FI:TCP/PAK/6657
Field Document No. 3
January 1988

FIELD REPORT - AQUACULTURE CONSIDERATIONS

by

K. G. RAJBANSHI
Aquaculture Specialist

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1. INTRODUCTION

The Consultant Aquaculture Specialist was not able to arrive in Pakistan on the dates agreed to allow an overlap with the visit of the Project Coordinator, as the air ticket did not arrive in time. Upon receiving a telex from the FAO Representative, Pakistan, dated 11 October, the FAO Representative, Nepal, made a new ticket available. The Consultant was therefore not able to begin his mission until 14 October. After reporting to the office of the FAOR at Islamabad on 14 October, a brief meeting was called with the Project Coordinator, Dr. I. G. Dunn, and the Consultant Aquaculture Engineer, Mr. E. Woynarovich. The various activities under the present consultancy was discussed as per memorandum (Appendix A). After completing financial formalities at the office of the FAO Representative, Islamabad, the Consultant reached his Lahore duty station on 17 October.

2. ITINERARY

The Consultant Aquaculture Specialist undertook his assignment in Pakistan from 14 October to 13 November 1987, with the following itinerary:

3. ACTIVITIES

The Consultant carried out the following activities and made the following observations:

• visited Fish Hatchery and Nursing Unit, Mangla, as a follow-up programme to the previous mission;

• worked closely with the Aquaculture Engineer Consultant in planning the hatcheries and fish farms;

• undertook field work in order to prepare cage fish culture recommendations, in close consultation with the Limnology Consultant.

• procured chemicals for medical use in the fish ponds at Mangla;

• collected information on the materials available for the preparation of fish feed;

• prepared a preliminary outline of a practical manual for aquaculture, under local conditions.

4. OBSERVATIONS

Visit to Fish Hatchery and Nursing Unit, Mangla.

4.1 Construction of a pond outlet - monk

In view of the practical problem in draining a pond, the local management had agreed to construct a pond outlet in the form of monk as suggested by the Consultant, and the construction work was initiated on the last day of the Consultant's first visit (see Working Document 4: Section 4.2). During this current visit, it was observed that the work was only half completed. This work must be finished and the same type of monk should be constructed in each pond. Attention needs to be given to constructing monks of a size that is appropriate to the size of the pond they drain.

4.2 Condition of broodfish

During the previous consultancy period, a number of broodfish of rohu, mori and thaila were procured from a private farmer (see Working Document 4: Section 4.5) for breeding purpose. Along with these ripe broodfish, a few common carp as well as silver carp were also stocked for use in the next breeding season of 1988. When the Consultant arrived, the local staff reported a heavy infection of the external parasite Lernea which has caused some fishes to die. An examination confirmed the heavy infection. The broodfish were in poor condition and had suffered a great loss of body weight. The poor condition of the broodstock after only 3 months indicates an extremely low level of management and little attention to feeding or fertilising. This has occurred despite the recommendations made to the staff during the Consultant's last visit.

Considering the seriousness of the infection, the Consultant immediately demonstrated the salt bath treatment (in absence of effective insecticide) in a circular tank (Chinese-type spawning tank) with 21 broodfish. The external parasites dropped from broodfish within a period of 10–15 minutes. Each broodfish was further treated with Acraflavin solution to prevent any fungal or bacterial infection of the wounds. It was recommended to treat all the broodfish in the same way as early as possible. To kill the eggs as well as adult parasites in the pond, it was further recommended to drain the pond water, treat the pond with a high dose of lime and keep it dry under the sun for a few weeks. If these recommendations are ignored, it may jeopardize the breeding work in the forthcoming season.

The Consultant has requested, as an emergency measure, a small supply of essential chemicals (i.e. Malachite green, Acraflavin, Diptrex) to be bought with project funds.

4.3 Fingerling production of previous visit

Inspite of various difficulties, the Consultant was able to produce hatchlings of rohu by induced breeding during the previous consultancy mission. These hatchlings were stocked in three nursery ponds (as reported in Working Document 4). The nursery ponds were covered with old gillnetting to prevent bird predation. However, frog infestation was not prevented. Out of the three ponds, two ponds have shown a considerable growth of fingerlings of 8–10 cm size in a period of three months, while the third pond gave no satisfactory result. This unsatisfactory result was almost certainly due to the poor fish handling techniques observed at the stocking of the pond and again reflects on the low level of staff training. The local staff have conservatively estimated that 50 000 – 70 000 fingerlings have survived. The fingerlings were observed to be healthy and found in good condition. However, for better results the fertilization of the ponds need to be carried out strictly to a scheduled programme with good quality organic manure.

5. PLANNING OF A HATCHERY

5.1 Capacity

Present fish production from the various WAPDA controlled reservoirs is maintained only by a natural recruitment. Therefore, to increase the fish production from these reservoirs a stocking programme must be established and hatcheries constructed to supply the required number of fingerlings. At present there is insufficient information available to define precisely the numbers, species or sizes of fingerlings needed. Therefore, as a guide to hatchery capacity, a stocking rate of 100 advanced (8–10 cm) fingerlings/ha has been assumed at full water level. This stocking rate will require about 1 million, 2.5 million and 2.6 million fingerlings for Hub, Tarbala and Mangla reservoirs respectively. When computed at low water level, the stocking density rises to 285 fingerlings/ha in Tarbela and 654 fingerlings/ha in Mangla reservoir. These stocking levels may be modified on the evaluation of future monitoring of the fisheries and limnological conditions. It is recommended to install hatchery facilities capable of expansion to 5 million fingerlings/year at each hatchery, at full level of operation.

5.2 Biological considerations

In designing the proposed hatchery and pond complexes, the following biological considerations have been taken into account:

1. Selection of fish species

   1. Common carp
   2. Major carps - Rohu, Mori and Thaila

   3. Chinese carps - Grass carp, Silver carp and Bighead carp

2. Spawning period - 28 weeks

3. Status of broodfish

4. Induced breeding

5. Pond requirement to produce 1 million fingerlings

5.3 Management considerations

Each hatchery complex should be equipped with alternative systems for spawning and incubation to guard against the failure of a single system. In addition, the requirement for good quality water (clean and silt proof) demands a reserve of at least 4–6 hours duration.

Considering the above factors, the Aquaculture Engineer Consultant has developed a design for a hatchery and fish farm with a capacity of 5 million advanced fingerlings. This design was presented at a formal meeting held under the Chairmanship of the Chief Engineer, Designing Department of WAPDA.

At the meeting, biological as well as engineering aspects were thoroughly discussed and were accepted. The details of design and guidelines for its operation will be reported in the Aquaculture Consultant's report.

6. CAGE FISH CULTURE

6.1 Potential for cage culture

The possibility of launching pilot-scale cage fish culture at certain pockets of Tarbela (Khalabat), Mangla (Jari) and Rawal reservoirs was discussed in Working Document No. 4. The Consultant Aquaculturist made a special request to the Limnology Consultant to give due importance in observing the availability and seasonal fluctuation of the planktons in these water bodies as these limnological data will help to produce firm guidelines in selecting fish species appropriate to the available natural food and identifying the scale of cage fish production.

To date the limnological data shows the presence of a large number of phyto- and zooplankton in the water bodies of Khalabat pocket of Tarbela, Jari, Khad and Poonch pockets of Mangla and also in the Rawal reservoir. However, at this stage it is too early to make a definite selection of fish species suitable for cage culture.

The cage may be of any dimension but considering ease of handling a rectangular production cage of 50–80 m³ is suggested. To prevent the escape of fish, the opening of the cage should have a provision for closing after stocking. The mesh size of a production cage depends on the fingerling size as well as water quality of the reservoir. Generally, the preferred mesh size for a production cage is 2–3 cm (stretched) to allow a good circulation of water. For carp culture, the cage should float on the water surface supported by a wooden frame, bamboo or stylofoam, while prefabricated cement slabs or stones are used as anchors for positioning the cages. The type of fish and its stocking density depends on the availability of natural feed within the impoundment and duration of the growth period. Keeping in view the high fluctuation of water level, the cage should be of a free-floating type.

The Consultant made an attempt to identify local suppliers or manufacturers of net materials suitable for cage construction, but failed to find a source of an appropriate thickness of twine. In the old market of Lahore, there are two dealers who handle only gill net materials. One of the scientific equipment dealers agreed to procure nylon twine of appropriate size for making nets for cages and also promised to make serious effort to prepare an appropriate net under the Consultant's supervision. However, he failed to make good these promises during the period of the Consultant's visit.

7. SUPPLEMENTARY FEEDING

7.1 Availability of fish feed

The fish culture activity under WAPDA is confined to two small hatchery units at Mangla and Tarbela with a total pond surface of 0.51 ha and 0.45 ha respectively. At present, the requirement for supplementary feed in these two units is negligible.

The following feed materials are available:

1. Cereals by-products

   1. Rice bran
   2. Rice polishing
   3. Wheat bran
   4. Maize gluten

   5. Soyabean or other legume

2. Oil by-products

   1. Soyabean cake
   2. Mustard cake
   3. Sunflower cake
   4. Cotton seed cake
   5. Rape seed cake

   6. Groundnut cake

3. Meat

   1. Meat meals
   2. Blood meal
   3. Bone meal

   4. Fish meal

4. Molasses

   The Consultant was only able to survey one market. The product prices at this market are given in Appendix A.

The growing need of supplementary feed for fish culture may create competition for raw materials with other activities, e.g. poultry industry and cattle farming.

In preparing supplementary feed for fish with available ingredients attention should be paid to the following points:

1. type and quality of feed should be suitable to the type of fish culture;

2. availability of the ingredients in quantity as well as quality must be guaranteed;

3. the cost of the compounded feed must be economic in terms of production. As opposed to the development of compounded feeds, the Consultant gives higher priority to the proper fertilization of the fish ponds and feeding plant materials to grass carp to accelerate the maximum growth of plankton, to ensure optimum growth of fry and fingerlings and the good health of the broodfish.

Supplementary feeding in fish culture has not been widely practiced in Pakistan, so the fish feed industry has yet to develop. However, the operation of the proposed hatcheries and fish farms will demand a considerable quantity of supplementary feed for which the ingredients can be procured locally and the fish feed prepared manually.

In addition, to meet the demand for organic manure, fish culture needs to be integrated with livestock raising, agriculture as well as horticulture.

7.2 Feeding recommendations and techniques

7.2.1 Hatchlings

After hatching, the hatchling starts to exhibit “candling” movement and starts absorbing its yolk sac. Before the yolk sac is absorbed, the hatchling must be fed to make them aware of the availability of food. At this stage, if the hatchlings fail to get food, even for a couple of hours, there may be high losses. Therefore, attention should be given to feeding the hatchlings a few hours before the yolk sac is absorbed.

In addition to microscopic live food, protein rich chicken egg is a good supplementary food for hatchlings for the first 7–10 days. To prepare this supplementary food, an egg, one big sized glass, a spoon and hot water are required. The white albumen and yolk portion of egg is dropped in the glass with hot water. The egg is stirred with the spoon quickly to make an homogenous solution. Adding more warm water the homogenous solution is diluted to about half a litre. Once it cools down, it is ready to feed to the hatchlings in the incubator or happa. The hatchling are fed by dripping the prepared feed with the water. During the feeding period, water circulation or use of sprays should be stopped (but should be started again immediately after feeding). For the first few days (2–4 days) the hatchlings should be fed every two to four hours. Unused egg solution can be stored for a day in a refrigerator.

7.2.2 Fry

To increase the survival rate of the fry in a nursery pond, more emphasis needs to be given to fertilization to increase the growth of natural food (plankton). Besides the natural feed, supplementary feed needs to be changed gradually from semi-fluid to solid form. For the first few days thick soyabean milk should be broadcast several times a day along the shore line of the nursery pond.

To develop a habit for solid feed, a supplementary feed should be prepared with powder of soyabean (about 90%) and fish meal (about 8%) with wheat flour (about 2%). The soyabean powder should be stirred with boiling water to destroy trypsin. Fish meal powder and wheat flour should be poured and stirred into the semi-fluid soyabean suspension until the feed is the consistency of a soft paste. If soyabean is not available or uneconomic, it can be replaced with other beans (e.g. white bean). Prepared feed should be placed in a hanging tray at one or more places (preferably near corners) over the nursery pond. By using a hanging tray, the waste of feed is minimized and it is easy to observe the growing fries. The fries grow to 4–6 cm total length in 3–4 weeks.

7.2.3 Advance fingerlings, growing fish and broodfish

In addition to the natural food made available in the pond by proper fertilization, supplementary feeding can accelerate the growth of advance fingerling, growing fish and the gonadal development of broodfish. The ingredients listed below are available on the local market. To minimize the wastage of such supplementary feed the Consultant strongly suggests to use a binder (Basfin product of BASF is available). The growth of fish should be checked periodically (preferably every fortnight) and the supplementary feed should be provided at the rate of 1–2% of body weight stocked for advance fingerlings or growing fish, while 2–3% of the body weight of broodfish.

1. Feed ingredients for advance fingerling and growth fish:

2. Food for broodfish:

7.3 Preparation of preliminary manual on certain aspects of aquaculture

In addition to the terms of reference described under the project document, the Consultant was asked to prepare an aquaculture instruction manual on routine running of Mangla and Tarbela hatcheries for specially carp seed/fry/fingerling production purposes, maintenance of healthy broodstock, water quality and quantity, fish feed, maintenance of hatchery/fish farm equipment, etc., during this mission.

As the Consultant's field work in this country was for a too short period (few days at Tarbela and about one month at Mangla) to be acquainted with all the activities under local conditions, the Consultant made an attempt to collect information and data from all possible sources. But only limited information could be made available as a proper feedback system or interaction with local data and experience does not exist in the Department. In these circumstances, the Consultant could make an attempt to prepare a preliminary manual in certain aspects of aquaculture. However, due to time constraints, he could not complete this work, but hopes to finish it within a few weeks time. The synopsis of the general manual is attached with this report as Appendix B.

8. ISSUES

8.1 Fingerling supply to small reservoirs

The fingerling needs of the small reservoirs (e.g. Khanpur, Rawal and Simly) do not justify the establishment of a full-scale breeding facility. The WAPDA controlled reservoir at Khanpur can readily be supplied from the proposed Mangla hatchery. Growing ponds should be established at this reservoir to raise fish to advanced fingerling size. Rawal and Simly (not WAPDA controlled reservoirs) have access to ample supplies of seed fish from the Punjab Fisheries Department hatchery at Rawalpindi.

8.2 Pilot-scale cove fish culture

Most of the major reservoirs have many coves with gentle slope. During the low water level of the reservoirs these coves get dry and gradually innundate with the filling of the reservoirs. These areas could be utilized either for the production of large fingerlings or for fish culture by blocking the drawdown areas of a cove from the main water body using nets at one or two levels within the cove. In the case of fingerling production, the cove is fenced with a smaller mesh (1–1.5 cm) net, while for fish production larger mesh (2–2.5 cm) net prior to the filling of the impoundment. This method has been realized recently as a good means to increase the size of fingerlings for greater stocking success on release to the main water body.

8.3 Fish nutrition

So far formulation of an appropriate fish feed has never been considered important as fish culture activities under WAPDA administration was in an initial stage of development. However, future developments in these reservoirs (establishment of hatchery, fish farm and also possibility of adopting different method of aquaculture) will considerably increase the demand for fish feed. Such fish feed must be prepared with locally available ingredients. Consideration should be given to the establishment of a fish nutrition cell in future programmes to cater for the problem of fish nutrition.

ACKNOWLEDGEMENTS

The Consultant wishes to express his sincere thanks to Mr. I. U. Naik, Director, Department of Fisheries, WAPDA, Mr. A. Mehboob, Assistant Director Fisheries Department of Fisheries WAPDA Headquarters, Mr. Sadaqquat Hussain, Deputy Director of Fisheries and Mr. Mirza, Assistant Director of Fisheries, Mangla, for their cooperation and assistance in carrying out the work.

APPENDIX A

VARIATION OF PRICE OF FEED INGREDIENTS LAHORE-AKBAR MANDI

APPENDIX B

PRELIMINARY MANUAL ON CERTAIN ASPECTS OF AQUACULTURE

Synopsis

1. Introduction

2. Aim and objective

3. Maintenance of healthy brood stock

   3.1 Future brood stock
   3.2 Donor fish for pituitary gland
   3.3 Brood fish
   3.4 Fertilization
   3.5 Feeding.

4. Hatchery and breeding

   4.1 Hatchery facility
   4.2 Breeding
   4.2.1 Semi-induced breeding
   4.2.2 Induced breeding

5. Fingerling production

   5.1 Nursing - hatchling to fry
   5.2 Rearing - fry to fingerling
   5.3 Fertilization

6. Parasites, diseases and their remedies.