T E C H N I C A L    C O O P E R A T I O N    P R O G R A M M E

TCP/PNG/4503 (A) Field Document 2 April 1986

PAPUA NEW GUINEA

A report prepared for the
Re-establishment of carp fishing project

based on the work of

J. Kövári
Aquaculture Engineer

This report was prepared during the course of the project identified on the title page. The conclusions and recommendations given in the report are those considered appropriate at the time of its preparation. They may be modified in the light of further knowledge gained at subsequent stages of the project.

The designations employed and the presentation of the material in this document do not imply the expression of any opinion whatsoever on the part of the United Nations or the Food and Agriculture Organization of the United Nations concerning the legal of constitutional status of any country, territory or sea area, or concerning the delimitation of frontiers.

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome, 1986

Hyperlinks to non-FAO Internet sites do not imply any official endorsement of or responsibility for the opinions, ideas, data or products presented at these locations, or guarantee the validity of the information provided. The sole purpose of links to non-FAO sites is to indicate further information available on related topics.

This electronic document has been scanned using optical character recognition (OCR) software. FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.

TABLE OF CONTENTS

1. INTRODUCTION AND TERMS OF REFERENCE

2. BACKGROUND INFORMATION

3. HIGHLANDS AQUACULTURE DEVELOPMENT CENTRE AIYURA

3.1 Location

3.2 Topography

3.3 Soil

3.4 Climate

3.4.1 Temperature (1956–70)

3.4.2 Sunshine (1956–70)

3.4.3 Rainfall

3.4.4 Evaporation

3.4.5 Humidity (1956–70)

4. DESIGN OF REHABILITATION AND EXPANSION OF HAQDECA

4.1 General Outline Layout Plan

4.2 Water Requirements for the Fish Ponds and the Reservoir

4.2.1 Pond filling

4.2.2 Water losses

4.2.3 Water inflow to the ponds

4.2.4 Summary

4.3 Renovation of Existing Ponds

4.4 Improvement of Existing Hatchery

5. ESTIMATED COST OF CONSTRUCTION

6. CONCLUSIONS AND RECOMMENDATIONS

LIST OF FIGURES

1. Highlands Aquaculture Development Centre Aiyura

LIST OF DRAWINGS

1. Contour map

2. General outline layout plan

3. Typical cross sections

4. Plan of hatchery building

1. INTRODUCTION AND TERMS OF REFERENCE

The Government of Papua New Guinea, assisted by the Food and Agriculture Organization of the United Nations under its Technical Cooperation Programme, is engaged in the Re-establishment of carp fishing project (TCP/PNG/4503 (A)) whose main objective is to advise on the re-establishment of carp fishing facilities in the Highlands and on a training programme for management of the fish production.

As part of the project operations, FAO assigned Mr J. Kövári as aquaculture engineer from 10 November to 8 December 1935 with the following terms of reference:

During a period of 4 man-months to prepare plans and supervise the construction work, and specifically:

1. design an expansion to the present hatchery

2. design an integrated livestock cum-fish pond

3. rehabilitate the existing ponds and hatchery

4. initiate construction of hatchery expansion and the new pond.

Due to the shortening of the consultancy to one month, the terms of reference and site programme were modified with the agreement of Mr Petrous Sagom, Director, Highlands Aquaculture Development Centre, Aiyura (HAQDECA), Department of Primary Industry (DPI), and the following tasks were carried out by the author in Aiyura:

1. topographic survey of the existing ponds and the area of the proposed expansion to the existing ponds

2. topographic survey of the existing hatchery

3. design of the outline, general layout of the existing and proposed new ponds

4. design of the typical dike sections in the ponds

5. design of the outline plan of the hatchery for its improvement

6. estimated cost of construction works.

2. BACKGROUND INFORMATION

Common carp aquaculture is the only inland aquaculture taking place in the Highlands of Papua New Guinea. At present, the great majority of fish consumed in the Highlands are canned or frozen products mostly imported from Australia, Japan and New Zealand. There is therefore a great need for an improved supply of fresh fish.

The DPI, Fisheries Division initiated the fish culture programme soon after its formation in 1954. Several fish ponds were constructed by DPI. Four areas where those ponds were established include Kanudi and Bomana in the Central Province, Aiyura in the Eastern Highlands Province and Dobel in the Western Highlands Province. With the exception of the Aiyura ponds, the Dobel, Kanudi and Bomana ponds have now ceased to operate. Until now, carp aquaculture has been mostly carried out by mission schools and some private enterprises. Carp fingerlings have been supplied to them from HAQDECA.

However, this Centre has not been able to satisfy the demand. There is a need to re-activate and nationalize the hatchery, including reconstruction of the existing ponds and build new ponds. Also better fish feed is needed and a training programme to safeguard good management. This should also lead to an enhancement of the supply of fingerlings for distribution, and to an improvement of fish production in the Highlands.

3. HIGHLANDS AQUACULTURE DEVELOPMENT CENTRE AIYURA

3.1 LOCATION

The centre is situated about 11 km southsoutheast of Kainantu, to which it is connected by road. Kainantu itself is 2 hours by road from Goroka and 4 hours from Lae. The fish ponds of the centre are located along the airstrips. Airstrip elevation is about 1 620 m (see Fig. 1).

3.2 TOPOGRAPHY

According to the topographic survey carried out, the contour map including the existing ponds is shown in Drawing No. 1. The local temporary Bench Mark (TBM) with an elevation of 100 m is the top of the tower of the outlet structure in the existing pond Pl.

The existing hatchery building was surveyed and its plan is shown in Drawing No. 4.

3.3 SOIL

Below the black topsoil, at a depth of 40–50 cm clay was found at the pond site. Its colour ranges from yellow to grey. The structure is strong. The consistency of the clay is extremely hard when dry and very sticky when wet. The depth of the water table is not known at the site. The soils investigated are suitable for the construction of the ponds.

3.4 CLIMATE

Although the local climate is strongly related to topography, the major climatic controls are influenced by seasonal latitudinal movements of two air masses separated by a low pressure belt, the Intertropical Convergence Zone (ITCZ). Northwest winds prevail from late December through to mid-April when the ITCZ is situated over, or to the south of Papua New Guinea. Because the heaviest and most frequent rainfalls are associated with these winds they are frequently called monsoons. Between May and October, when the ITCZ lies to the north of Papua New Guinea it causes dominantly southeasterly winds, also known as trade winds, which blow with great regularity over the Coral Sea. Except in areas affected by strong orographical influences these trade winds do not produce frequent, heavy rainfalls. The short transitional periods between the two seasons are characterized by flukey winds called “doldrums”. These periods occur during late October and November and again during late April and May. In highland areas the seasonality in rainfall is still present, particularly in the east, but is much less marked due to local variations mainly related to topography.

Data were derived from the Aiyura Station No. 200003. The elevation of the station is 1 670 m above sea level.

3.4.1 Temperature (1956–70)

The mean monthly temperature is between 17.4 and 19.4°C with extremes ranging from -0.6° to 30.8°C. Mean annual temperature is 18.6°C. Average monthly temperature figures are as follows:

3.4.2 Sunshine (1956–70)

The mean daily sunshine (hours) per month and annual total are as follows:

3.4.3 Rainfall

According to the records for the 1937–80 period, the mean annual rainfall is 2 101 mm. Of this, 47 percent falls between December and May. Rainfall figures are as follows:

3.4.4 Evaporation

Mean monthly and annual estimates of evaporation from a US class A Pan are as follows:

3.4.5 Humidity (1956–70)

Figures of mean monthly 09.00 and 15.00 h relative humidity (%) and average index of relative humidity are as follows:

4. DESIGN OF REHABILITATION AND EXPANSION OF HAQDECA

4.1 GENERAL OUTLINE LAYOUT PLAN

The general outline layout plan (Drawing No. 2) includes a reservoir of 0.45 ha and four existing ponds of 1.12 ha and 43 new ponds having a water surface area of 4.25 ha of various sizes (Table 1) and the area reserved for the buildings (new hatchery, laboratories, stores, staff quarters, training centre with hostel and classroom, etc.) will be built in the future.

The water stored in the reservoir will be used for both the new hatchery through a filter system needed to provide a higher survival rate of hatchlings in the hatchery and the ponds P20–P45 when there is not sufficient water flow in the feeder canal.

The average water depth in the reservoir and the new ponds would be 1.50 m and 1.20 m respectively. The height of the dikes would provide 50 cm freeboard above the designed water levels of the reservoir and ponds. The width of dike crests would be 2.0 m, and 4.5 m for that of the road dike. The dikes will have interior slopes of 1:2 and of 1:1.5 outside the ponds and drainage canals. Typical cross sections of the dikes are shown in Drawing No. 3. To avoid erosions in the water supply, it is recommended that canals be lined with 15 cm thick concreted gravel and their slopes should be 1:1. All ponds would be provided with inlet and outlet structures. All inlets would be PVC pipe with 100 mm diameter for experimental and nursery ponds and 150 mm diameter for fingerling ponds and 200 mm diameter for broodstock and rearing ponds respectively. Turndown PVC pipe outlets with 150 mm diameter are recommended for the expe- rimental, nursery and fingerling ponds and reinforced concrete structures for the brood stock ponds and reservoir with 30 cm and 40 cm diameter concrete pipes respectively, similar to the outlet structures in the existing ponds P1–P4.

4.2 WATER REQUIREMENTS FOR THE FISH PONDS AND THE RESERVOIR

4.2.1 Pond Filling

The yearly amount of water required for filling the existing and proposed ponds as well as the reservoir is as follows:

4.2.2 Water Losses

As indicated in paragraph 3.4.4, the mean annual evaporation in Aiyura is 1 581 mm taking into account that the soils found at the site have high a clay content, and, therefore, the seepage can be assumed to be 2–3 mm/day. Hence the total annual water losses in the ponds and the reservoir are:

(i) From evaporation

Where:

A = total area of the ponds and reservoir = 5.82 ha = 58 200 m²

E = mean annual evaporation = 1.581 m

O_D = assumed yearly operational days = 300 days

(ii) From seepage

WL_s = A × s × O_D m³

where:

A = total area of the ponds and reservoir = 58 200 m²

s = daily seepage = 0.0025 m/day

WL_s = 58 200 × 0.0025 × 300 = 43 650 m³, say 44 000 m³

Total water losses: WL_e + WL_s = 76 000 + 44 000 = 120 000 m³

4.2.3 Water Inflow to the Ponds

The mean annual runoff is calculated applying the equation below:

R = A × Ra × C m³

where:

A = water catchment area of the water supply canal in m²

Ra = mean annual rainfall in m

C = runoff coefficient

Using the above equation with:

Ca = 0.5 km² = 500 000 m²

Ra = 2 101 mm = 2.10 m

C = 0.40¹ (woodland)

Hence:

R = 500 000 × 2.10 × 0.40 = 420 000 m³

¹ ADCP/REP/94/21, Hydrological Formula, Table 1, page 171

4.2.4 Summary

A. Water requirements for operation of the ponds and reservoir:

It appears that the water requirements may be supplied from the water catchment area of the water supply canal in average years.

4.3 RENOVATION OF EXISTING PONDS

The existing four ponds were originally constructed some 30 years ago, hence, all of them have been silted up with 20–40 cm thick silt. All the ponds can be completely drained. As the pond bottom P1 around the outlet was 40 cm deeper than the floor level of its outlet an additional PVC outlet pipe with 15 cm diameter was built to drain the pond properly.

The inner slopes of the ponds are eroded because the dikes were mostly constructed of the top soils excavated from the ponds sites and no proper maintenance has been carried out since their construction. The different slope protections used against erosion have not been applied appropriately.

The following works must be carried out in the existing ponds P1–P4 during their renovation:

1. After draining and drying-up their bottoms they have to be desilted. The silt excavated from the pond bottoms may be utilized either for fertilization of the horticultural projects adjacent to the fish farm, or for strengthening the outer slopes of the dikes.

2. The inner slopes of the dikes should be formed with a slope of 1:2. The earth used for sloping the dikes should be thoroughly compacted. Their Proctor density should be minimum 85%. The materials used for dike sloping should be selected clay from the site of the new ponds. The existing slope protection materials may also be used for the new slopes.

3. The slopes in the ponds to the doorway of the existing duck houses should be 1:3. These slopes should be protected with concreted gravel.

4.4 IMPROVEMENT OF EXISTING HATCHERY

The hatchery building was built in the centre of Highlands Agricultural Experimental Station, Aiyura 1.5 km from the fish ponds. The plan of the hatchery building for its improvement is shown in Drawing No. 4. According to this plan the following improvements are recommended:

1. The present main water supply pipeline (diameter ¾ inch) has to be changed with one of 2 inch diameter to ensure enough water flow for the proper operation of the hatchery.

2. Two multipurpose concrete tanks used for holding the spawners, egg hatching and larval nursing should be built in the indoor hatchery building. The proposed tanks can be used for common and Chinese carps as well as Indian major carps.

3. The section of 10 × 8 cm of the existing drain should be enlarged to 20 × 20 cm to ensure adequate drainage of the tanks.

4. The existing four fibreglass tanks may be used for larval nursing and experimental works.

5. To ensure a more successful spawning and a higher survival rate of the hatchlings, 0.5 HP air blower with an output capacity of 75 m³/h at 0.3 kg/cm² should be provided to the hatchery.

The proposed timetable for hatchling production in the hatchery is given below:

Operation time in the hatchery for one batch of hatchlings

T_O = T_AS + T_1B + T_H + T_AYS + T_F = 1 + 1 + 1 + 3 + 2 = 8 days

Time needed in the hatchery for spawners for the duration of one batch of hatchlings

T_S = T_AS + T_1B = 1 + 1 = 2 days

Interval between two batches of hatchlings

T = T_o - T_s = 8 - 2 = 6 days

Considering two months (60 days) for peak spawning season, the number of batches of hatchlings may be as follows:

Hatchling production of the hatchery with two multipurpose tanks in each batch is given below:

Volume of one multipurpose concrete tank

V = 1.20 × 3.30 × 0.95 = 3.70 m³

Spawner holding capacity of the tank = 15 kg/m³

Total number of eggs provided per each batch

Ne_B = S_w × M × B × F = 50 × 0.40 × 0.80 × 100 000 = 1 600 000

where:

Maximum loading capacity of one hatching basket = 250 000

Number of eggs placed into each hatching basket

Number of hatchlings from 10 hatching baskets

where:

F_e = fertilization of eggs = 85%

S = survival rate of hatchlings = 60%

5. ESTIMATED COST OF CONSTRUCTION

Footnotes:

¹ Cutting and removing vegetation in 60% of total area, 56 400 m² at K 0.05/m²

² Desilting the existing ponds P1–P4 with haul of 500 m and disposal of the excavated silt around various horticultural projects and on the top of the new dikes for turfing 3 360m ³ at K 1.0/m³

³ Removing and storing the existing bank protections on the top of the dikes and placing them on the renovated slopes of the ponds P1–P4, 700 m² at K 1.5/m²; bank protections to use 30 cm thick dry gravel pitching 600 m² at K 1.2/m²

⁴ Excavation, 200 m transportation, compaction and forming slopes of 1:2 in the ponds P1–P4, 1 900 m³ at K 1.5/m³

⁵ Excavation of new ponds, reservoir and drainage canals, 24 000 m³ at K 1.5/m³

⁶ 30 cm thick dry gravel pitching 7 400 m², at K 1.2/m²

⁷ Levelling pond bottoms, 36 000 m² at K 0.05/m²; turfing dikes 12 000 m² at K 0.10/m²; plantation trees at K 300; clearance entire area at K 350

⁸ 30 cm thick gravelled surface, 2.5 m wide, 3 800 m² at K 1.2/m²

⁹ Water supply canals lined with 15 cm concreted gravel, 1 350 m at K 5.0/m, 22 PVC pipe inlet with 100 mm diameter, at K 20/inlet; 15 PVC pipe inlets with 150 mm diameter, at K 25/inlet; 12 PVC pipe inlets with 200 mm diameter, at K 35/inlet; one intake structure at K 1 200

¹⁰ 37 PVC outlets with 150 mm diameter, at K 100/inlet, seven concrete outlets with 45 cm diameter, RCC pipe at K 600/outlet; six culverts with 45 cm diameter, RCC pipe atK 350/culvert

¹¹ Two multipurpose concrete tanks with drainage canals, at K 400/tank; one filter tank at K 500/filter tank; 100 m water supply pipeline (2 inch diameter) at K 6/m.

6. CONCLUSIONS AND RECOMMENDATIONS

Considering the high potential of aquaculture in Papua New Guinea and the increasing interest in carp culture in various provinces (Eastern Highlands Province, Western Highlands Province, Chimbu, etc.), the following recommendations for the aquaculture development in Papua New Guinea are put forward:

• HAQDECA may be developed to an aquaculture training centre for extension workers and fish farmers;

• HAQDECA can supply fingerlings needed for stocking the existing rural fish ponds and fish ponds which will be built in the Eastern Highlands Province;

• For the aquaculture development in Papua New Guinea a detailed survey should be carried out to determine the local aquaculture potential in each province. This survey should cover the location, size, water supply and drainage possibility, and access to fish ponds.

The preparation of detailed plans and commencement of construction works will require three man/months.

Scale: 1:100 000

Fig. 1 Highlands Aquaculture Development Centre Aiyura. Location map

1. Contour map

2. General outline layout plan

3. Typical cross sections

4. Plan of hatchery building