed using 40% formalin then microscopically counted using a Sedgwick-Rafter counting chamber. In regard to phytoplankton, the water sample was treated with lugol’s solution, then counted microscopically as in zooplankton. Water analysis data are presented in Table 2.

Over the period 17-19 September, a detailed analysis was carried out using a data logger (Hydrolab Mini Sound) provided by HARZA Consulting Engineers and Scientists. Measurements for temperature, dissolved oxygen, salinity, total dissolved solids, and pH were obtained and recorded at predetermined 15-minute intervals during this course of analysis. The data are presented in Table 2.

When mortality occurred, live fish samples were collected and brought to the laboratory for diagnosis. However, no bacterial or parasitic infection was found.

Fertilization and Feeding Strategies

In order to determine appropriate feeding rates, several parameters were considered; the condition of the fish and the water quality being the most important. Fertilization rate was realized to be an area of special sensitivity because of the quality of water entering the farm and its contents of nitrogen and phosphorus. According to the recommendation of Hepher and Pruginin (1981), a phosphorus concentration of 0.5 mg/l and 1.4 mg/l of nitrogen was attempted. As mentioned earlier, fertilizers used were the chicken litter as the organic and the superphosphate as the inorganic one. Artificial feeding was started on May 30 and continued until the 25th of December. Daily feeding allowance was applied on two equal aliquots with about 3 hours interval. Four 1.5-m length x 1-m width x 0.1-m depth feeding trays were distributed along the pond axis as the trial started. Trays were raised above pond bottom to maintain a position of about 30 cm below water surface. The bottom of feeding tray was made of fine mesh screen. As the growing season progressed, the number of feeding trays was not adequate and four more trays were then added. The feeding trays were inspected prior to the second feeding. If all feed was consumed, the second feeding was provided as planned, otherwise, the amount was reduced or withheld.

Water Management

Water exchange was done to compensate for seepage and/or evaporation and to maintain salinity levels within a safe range. During summer months when evaporation was at its maximum, the pumping capacity was not sufficient to maintain salinity as targeted. By November, the rate of water exchange was able to offset the rising trend in salinity because of evaporation as the water temperature was declining. On the average, exchange of about 5% of the pond water volume was allowed every day. Only in one occasion, when field testing revealed high level of ammonia (NH3) present in pond water, an immediate major water exchange was carried out. Locally manufactured aerators run by a diesel engine were used in the pond following the same practice used in previous season.

Table 2. Water quality analysis during the growing season of the pond trial in Fayoum (from June until December 1999).

Parameter/date June July Aug. Sep. Oct. Nov. Dec. Parameter unit 20 01 03 09 09 10 23 pH 8.8 8.6 8.8 9.0 8.9 9.1 8.5 Temperature* C 26.0 28.5 24.0 25.5 25.0 21.0 17.0 Salinity g/l 18.0 17.9 14.0 12.0 18.0 10.0 08.0 Total Hardness mg/l 1100 730 590 1230 690 450 > 450 Total Alkalinity mg/l 225 230 300 220 375 375 334 Total ammonia mg/l 3.34 2.8 nitrogen

Nitrate (NO3) mg/l 1.2 0.9 Total available mg/l 0.4 0.58 0.038 0.13 phosphorus Secchi disk cm 20 19 18 19 40 Phytoplankton org./l 46800 8990 count Zooplankton org/l 500 542 count

Water analysis using data logger 11:00 AM Sep. 17 to 11:00 AM Sep. 17 to 10:45 AM Sep. 18 10:45 AM Sep. 18 Min. Max. Min. Max. Dissolved oxygen mg/l 4.99 16.7 7.6 15.5 Temperature C 25.5 29.9 26.4 28.8 Salinity g/l 17.3 Total dissolved g/l 18.0 solids Secchi disk cm 18.0 pH 8.4 * Temperature was measured 25 cm below water surface at 9:00 – 9:30 AM

Main Production Indicators

Fertilization was carried out based on the water quality analysis especially its contents of various nutrients especially phosphorus and nitrogen. This resulted in a very light fertilization system. For example, the pond was fertilized using only 200 kg of chicken litter throughout the whole trial, and that was done very early in the season during June and July. Superphosphate, which was the only mineral fertilizer used, was provided 4 times with a total quantity of 200 kg to the pond during the entire growing season with its final application in September 29. The relatively high rate of water renewal has resulted in this light fertilization regime.

Salinity was the most important element affecting pond productivity because of its effect on tilapia in regard to growth and survival. Over the entire growing season, salinity fluctuated considerably (Table 2). For example, the salinity of the incoming water was 6 g/l in March 15, 1999, before pond stocking and increased to 19 g/l throughout the period 22-27 July. Out of 8 salinity readings over the period from June 18 to July 13, the lowest salinity concentration was 13g/l. Afterwards, salinity has declined to 12 g/l in the 9th of September then increased to 18 g/l in October once again. Even in September, the analysis using data logger revealed salinity levels in the range of 17-18 g/l over the 48 hours of measurements (17-19 September). The pond did not have the appropriate level of salinity (for tilapia) until December 1999 when salinity dropped to 8 g/l. As expected, the stressful effect of these levels of salinity was specific to tilapia stocks and not to mullets, the euryhaline group. This effect could be shown by differential recorded mortality which tilapia stocks have experienced over 72 days (605 specimens) compared with mullets that had no recorded mortality during the whole season. Avella and Doudet (1996) reported mass kill of two strains of O. niloticus upon the direct transfer from freshwater to 20 ppt salinity with no pre- acclimation. This may explain the effectivness of the acclimation for the first batch of tilapia where salinity was below 10 g/l. The same protocol of acclimation seemed inadequate with the second batch of tilapia as the salinity was rising in June. In general, the recorded mortality for tilapia was less than 5 per day in 39 days. Because tilapia were under salinity stress for extended periods, feeding was stopped at several times in order to maintain the culture environment as healthy as possible. For example, the fish were fed only 138 days throughout the entire feeding period from 2 May until the harvesting in December 1999. During July alone, feed was not provided for 16 days. It may be worth mentioning that 110 kg was the largest daily feeding allowance given to the trial pond. This was done for only 4 days during October and November.

With the exception of salinity, the water quality parameters remained within acceptable ranges most of time throughout the trial. Only three times were fish seen surfacing early in the morning because of low dissolved oxygen; with no mortality. Also, high level of water exchange was employed to bring in ammonia concentrations to a safe level.

Out of 32 early morning measurements during the period August 25 until October 10, only once dissolved oxygen dropped to its lowest recorded level at 5:30 AM (1.7 mg/l). This coincided with high water temperature (29 oC).

Based on the readings of dissolved oxygen, the aerators used were not adequate although they helped in some situations. If the operation of these paddle wheels had been linked to the oxygen measurements instead of routine operation, the operation hours could have been significantly reduced.

Production and Marketing

The overall pond production is presented in Table 3. Unexpected delay in the final harvesting could not be avoided due to marketing difficulty in all fish markets beginning October 1999. However, to avoid any risk of cold during winter on tilapia survival, it was agreed to harvest the trial during the last week of December regardless to prices. By then, the farm gate price was slightly improved but still much lower than that in the previous three years. Before, the final harvesting, there were small quantities of fish being sold either because of sampling stress or the green tilapia trapped, which surprisingly had a good market.

Table 3. Performance indicators* of the study pond throughout the growing season during 1999.

Stocking Phases Achieved Date Number Total I II III IV V VI VII weight (kg) Estimated increase in fish biomass (kg/pond) Mullet May 1 5,600 56 123 71 250 268 244 158 315 Tilapia 1 May 2 14,000 11.2 279 497 696 380 398 646 Tilapia 2 June 5 25,000 12.5 33 56 456 816 376 182 201 Biomass increase 435 624 1402 1464 1018 986 516 6333 (kg/pond) Quantity of feed 230 170 530 1715 1905 2890 1150 8590 used (kg) Feed conversion Less Less Less 1.17 1.87 2.90 2.03 1.36 ratio (feed:fish) than than than 1 1 1 TOTAL 44,600 79.7 Number of 18 9 14 26 23 30 18 138 feeding days * Values on biomass increase are based on sampling of tilapia and/or estimated growth for mullet as well as estimated survival for the three groups Phase I: from stocking up to June 20 Phase V: from September 05 to October 09 Phase II: from June 21 to July 01 Phase VI: from October 10 to November 10 Phase III: from July 02 to August 03 Phase VII: from November 11 to December 23 Phase IV: from August 04 to September 04

Expected Versus Achieved

As shown in Table 4, there was considerable difference between what was achieved and what has theoretically been expected. This difference was negative in regard to tilapia, which could be explained by higher actual mortality in the second group of tilapia than recorded since it was stocked in water with higher salinity compared to the first group. Also, using feed during sampling probably attracted a larger number of larger sizes. On the other hand, because mullet was not attracted to sampling grounds, the final harvest revealed a higher yield of mullet than what has been estimated.

Table 4: Expected versus achieved production measured as kg/pond. Expected (kg/pond) Achieved (kg/pond) Tilapia Production (grade 1*) 2905 Tilapia Production (grade 2*) 2129 Total tilapia production 5034 Total tilapia production 4255 Total mullet* production 1474 Total mullet production 2140 Total pond production 6508 Total pond production 6395 What has achieved to what has been expected 98.3% for total production What has achieved to what has been expected 84.3% for tilapia production What has achieved to what has been expected 145.2% for mullet production * Tilapia with an average size of >200 g is considered grade 1, while grade 2 represents tilapia with average size >100 g up to 200 g. All mullet crop was of grade 1. Tilapia crop was marketed as a combined grade.

Economic Analysis

The economics of this trial was its main factor of justification. The direct costs of production inputs were obtained out of the trial records. The cost of pond lease was estimated according to the current lease values in the same location. Labor cost was placed directly as operation cost, while the share of the pond in the overall labor and management was done on proportional basis in regard to acreage of the farm. Market price for tilapia fingerlings was included for the tilapia provided by ICLARM. As presented in Table 5, the total cost of the trial reached US$ 8,384 against US$ 15,206 as total revenue. Table 5. Preliminary economic analysis for the production trial held in Fayoum, Egypt.

Cost Revenue Item US$ Item US$ Feed and fertilizers 2,758 Tilapia sale 7,653 Labor and management 1,094 Mullet sale 7,553 Fuel 299 Maintenance 201 Labor for harvesting 459 Pond lease 1,618 Tilapia fingerlings 1,176 Mullet fingerlings 485 Depreciation 294 TOTAL 8,384 TOTAL 15,206

CONCLUSION

Out of the difficulties the trial has experienced in the current season, those related to the high salinity levels are the ones that upset the performance and survival of tilapia the most. In addition, the farm gate price for tilapia and mullet was about 15% lower than previous years. However, the return of this pond was still attractive. Because the main goal was to achieve the best economic production possible, the largest biomass was not the only parameter attempted. The moderate contribution of feed to the overall production costs (< 33%), and the efficient feed conversion ratio (1.36:1) clearly demonstrates to what extent the natural fertility contributed to the overall production.

Theoretically, higher fish yields could be achieved using higher levels of inputs. However, unless the additional revenue compensates for the additional costs, there is no point in targeting that.

At this level of management where the contribution of direct operation inputs, such as feed, was moderate, the overall fish production in regard to biomass and size grade seem the most important single factor that determines the magnitude of the profit. Therefore, even the economics of previous years operation for the collaborating farm, and hence the trial pond is not available, the net profit of the current trial most likely will exceed the two-fold magnitude of profit compared to the previous experience of the farm. In general, more farm trials are needed to refine and utilize these findings to establish the most economic production scheme in such dynamic systems.

In brief, on-farm trials are an effective means for working directly with producers through an actual application and testing the production technology taught in the class room. To build on last year’s results, we are planning with the Multi-Sector Support Programme (MSSP) to conduct another trial on the same farm as last year and, in addition, we are selecting another farm in that region that has different water quality. The number of fish farmers who expressed their willingness to join this program this year, indicates that, by working under different production conditions, more farms will be able to benefit from the results. The outcome of this trial demonstrates how a significant benefit to Egyptian aquaculture could be achieved through the development of human resources and through the technology transfer approach.

ACKNOWLEDGEMENT

Considerable support was provided to me throughout the implementation of this project. First, I would like to thank Eng. Mohamed Gouda, the owner of the pond for making his pond available to conduct this trial and for accepting to share with farmers in the region these findings especially the economics of it. My colleagues in ICLARM gave considerable support to this trial beginning from fingerling production to the sampling program until harvesting. To them all, my sincere thanks. I would like to acknowledge the support given by MSSP for supporting the workshop held during March 2000 and for the continuation of the support for demonstration activities at wider scope during year 2000. I would like also to thank HARZA Consulting Engineers and Scientists for making available their data logger when there was a need to assess the change in water quality main parameters at a particular time. Finally, I would like to acknowledge the support and care Dr. Roger Rowe ICLARM Deputy Director General has given to this trial.

REFERENCES

APHA (American Public Health association). Standard Methods for the Examination of Water and Wastewater. 16th edition. 1985. Avella, M. and T. Doudet. 1996. “Physiological Adaptation of Oreochromis niloticus and O. aureus to Salinity”. Pp. 461-470. In: R.S.V. Pullin, J. Lazard, M. Legendre, J. B. Amon Kothias and D. Pauly (eds.). The Third International Symposium on Tilapia in Aquaculture. ICLARM Conf. Proc. 41, 575 p. Central Authority for Public Mobilization and Statistics (CAPMS). 1981. Fisheries Statistical Yearbook, Statistics of Fish Production in Egypt, Arab Republic of Egypt: 1980. CAPMS, Cairo, Egypt, 52 p. El Gamal, A. A. 1997. “Egyptian Aquaculture: Status and Development Requirements with Special Emphasis on Tilapias and Their Potential in Aquaculture”. In: (Fitzsimmons, K. editor), Proceedings from the Fourth International Symposium on Tilapia in Aquaculture, Vol. 2, Pages:441-452. General Authority for Fish Resources Development (GAFRD). 1999. Statistics of Fish Production. GAFRD, Ministry of Agriculture and Land Reclamation, 175 p. Hepher, B. and Pruginin, Y. Commercial fish farming. New York, J. Wiley, 1981, 261 pp.