With the approval of the Director-General of the Division of Fisheries, Ministry of Agriculture and Land Reform of the Government of Malaysia, two of the authors (W.L. Chan and J. Ho) were sent by the Director of the Department of Agriculture and Fisheries, Hong Kong, at the request of the Food and Agriculture Organization (FAO) and the United Nations Development Programme (UNDP) through the South China Sea Fisheries Development and Coordinating Programme (SCSP) to make an assessment of the feasibility of initiating a marine fish culture pilot project at two pre-selected areas at Pulau Perhentian Besar and Kuala Setiu Lagoon off and along the east coast of Peninsular Malaysia, respectively.
Their terms of reference are:
A. W.L. Chan
To make a general assessment of the initiation of cage culture of marine fishes in Pulau Perhentian Besar and Kuala Setiu Lagoon;
To prepare a detailed programme for the first year's operation;
To list essential supplies and equipment;
To recommend necessary expatriate expertise and counterpart personnel; and
To submit a report on these.
B. J. Ho
To provide practical expertise for initiating and demonstrating fish seed collection and fish culture in cage.
Their travel and work programmes are summarized in APPENDIX A. Site investigations were mainly carried out in the period from 31 July to 8 August 1977 prior to the departure of Chan from Kuala Besut. In the remaining part of the stay of Ho, preparation of culture trials and a survey of fish seedlings were carried out.
Together with the co-authors from the Malaysian fisheries authority, they formed the investigatory team responsible for these undertakings. The other author, Mr. H.L. Cook, previously of the SCSP and involved in the initial preparatory phases of this Project, also participated for a period prior to the departure of Chan.
Arising from the findings of the first part of the programme (APPENDIX A), the proximity of the selected site in the lagoon to the outflows of adjacent mangrove streams was considered a possible constraint to the future development potential of the selected and other future sites in the lagoon. Three of the authors (Chan, Lam and Low), therefore, conducted another hydrographic survey towards the latter part of November 1977 (APPENDIX B) when the annual peak of rainfall for 1976 was recorded at Kuala Trengganu (Table 3). This period was selected on the assumption that increased freshwater runoffs from the land and riverine discharge might incur a different ecological setting in the lagoon environment.
This document, therefore, serves to report on the results of these investigations with the object of identifying development potential of the two pre-selected areas and recommending actions necessary for the attainment of the objectives of the Project.
Being a recent introduction, marine fish culture in the South China Sea region is still in an early phase of development. The design of a practical, workable set of culture management techniques, therefore, becomes the most difficult issue especially in view of the diverse variety of fish species being utilized under different ecological settings, and indeed our inadequate understanding of the biology and behaviour of the species involved. Deficiencies in the existing marine fish culture “systems” can clearly be realized when compared with some of the well-established inland fish culture systems. The considerably higher yield rate in marine fish culture is a separate issue, essentially one taking advantage of natural forces in oxygen budget requirements, and must not subjectively emphasized to obscure the circumstances.
In the culture of marine fish, one actually confines dense stocks of “wild” carnivorous and omnivorous fishes in “selected” bodies of water. Confinement often creates ecological stresses on the stock, deprives the species of its optimal conditions for survival, and accelerates the spreading of diseases. Under the circumstances, adverse effects on the confined stocks ranging from mass kills to stunted growth, have already been observed.
Apart from these facts, a number of human factors further complicates the design of culture management techniques. First and foremost is the strongly biased “criterion” in the selection of culture sites, one solely and entirely based on the physical convenience on the part of the operators. Under the circumstance, the suitability of the environment to the survival of the species to be cultured, and any conflicts with other fishery and maritime activities are, as often as not, ignored. Second is the complete disregard of the potential adverse effects of nearby pollution sources on the water quality of the “preferred” sites. Third is concerned with a lack of control of culture and associated activities which often create a direct source of pollution, and which in the course of time, render the culture site unsuitable for further utilization.
A much more subtle and difficult human issue is perhaps the problem of poaching and sabotage. This is, however, essentially a legal problem on one hand, and a lack of legal recognition and therefore protection of the rights of the owner/operator to his fish and culture facilities on the other.
Another area of problems is concerned with a lack of emphasis on the infrastructure of this new form of fish production, especially its possible interrelationships and interactions with other sectors of the fishery, the process of product disposal, and existing and potential markets. In these considerations, one has to assume by necessity, that the pilot culture trials would reveal favourable results in support of medium- and long-term development. One has also to take into account of the existing socio-economic setting, availability and cost of the essential materials, and other associated problems concerned with the benefits of the future operators.
The work programme has taken into consideration the need for information in understanding these problems. Due to the very much limited time available to the team, the information acquired is not by any means adequate for the purpose of resolving the principal problems inherent in the two areas studied. Wherever appropriate, such deficiencies are noted in the sections that follow.
The areas investigated include Pulau Perhentian Besar and the estuary and northern stretch of the Kuala Setiu Lagoon, with special emphasis on the hydrographic conditions at the time, as well as the faunastic and other relevant features of these areas. Early morning visits to the fish landing sites at Kuala Besut were made to provide a general understanding of the capture fisheries and the quality and value of the “trash” taxon, which would presumably serve as the main source of fish feed in the pilot culture trials.
Hydrographic sampling was carried out, as far as possible, during slack, ebb and flood tides in each of the two areas. In the case of the lagoon, it was necessary to conduct night sampling in view of the seemingly high productivity and apparently vigorous mixing of sea and riverine waters as shown on the first visit by the contrasting colours between adjacent “bodies” of water. This was also essential to detect any direct influence of the mangrove stream waters on the lagoon proper.
Water measurements were made with a dissolved oxygen/temperature meter with a pressure compensated 15 m probe, a portable pH meter, a simple water sampler, and a salinity refractometer. Measurements were made at 0.5 m intervals in the lagoon, and only for surface (0.5 m) and bottom (1 m off) for the island.
Drift bottles were used to give an indication of the pattern of tidal water flow. This was possible in working the island site. Due to the presence of sand and mud bars, it was however, impossible to attempt this information for the lagoon.
Underwater observations for general information and on the nature of the substrate and the fauna in general, have also been made in the island site.
Discussion and consultation were made as frequently as possible with the Team Leader and his staff, and within the team.
The area investigated was the northeastern corner of the inner bay located on the southern shore of the island, for the reason that it is the only significantly large water body well protected from strong weather and sea conditions during the northeast monsoon from October to February.
The seabed of this bay is essentially sandy with a fringing coral reef extending from the beach to 10 m at some points and 20 m at others. At the outer reef, the seabed drops sharply to 10 to 15 m and then further down to about 40 m at the entrance of the bay. The inner part of this reef at various points has been destroyed, so that the seabed is devoid of any living corals and provides easy access to the beach head. The outer part of the reef is still intact composing mainly of staghorn and brain corals.
Underwater observations have shown a typical coral-reef fish fauna comprising a diverse variety of species. In the main, coral reef labrids, scarids, pomacentrids, serranids and lutjanids of small and medium sizes predominate the reef proper, with free swimming coral-reef atherinids, dussumieriids, belonids, carangids and scombrids. At the outer reef where the seabed is sandy, small shoals of large-sized scarids and lutjanids have also been observed. Further observation on the fish fauna in the deeper parts of the bay was impossible in the absence of scuba diving gear.
Hydrographic measurements taken at the five stations located at the northeastern corner of the bay (Fig. 1) have shown a generally uniform water column without any indication of a thermocline or halocline (Tables 1 and 2). Salinity, dissolved oxygen and its percentage saturation, and pH values all suggestive of direct influence of open sea water on both occasions, one at the end of an ebb and the other a flood. The relatively low pH values of 7.70 and 7.85 recorded for Station 1 on 1 August 1977 are difficult to explain. It might have been due to the outflow of freshwater from an adjacent stream, as “streaks” of dead organic matters were observed from the point of outflow. On the other hand, the high surface salinity value under the same circumstance contradicts this assumption.
As for any bay or indentation of a shore line, tidal water transport in the bay as shown in Fig.2 and 3 tends to assimilate a circulatory pattern. From the drift tracks, it would appear that tidal waters at 1 m and 5 m and presumably, therefore, the water column tended to move in the same direction and perhaps speed. Towards the end of the ebb on 31 July 1977, the water at the five stations appeared to move in a restricted clockwise direction within a limited area. The dynamics of this ebb is difficult to explain, and in all probability tidal water movement in the whole bay could be rather complicated. On the other hand, however, flood waters according to the drift tracks (Fig. 3) appeared to come in either through the mid-entrance or the western side of the bay. In the former instance, the drift tracks recorded could then be a counter movement; but if this was true the water flow pattern should also be similar for the western shore of the bay. In the latter case, water movement during a flood would simply be a clockwise pattern.
With these limited observations, some broad conclusions in relation to the suitability of the bay for marine fish culture can be drawn.
The fact that the bay is well-oxygenated and directly influenced by open sea waters, indicates that it is pollution-free. Further, the fact that it is well-protected from the strong northeast monsoon is another factor in favour of its potential as a marine fish culture area.
It is therefore recommended that it be a suitable area for the introduction of marine fish culture.
It is, however, necessary to caution that because of the presence of freshwater streams flowing into the bay, the formation of haloclines during minimal and slack tides in the peak rainfall periods is considered a potential risk to the confined fish stocks. When such conditions occur especially coupled with high temperature and low atmospheric pressure, caged fish stocks have elsewhere been recorded to experience mortalities of varying magnitude. The trapping of metabolites, low oxygen transfer between the air and the upper layer of less saline water, the abrupt increase in Biological Oxygen Demand (BOD), and the lack of, or minimal oxygen transfer between the upper (less saline) and the lower (more saline) water layers, have been found to abruptly reduce the percentage saturation of dissolved oxygen and increase ammonia concentration to a letnal level within the cage water. Under such circumstances, the cause of fishkill has been identified as one of asphyxiation. When such a phenomenon takes place direct or indirect vigorous mixing of the water column in the cage should be immediately carried out.
The observations made on the two occasions can only be regarded as being indicative of the general conditions for the month of July bearing in mind also the abnormal dry weather that has prevailed in 1977. Attempts should therefore be made upon the implementation of the pilot culture trials, to monitor the water column for such possibilities.
Another potential cause of fishkill in this bay could be the combination of high temperatures, low atmospheric pressures and minimal tidal flow. The absence of pollution sources in the neighbourhood and the good water conditions suggest that this could be an unlikely event unless and until the whole bay was developed in the absence of any form of control with respect to the activities of the operators.
Being a coral-reef habitat and exposed to periodic strong swell and wave actions, the authors are of the opinion that the bay is more suited to a mixed species culture system using floating cages of greater material strength. This system should be primarily one of the fattening under-sized fishes of species which would otherwise fetch a ready market at a reasonably good value (say, as compared with the target species set in the Project Document).
The species to be utilized should primarily be fast-growing marine fishes of significant average daily weight increment (Table 7).
Snappers:
Lutjanus sanguineus (red snapper)
L. sebae (emperor snapper)
L. johnii (John's snapper)
L. russelli (Russell's snapper)
Groupers:
Epinephelus fuscoguttatus (mottled grouper)
E. bleekeri (Bleeker's grouper)
Promicrops lanceolatus (giant grouper)
Plectropomus spp. (seabasses)
Large-eye breams:
Gymnocranius spp. (large-eye breams)
Sweetlips:
Plectropomus spp. (sweetlips)
Jacks:
Caranx and Carangoides spp. (jacks)
With regard to the three target species, Lates calcarifer (giant sea perch) is unsuitable for the area, while Lutjanus argentimaculatus (mangrove snapper) and Epinephelus tauvina (estuarine grouper) from the lagoon can be utilized at the island site. Although the latter two species have been known to have a high tolerance to wide salinity fluctuations, they have also been found to suffer mortalities in cage culture resulting from abrupt salinity changes especially among the fingerling and early juvenile stages of development. In nature, these early phases of development are normally associated with coastal and estuarine environment, and it would therefore be a risk to transfer the young fish of these species immediately and directly to this island site from the lagoon. With the present day limited knowledge of the biology of these species, it would be a subjective decision to do such transfer without substantial experience and knowledge. It is, therefore, proposed that attempts should be made to transfer these species at, say, 150 g size or greater on a trial basis. Once the techniques are established, further decisions can be made in the utilization of these species at the island site. It is always advisable to work from the known to the unknown.
The source of “fish” for the initial stocking in the beginning of the pilot scheme therefore includes:
150 g or larger individuals of the mangrove snapper and estuarine grouper from the lagoon either directly collected by the project staff or purchased from the fishermen; and
Under-sized fish of the above-listed fast-growing species collected by the fishermen based at the fishing village on the island.
The conditions of the fish for stocking should meet with the following simple requirements:
All scales intact, undamaged to avoid subsequent fungal and bacterial infections often leading subsequently to mortalities and the spreading of the contracted pathogens to the rest of the cultured stock; and
Special standards should be imposed upon the acceptable fish apart from (a), that the snout and the anterior head parts must also be in good normal conditions for the same reasons; and, in addition, discourage the use of gillnets, unsuitable traps and other collecting gear.
The culture method to be adopted for the bay should ideally be the floating net cage type, the design, scale and size of which can be flexible and should primarily be decided by an initial estimate of what should be the desirable margin of net profit.
For the purpose of the pilot culture trials, two 12 m × 12 m bamboo rafts floated on a 44-gallon oil drums for the suspension of 4 5 m × 5 m × 5 m knotless nylon-net cages, are suggested to be used (Fig. 4). These should be moored between Stations 2 and 5 (Fig. 1), and the mooring arrangement is shown in Fig. 5. To reduce the rate of fouling and rusting, the drums should be coated with a layer of “flintkote”.
Plastic containers can be used in place of the oil drums, but in doing so, calculation of the equivalent number of such containers to the suggested number of oil drums for each side (12 m) by simple reference to differences in volume capacity, should be calculated. The selected type of plastic container should be elongate and “squarish” in cross section.
A list of the essential materials for the construction of the proposed 12 m × 12 m raft is given in Table 5. An indication of the expected average life span of item is also given, and this should be taken into consideration in estimating the average annual cost of facility input.
The stocking of each net cage should include only juvenile fish at around 150 g, or approximately 4 to a catty (1 catty = 0.61 kg), at which phase each of the suggested species would tend to be capable of attaining its average maximum daily weight increment, particularly the groupers and snappers. In each cage, the bottom area (25 m2) are assumed to be utilized by grouper(s), and the remaining water column by snapper(s) or the other listed fishes.
On a per-cubic-meter basis, each of the 125 m3 cages could accomodate a final biomass at harvest of 8 to 10 kg/m3 of grouper(s) for the upper half of the cage. This means a rather optimistic suggestion of 500 to 625 kg of grouper(s) and of 187.5 to 312.5 kg of snapper(s), or a total of 687.5 to 937.5 kg per 62.5 m3 cage per year in first annual harvest. These would be the equivalent of 275 to 375 tonnes per hectare of confined sea surface area of annual yield rate.
In terms of stocking density, this means an initial stock of about 550 to 680 live specimens of 150 g grouper(s), and 200 to 340 tails of 150 g snapper(s) are required for each cage. If all the four cages are used, these stock figures will be raised by a factor of 4.
Management of culture operations should be initially simplified to include the following:
Daily operations
One full satiation should be given to the caged fish in the early morning preferably before 9 a.m.
Feeds should comprise of fresh “trash” from fish landing sites. If the fish in the “trash” are small, initially they should be either fed whole and if not possibly cut, but not minced. The crustacean contents in the “trash” are the most desirable items. In the case of shrimps they should be given whole. In case of small crabs, the carapace should be crushed and then also fed whole (Table 4).
Feeding should be done with the hand to avoid wastage and to ensure even chance of feeding irrespective of the kind and size of the fish. The “trash” ready to be fed should be administered by a “throwing” action with the hand at a 45° angle with the sea surface, so that each “throw” tends to “spread” the feeds within as wide an area as possible. This reduces the chance of having two or more pieces of feeds sinking along the same vertical “line” on one hand, and avoids the crowding of the stocked fish within a restricted area on the other. Indirectly these circumstances help to avoid unnecessary physical damage to the stocked fish, and to give each stocked fish an even opportunity to feed.
Feeding should stop as the stocked fish shows any signs of “slowing down” in reacting to the given feeds. At this point, the quantity fed should be about 5% (or more) of the total biomass of the caged fish.
Assuming an average daily weight increment of 2 g/fish, the amount of feeds to be arranged should be contemplated at a monthly increase of 40%.
Any fish showing obvious signs of serious fin rot, external signs of damage or abnormality, and murky appearance to the eye(s) should be dipped out with a soft-netted, shallow dip net and placed into a separate simple floating cage away from the main rafts. Fishes of such conditions should still be fed, but they are prone to suffer eventual mortality or at best to thrive with minimal growth.
Occasional operations
On the occurence of strong southerly winds, observations should be made to assess the ability of the raft in withstanding adverse sea conditions, particularly the incoming swells. A cover net should be rigged up for each of the four cages. If the operator(s) sees the need, an additional anchor should be lowered and attached to each of the outer corners of the rafts.
At times of prolonged minimal or slack tide conditions, especially coupled with heavy rainfall and “uncomfortable” hot weather, the caged fish should be under close observation as frequently as possible. Any signs of increasing turbidity, changes in water “colour”, coupled with the “surfacing” of the confined fish, attempts should be made to vigorously and vertically “stir” the water in and immediately outside the cages. After some time, if the “surfacing” of the fish becomes less obvious, the stirring action can be stopped but observations should be continued. If stirring does not help, a boat's engine should be turned on (gear disengaged) to create a strong water current through the cages.
As soon as the mesh openings appear to be about “50%” blocked by fouling organisms, the cage concerned should then be freed from the bottom water-pipe frame and the net cage hoisted and transferred to the shore for sun-drying. In doing this, and after freeing the cage from the frame, the cage should be disengaged from the raft one side at a time. Concurrently, a new or clean cage should be rigged up into which the stocked fish should be transferred by herding and not by netting.
The fouled net after being exposed to the sun for several days, should be freed from the fouling organisms by “hammering” with a piece of heavy wood.
Raft maintenance is a continuing process to ensure that all joints and floats (drums or plastic containers) are properly secured. Badly rusted oil drums and cracked or badly dented plastic floats should be changed.
Records keeping
All input and output records should be kept for the subsequent assessment of the performance of the trials. Table 6 lists out the salient record items, some of which will necessitate daily efforts.
Acquisition of fish for re-stocking
This is dependent on the future pattern of demand for the product especially in relation to the average wholesale value and the annual cost of the proposed facility input. It also depends upon the utilizability of the area for the fattening of the target and presumably premium-value species.
Should pilot culture trials at this island site be initiated, it would be essential to monitor closely the well-being of the proposed culture systems. If results showed that both the estuarine grouper and mangrove snapper thrived satisfactorily throughout the high salinity periods, there should be no problem of acquiring fish for re-stocking once operations in the lagoon side are established. Should the site prove only suitable for the fattening of the other listed marine species, and at the same time an acceptable profit margin was expected, a young fish collection “depot” should be established at the culture site on the island.
Essential supporting facilities
Storage facilities for keeping “trash” fish feeds are essential especially when the source of such feeds depends on supplies from the peninsular landing sites. Further, irregular supply of “trash” fish at landing sites should also be contemplated especially during the strong northeast monsoon period.
In connection with the above, refrigeration method is only adequate for short periods, say, two to three days at the most. For seasonal situations, the magnitude of such problems will be considerably greater, and attempts should be made to consider alternative feeds in processed form.
Sea transport is another major issue. Apart from transporting young fish for stocking, such transport facility should also be capable of being used as a multi-purpose craft ranging from live fish and fish feed transport (in bulk) between the island and the peninsula, to a general working platform, at an economic running and maintenance cost.
The following assessment of the environment of the lagoon is based on three sets of data. In one (Table 8), the column of the lagoon water at 0.5 m intervals was measured on 6 August 1977 at five stations beginning at the “mouth” of the river (Station 1), then at the opening of the lagoon (Station 2), up to the main channel of its northern section (Stations 3 and 4), and ending opposite the house of a selected fish farmer (Section 5) between 1350 and 1530 hours (Fig. 6) during a flood tide.
The second set of data (Tables 9 and 10) was similarly measured at four stations (Stations I–IV) along a mangrove stream leading into the lagoon, and at three stations (Stations A-C) across the lagoon between the discharge point of the mangrove stream and the house of the selected fish farmer (Fig. 7). In each of the four mangrove stream stations, only one point at 1 m below the surface was measured for all the parameters except dissolved oxygen due to the possible contamination of the measuring probe by the presence of hydrogen sulphide. For the three lagoon stations, measurements were made as of 6 August 1977 occasion except that each of the three stations was measured four times between 1700 hours on 7 August and 0400 hours on 8 August for conditions during the slack periods of an ebb at about 1945 hours and a flood at 0400 hours. This was necessitated by the presumably high productivity of the lagoon waters visually observed on the first day and therefore the possible lowering in both pH and percentage saturation of dissolved oxygen in the early morning hours which could be vital to the present considerations.
The third set of data was acquired during 13–16 November 1977 for the assessment of the northeast monsoon conditions in the lagoon site. In particular, emphasis was made on the influence on the site by mangrove stream and riverine waters, and the resultant conditions in relation to the suitability of the site for the survival of the culture trial fish stocks.
According to the first set of data (Table 8), there was considerable mixing of fresh and marine waters at the mouth of the river (Station 1), at which riverine water dominated the upper meter of the water column and sea water considerably mixed with riverine water hugging close to the river bed below the upper first meter. This is, of course, a classical phenomenon to be expected. Visual observation showed a vivid dark brown water with less than 1 m in transparency, suggesting considerable nutrient enrichment and high productivity. A thermocline (drop of 1°C/m) and a halocline (drop of 1 ppt /m) were clearly detected, and these can be reflected by the significant differences in the pH and dissolved oxygen values.
At Station 2, however, open sea water predominated uniformly throughout the water column as can be seen from all the parameters measured. At this station, the water also showed a green colour typical of shallow sea water, and was relatively less turbid.
Away from the opening of the lagoon at Station 3, mixing of riverine and sea waters again took place showing a very significant halocline between 0.5 and 1 m from the surface. Dissolved oxygen values were however high and in fact over-saturated particularly so over the lagoon bed. This could possibly be due to the comparatively more shallow depth at this station resulting in faster tidal water flow, and also to the dominance of sea waters as shown particularly by the 1-m pH value.
The inner two stations (Stations 4 and 5) have shown more or less similar conditions. In particular, their salinity values suggest a rapid decrease of the influence of riverine waters on one hand, and the possible dominance of sea water on the other. The latter observation is clearly supported by the recorded pH values, all within the normal range of sea waters. At both stations, however, haloclines were detected between 1.0 to 1.5 m at Station 4 and between 0.5 and 1.0, and 1.5 and 2.0 m at Station 5. Although the degree of stratification is considered to be of a much smaller magnitude as compared with the first three stations, the upper halocline at Station 5 in combination with the thermocline between 0.5 and 1.0 m were, at the time, considered to be an unsatisfactory condition, one often resulting in the lowering of dissolved oxygen and pH values in the water column during slack tides and in early morning hours. The relatively high oxygen value recorded for this surface layer was in all probability due to high photosynthetic rates. (It has been most unfortunate that nutrient and chlorophyll levels could not be measured). The gradual but distinct drop in the percentage saturation of dissolved oxygen with depth is especially significant in support of these critical observations. On the other hand, however, the uniformly normal pH values appear to contradict these observations; and the only explanation might be the predominance of sea waters.
This set of data sampled on one single occasion is obviously not representative of the environmental conditions of the lagoon, and in this instance, the proposed culture trial site at Station 5. At best, it might be indicative of presumably abnormally dry August conditions. For such a deeply indented water body, this set of data does pose a number of issues with respect to the dynamics of its hydrography in relation to its suitability (at Station 5) for fish culture. In particular:
The temperature and salinity profiles in the water column during slack and minimal tidal conditions for the wet season;
The possible influence of mangrove stream waters on the lagoon proper during slack and minimal tidal conditions for the wet season; and
In view of the possible high nutrient loads, the conditions of the water column in the early morning hours.
According to Table 3, the onset of the strong northeast monsoon is associated with a peak rainfall averaging 143 cm for the month of November, by which time fresh and riverine waters should predominate the lagoon and, therefore, the influence of sea waters could be restricted to the lower layers of the water column. Such an abrupt change in the hydrographic regime could lead to an increase in dead organic matters and high bacterial activities, and together with the strong freshwater runoffs from the adjacent mangrove streams could result in high BOD and low pH and dissolved oxygen values. These conditions, if true, could create serious adverse effects on the confined fish stocks in the net cages. Further, if stratification was pronounced, the top fresh to near fresh water layers could significantly decrease the transfer of oxygen from the air to the lower water layers during minimal and slack tidal periods. The adverse effects of this condition on the well-being of the caged fish could further be amplified by the trapped metabolites and other organic activities.
These hypothetical issues are extremely vital to the future potential of the lagoon as a fish culture area. Within the limited time, investigation into these conditions have not been possible. Attempts have, however, been made to obtain some indications of the early morning conditions of the water in the lagoon. At the same time, measurement of the waters in a mangrove stream was also made with a view to attempt some indications of any possible relationship between the waters of this stream and the waters across the lagoon channel.
Of the three stations, Station B located at the middle of a transect between the mouth of the adjacent mangrove stream and the proposed culture trial site at Station 5, has only a water depth of about 1.5 m (Fig. 7). Station C has the greatest water depth varying between 2.5 and 3.0 m, and is the same location as for Station 5 (Fig. 6) worked on 6 August 1977.
In general, there was a distinctive drop in pH values and a corresponding decrease in percentage saturation of dissolved oxygen values at all the three stations between sunset on 7 August and 0400 hours on 8 August (Table 10). These are indicative of the presence of a significant abundance of plankton and therefore relatively high nutrient levels in the waters.
Stratifications in the water column was again detected at all the three stations. Of particular note are those at Station C: at 1700 hours, a significant halocline at 1.0 m; at 2345 hours, a thermocline at 1.0 m and three haloclines at 0.5, 1.0 and 1.5 m; at 0400 hours, two somewhat less significant haloclines at 0.5 and 1.0 m. Since slack water conditions appeared at 1945 and 0400 hours, and since the observed haloclines seemed to be more pronounced at 1700 and 2345 hours, it would appear that tidal movement could have been the main cause of such phenomena. On the other hand, the strong cool winds after night fall could have been responsible for the thermocline detected at 2345 hours.
Assuming that if the invasion of tidal sea waters was of a similar magnitude during the wet season, the flooding conditions of the river and the adjacent lowlands in November, for example, could logically be assumed to incur more pronounced stratification in the water column on one hand, and by virtue of the expected increases in nutrient input, to further lowering in both pH and dissolved oxygen values on the other. This latter assumption is especially of importance to the future potential of the lagoons as a fish culture area. In this regard, the effect of the mangrove stream waters is considered to deserve priority attention.
The northeast monsoon conditions as represented by the November measurements, have shown a number of major differences when compared with the August conditions. Despite the increased, near fresh conditions of riverine discharges (Table 11), marine waters under the influence of the strong northeasterly winds and vigorous wave actions rushed into the lagoon and dominated the lower layers of the lagoon waters. The intruded marine waters have an unusually high level of dissolved oxygen, and the oversaturated conditions also affect the upper layers of the water column through vigorous mixing with the over-riding riverine water. Evidence of vigorous mixing of these two sources of water can be seen in the trend of pH values for each of the water column measured, as well as the strong current flow conditions during all tidal periods. The strong northeasterly winds also serve as an effective means to oxygenate the surface water layers irrespective of tidal state or the time of the day in most cases.
Similar situations have also been detected at the three stations along a transect from the mouth of the mangrove stream to the selected culture site (Table 12). Along this transect, it appears that the runoffs of this mangrove stream and others in the vicinity did have certain influence on the culture site. This can be evidenced by reference to both the pH and salinity values for each of the three water columns measured. The well-oxygenated, and in most cases, over-saturated conditions at different water layers should, however, present no problems to the suitability of the culture site.
Table 13 shows the conditions of the mangrove stream at Stations I–IV measured on one occasion in the early part of the afternoon of 14 November 1977. Night measurement should reveal lower values for both dissolved oxygen content and pH.
The strong wave actions and winds are considered to be two beneficial factors in providing a high oxygen budget to the lagoon water and a vigorous mixing of marine waters and riverine and mangrove stream discharges. These eliminate potential adverse conditions over the selected culture site resulting from the influence of mangrove stream discharges.
From the hydrographic observations made on the three occasions, the lagoon at Station 5 (Fig. 6) is recommended as a culture trial site for the pilot project. The shallow nature of the lagoon is, however, considered a natural handicap, but the vigorous mixing of riverine and sea waters coupled with the irregular distribution of sand bars should promote greater tidal water movements, which is considered a beneficial asset from the point of view of oxygen budget. Further, the physical appearance of the area suggests that the lagoon could be a natural spawning, nursery and feeding ground of the giant sea perch, estuarine grouper and the mangrove snapper, three of the target species for culture. This is supported by even the limited evidence from the fishing trials. A more comprehensive fishing survey coupled with hydrographic sampling should reveal the potential of the lagoon as a natural ground for the production of fry and fingerlings of these and other desirable fish species. The suitability of the lagoon waters for the survival and growth of these species can, therefore, be favourably considered at this stage.
The culture system would, however, have to differ from that proposed for Pulau Perhentian Besar by virtue of the differences in both the physical and environmental settings.
The shallow nature of the selected site at Station 5 (Fig. 6) poses the major problem in deciding on a culture systems to be adopted. The choice of permanent or semi-permanent pens in the form of fixed impoundment structures has been thoroughly explored. In the opinion of the authors, any one form of such structures would be undesirable. Their reasons are:
Prior to the completion of the pilot culture trials, and in the absence of a thorough understanding of the environmental setting, permanent or semi-permanent fixtures to be erected at the proposed site is considered unwise;
The construction of such structures may superficially appear to be simple, but in reality involves a number of engineering problems;
Any one form of such structures often imposes upon the confined fish stock a “living space” limitation, and at the same time makes culture management and harvesting difficult; and therefore,
Impoundment culture system tends to have a much lower yield rate on one hand, and much higher facility and management input cost on the other.
In view of these factors, the initial culture trials primarily designed to assess the economic feasibility of introducing this new venture to the lagoon, should adopt the floating net cage method of culture. This will not only simplify culture management, but also enable ease in resiting the invested facilities in case of need.
The species of fish to be utilized should include premium value species readily accessible and naturally found in quantities of different age groups in the lagoon. The giant sea perch (Lates calcarifer), the estuarine grouper (Epinephelus tauvina) and the mangrove snapper (Lutjanus argentimaculatus) should be exploited for this purpose. Other fast-growing species whose fry and fingerlings are found in quantities in the lagoon should also be of potential to the future fish culture in the lagoon. In this consideration, the market value of the cultured species and the location of the consumer market, are the two most vital factors in species selection, especially subsequent to the successful outcome of this pilot project.
The source of fish for initial stocking in the beginning of the pilot culture trials, should come from captures made within the lagoon. Captures can be made directly by the Project's personnel and/or through the efforts of the fishermen.
The conditions of the fish for stocking and therefore those of the captured fish to be retained should meet with the same criteria as set out for the case of Pulau Perhentian Besar.
The recommended culture method is similar to that proposed for Pulau Perhentian Besar but differs in having much lighter raft materials and smaller cages.
Fig. 8 shows the proposed size and design of a unit of double cage bamboo raft floated on ten 44-gallon “flintkoted” oil drums (or 10 styrofoam floats each sealed with a heavy gauge polystyrene sheeting to avoid the settlement of fouling organisms). Ideally, the total length and width of the raft should be about 7.9 m (ca. 26 ft) and 4.2 m (ca. 14 ft), respectively. This will enable the accommodation of two 3 m × 3 m (ca. 10 × 10 ft) cages. The depth of each cage is proposed to be 2.5 m from the bamboo to which it is attached. Assuming a diameter of the oil drum (or the styrofoam float) was 2 feet (or 0.6 m), of which one-third (or 0.4 m) would be submerged, the depth of the cage submerged in water would therefore be about 2.1 m. This gives a clearance from the lagoon bed of about 0.4 m at zero tide.
The stocking of each net cage for the pilot culture trials should involve only juvenile fish of the estuarine grouper at a size of about 150 g, or about four fish to a catty (1 catty = 0.61 kg), at which size this species is expected to have an average daily increment of 2.5 g. For a 150 g fish to attain 915 g (= 1.5 catties), it should take about 306 days. This will mean that the economic feasibility of fish culture in the lagoon, as far as this grouper is concerned, can be ascertained in less than a year. Being a fattening process, this approach has also the merit of initially avoiding the considerably more complicated task of the nursery of this species.
To further simplify the system, the initial stocking density (number of fish per unit area or volume) should be determined by an estimated yield rate at harvest, varying between 8 to 12 kg/m3. If the expected 2.5 g/day weight increment could be realized, this would mean an initial stocking density of 10 to 15 fish/m3, or approximately 180 to 270 tails of 150 g juvenile grouper per cage.
The 8 to 10 kg/m3 yield rate suggests a total yield of 144 to 216 kg/cage of approximately 3 m × 3 m × 2 m. From a surface area estimate, this is equivalent to 160 to 240 metric tons per hectare per 306 days.
For the initial trials, it is suggested to attempt the mean stocking density, i.e. 12.5 or thirteen 150-g fish/m3.
Since it will not be possible to acquire all 150-g fish for the initial trials, the stocking density would have to be determined in accordance with the hypothetical average weight increment rates given in Fig. 9. In the figure, 150 g is considered to be an arbitrary point at which a fish more or less than this weight should have a different daily weight increment rate. Since this is a hypothetical demarcation, and if the available specimens for stocking ranged between 100 to 200 g, the 10 to 15 kg/m3 should still be adhered. In this event, however, it would be essential to separate the stock in accordance with “size” groups, so that each cage will hold specimens as far as possible, of an even size with at the most a range of 50 g. In calculating the initial stocking density, it is important to bear in mind, though arbitrary, that specimens less than 150 g would have a daily increment of 0.8 g, and those having 150 g and heavier should have the mean target of 2.5 g. Such a calculation does not have to be rigid in so far as the number of “undersized” fish is concerned. In the interest of obtaining reliable information in the first year's operation, however, it is essential that all fish stocked should be provided with a record of initial stocking weight.
Should the mangrove snapper be found in abundance, it would be advisable to include this species in the initial culture trials. In which event, an additional two-cage raft should be considered to be equally shared by the two operators. If a daily weight increment of 2 g was used as an initial estimate for the growth of this snapper, 380 days would be required for a 150 g juvenile fish to attain 910 g (ca. 1.5 catties). In calculating the initial stocking density and using an assumed biomass of 10 kg/m3 at harvest, 11 or 12 fish/m3 should be attempted. The total stock per cage at initial stocking is, therefore, 198 tails of 150 g fish. Again, as for the case of the estuarine grouper, fish less than 150 g should be expected to have a much smaller average daily weight increment.
This formed the main activity of the second part of the work programme of the team within the period from 10 August to 8 October 1977. In view of the lack of land-based facilities at Pulau Perhentian Besar and sea transport for the Project, this work was concentrated in the lagoon. A summary of the work programme for this part is presented in APPENDIX A.
The selection of the culture trial site for the lagoon is based on the work presented in the foregoing section. The final confirmation of the suitability of this site will have to await the results of the actual culture trials.
Three bamboo rafts were constructed each as shown in Fig. 8. Each piece of bamboo (green) measures 10 to 13 cm in diameter at its base, and 11 m in length. These were rigged into a rectangular raft with galvanized iron wire (SWG No. 12). Each raft is then attached to ten empty 44-gallon oil drums, each secured in place also with galvanized iron wire. Each raft is so designed that it accommodates two 3 m × 3 m × 2.1 m (length × width × depth) nylon netting cages. Wooden planks are used to provide working platforms.
A total of four large (3 m × 3 m × 2.1 m) and four small (1.8 m × 1.8 m × 1.8 m) cages were constructed. The former each has a mesh size of 5 cm, while the latter comprises two units of 1.3 cm and two of 1.6 cm mesh. The large cages are for fattening purposes while the small ones are for the nursery of fry. Each cage at its open end is provided with a “headrope” for attachment to the raft.
One raft was used for floating two large cages and another for small cages, while the third left as a standby depending on the outcome of the capture of fry and fingerlings to be carried out.
Since conventional metal anchors are too expensive, 12 concrete weights (Fig. 10) have been made for the anchorage of the floating rafts. Each concrete weight was made using half a 44-gallon oil drum filled with cement, sand and stone mixture at a ratio of 1:4:8. Prior to filling this mixture, an iron frame as shown in Fig. 10 was first put inside the oil drum. The exposed round loop of this frame then provides the attachment point for the mooring rope. These weights were used for the mooring of the three rafts as shown in Fig. 12.
The general layout of the culture facilities at the selected culture trial site for the pilot project is shown in Fig. 12. The size of the mooring polyethylene rope is of a diameter of 18 mm. Two of the three rafts were fitted with cages as noted under subsection 5.2 and ready to receive captured fish seedlings. Surrounding this raft area was erected a mono-filament nylon-net fence to prevent the entrance into the area by the sea otter. The total enclosed area is estimated at 31 m × 31 m. The average depth of water within this area is around 3 m at zero tide. Extra support of the gillnet fence is provided by planting along two sides with wooden poles.
With the assistance of the Master Fishermen of the Project, a beach seine was constructed to the design required by the team (Fig. 13). Once shot, this seine gives a swept area of about 33 m and is light enough to be manually operated by six persons. Fish traps were also constructed by the team using 28 mm square meshed galvanized iron netting as shown in Fig. 11. These are connected with 8 mm diameter polyethylene rope at 10 m apart and marked at one end with a plastic float.
A survey of ten different sites was carried out (Fig. 14) along the length of the lagoon for a period of ten days. In addition to the team, six fishermen in the vicinity also participated. Fishing operations were carried out from and with a chartered boat of 12 m length overall (l.o.a.) and a 6 hp inboard diesel engine. Another 3.3 m fibreglass skiff with a 6 hp outboard gasoline engine was used whenever there was the need to transport the captured seedlings to the farm site. Round plastic containers were used for holding fishes of desirable species. Each container has a diameter of 1.5 m and a depth of about 22 cm.
The species and number per species of fish retained for holding in the farm are as follows:
| Species | No. | Common size (cm) |
| Epinephelus tauvina | 185 | 12–15 |
| Lutjanus russelli | 614 | 4–8 |
| Lutjanus argentimaculatus | 54 | 4–8 |
| Lates calcarifer | 46 | 6–10 |
| Lethrinus nebulosus | 1 461 | 4–10 |
Three E. tauvina of 30 cm (total length), two L. argentimaculatus of 30 cm and two Lates calcarifer of 20 cm were among the catches. A summary of seining records referable of the ten fishing locations (Fig. 14) is given in Table 14.
Results of trapping operations were poor in so far as fishes are concerned. Only a few crabs appeared in the very sparse catches. Handlining was also tried, a method most familiar to the fishermen. It however requires special skills in the choice and size of bait and the hooking of the fish to render the captured fish utilizable.
The acquired fish stocks were distributed in the four cages. The discarded species were utilized as feeds. Additional feeds were acquired at the fish landing site at Kampong Mang Kok subsequent to the termination of the capture fish seedling.
Management of culture operations should be similar to those proposed for the Pulau Perhentian Besar site.
In view of the possibility that the lagoon may serve as a natural propagation, nursery and feeding ground of these two species, a fish collecting “centre” should be established along side the culture rafts. The size of fish to be absorbed may range from fry to juvenile fish at a low cost (for 150 g fish, say, at less than M$11 per catty). Fry (say, at 100-40 fish per 610 g) should be separately confined in small-meshed net cages until they reach 20 to 10 tails to a catty by which time the stock should be “herded” into a larger-meshed net cage. Juvenile specimens should be kept separate from the fry stock and by species, for subsequent restocking after the first harvest. The culture facilities for these operations can follow those proposed for the culture trials. Fig. 9 shows the hypothetical average daily weight increment trends estimated for each of the two species.
When other species have to be considered, they can be similarly treated primarily by separating fattening, a fast weight gaining phase from juveniles, from nursery, a slow growing phase from any stage after postlarvae, activities.
The main constraints confronting the development of this site are:
The absence of land-based facilities including dwelling/operational quarters for the operator, and cold storage for maintaining “trash” fish feeds;
Logistical problems in the daily (during calm weather seasons) transport of “trash” fish feeds from the mainland fish landing site(s);
The absence of a suitable multipurpose motorized craft for the transport of fish feeds and fish fingerlings for stocking, harvested fish to the market, and other essential supplies; and
Problems in obtaining fingerlings/juveniles of the proposed species, other than the lagoon species, for the initial stocking.
Although the Project has made provisions to cover these areas of problem, the timing of the initiation of culture trials at this site then becomes dependent on the solutions to these problems.
1 Malaysian Ringgit (M$) 2.35 = US$1.
The programme for implementing the Project's objectives for this site must, by necessity, take these into consideration with a view to integrate and coordinate all “pre-culture trial” activities. With this understanding, the following programme is proposed:
1st to 4th month
Construction of dwelling/operational quarters at a suitable land site that can have easy access to natural freshwater (stream/well) and the earmarked site for the proposed culture raft (Fig. 1, between Stations 2 and 5).
Installation of a generator to provide electricity for general lighting and two 25 cubic feet chest type freezers.
To explore and finalize a scheme with the island's fishermen to buy in live juveniles of fast-growing marine species of groupers, shappers and other groups/species that are of feasible commercial values as listed under Section 3.3.
To transplant 150-g juveniles of the lagoon species (estuarine grouper and mangrove snapper) initially in small numbers to ascertain their ability to thrive under open sea conditions (high salinity) and to observe their problems (through their behaviour, rate of weight gained, and diseases problems) in this coral reef environment.
To construct a temporary two-cage floating raft as designed for the lagoon (Fig. 8) but reinforced the framework by using double the number of bamboo pieces, and with a depth of 5 m for each cage. These two cages are for the holding of fish purchased from the fishermen (in one) and for the acclimatization trial for the lagoon species (in the other).
Feeding of the fish stock should be carried out as proposed under Section 3.3.
Taking advantage of this, the detailed logistics in the acquisition, cost (including transport), availability of the provision of fish feeds, should be carefully and practically worked out. Similarly for the source of fish for stocking.
The adequacy of the outboard fibreglass skiff in satisfying the needs for both the lagoon and island sites should be critically assessed. If there is the need for a second craft, a 20 to 25-foot inboard diesel craft with inboard live fish holds such as those used in Hong Kong should be considered. (This design is a truly multipurpose shallow-draught mariculture craft).
5th to 16th month
As the above provisions and assessments are being finalized, the construction of a four-cage raft (Fig. 4) should begin.
Should the lagoon species thus transplanted manage to thrive and show significant daily weight increment (say, ca. 2 g/day), a large-scale transfer of these species of the same size as the original trial stock should then be made for stocking three of the four cages. The first cage should hold 680 numbers of 150-g juvenile groupers (if size uneven, estimate 10 kg/m3). The second should accommodate 550 numbers of 150-g grouper (or at 8 kg/m3) together with 200 numbers of 150-g snapper (or at 3 kg/m3). The third cage should only hold 550 numbers of 150-g snapper (or at 8 kg/m3). The fourth cage should be allocated for testing the culture of juvenile marine fishes acquired from the fishermen, but the number of species should be restricted to one to two species each of the groupers and snappers. The stocking biomass for the fourth cage should conform with that for the second cage. (For these marine species, the authors are in favour of the red and John's snappers, and the mottled grouper and one of the seabasses).
All input and output records should be kept as suggested in Table 6. These will be utilized for the subsequent assessment of the economic feasibility of marine fish culture at this site on one hand, and for the identification of problems and refinement on other details before restocking in the second year. In particular, information on mortality cases must be thoroughly described for each case.
The cause of fish death utilizing the “sick” fish (placed in a large thermos with ice while the fish shows clear signs of dying) should be studied for internal bacteria/viruses and external (including gills) parasites. Such studies should be taken up by scientific academic institutions and/or the Governments medical and health authorities. The identified agent(s) responsible for the death of the cultured fish should be isolated for tests with drugs and healthy live fish with the object of recommending method(s) for the control of similar future cases.
Water conditions inside and outside the cages for both surface (0.5 m) and bottom (of cage and 0.5 m above the seabed) should ideally be measured each day at about 1000 to 1030 hours for temperature, salinity, dissolved oxygen (then to be calculated as percentage saturation), and pH. If this daily effort is not possible, these parameters should at least be measured weekly during slack periods between two tides. In all cases, details of the time of the day and tidal level information should be properly recorded. In addition, air temperature, atmospheric pressure and degree of overcast should also be entered into the record sheet.
By the time the first year's culture trials are initiated, it should be either towards the end of, or after the northeast monsoon period. Presumably the availability of “trash” fish feed would not be a major problem. It is, however, essential that the Project should also begin a supporting line of investigation to consider the manufacturing of an artificial feed for two purposes: (i) to resolve the feed supply problem at times of shortage of “trash” fish, and (ii) to compare the economic feasibility between “trash” fish and an artificial feed, bearing in mind each of these feeds has its advantages as well as disadvantages. The main advantage of “trash” fish feed, apart from fully utilizing captured products, is its present low costs. If its demand gradually rises as the project's objectives are attained, its value must be expected to increase substantially to such an extent that the production cost per unit weight of the cultured fish would become economically unfeasible. Another disadvantage of a “trash” fish diet is the potential risks of “malnutrition” and disease infection of the cultured fish, especially when the quality and freshness of the “trash” are of a sub-standard nature, bearing in mind the warm climate of the country and the method of preservation and disposal of the captured fish. When artificial feeds are concerned, the problem may not necessarily be one of comparatively higher costs, but rather the arrival initially at a formula that can satisfy the nutritional requirements of the species on one hand, and the great number of fish species that have and will have commercial potentials on the other. It is further complicated by the fact that as far as is known, the groupers are difficult to be trained to accept artificial feeds. Despite these pros and cons there is a definite need to investigate into the formulation of an artificial feed at this early stage for the purposes noted in the aforesaid.
Towards the end of the 12-month period, a thorough assessment of all culture input costs in relation to the proceeds of sale of the harvested stock should be made. This assessment should also take into consideration of mortalities, causes of such mortalities, and all experiences pertaining to operational problems and deficiencies, with a view to refining on culture methods/management for the second year's culture operations, should the level of profit decide the expansion of activities in the bay.
In particular, the adequacy of the skiff (with the twine Johnson outboard engines) in satisfying transport requirements should be assessed. It is at this point in time suspected that a single craft especially one of this nature may not suffice in meeting with the operational requirements from both the lagoon and this island sites. In which case, an additional multipurpose craft with an inboard diesel engine and live tanks preferably with a design such as those used in Hong Kong or equivalent should be contemplated.
In considering the first year's programme for this site, reference should be made to Section 4, especially subsections 4.2 and 4.3. During the November or third visit to the lagoon, it was discovered that a species of puffer (family Tetraodontidae) is a serious pest to cage culture in that it is capable of breaking nylon netting material with its powerful jaws in an attempt to reach the feeds given to caged fish stocks. For this reason, galvanized wire netting is recommended to replace the original nylon materials. Apart from being able to prevent the caged fish from escape, galvanized wire netting has another advantage in that it has a comparatively lower fouling settlement rate.
Unlike the Pulau Perhentian Besar site, the essential land-based facilities can be immediately organized at the house of one of the operators for both the earmarked pioneering fish farmers. The first year's programme for this lagoon site can, therefore, be summarized along the lines proposed under subsection 4.3 as follows:
1st to 2nd month
Construct rafts and net cages as recommended under subsection 4.3 (Fig. 8).
Establish a fry/fingerling/juvenile fish collecting “centre” at the same site for the nursery of fry and conditioning of the larger fish for stocking in the fattening cages.
These should be collected directly by the Project's staff and also purchased from fishermen. Before accepting a fish, its conditions must first be properly assessed as recommended.
All information on the location of captures should be mapped out together with other salient environmental information as far as possible, including date, time, tide, gear, kind of bait, associated fish species, and if possible, salinity and temperature.
Immediate daily measurement of surface and bottom water conditions (salinity, temperature, dissolved oxygen and pH) for both inside and outside the cages should be carried out even prior to the stocking of the fattening cages.
The stocking of the fattening cages should be initiated as soon as there are suitable quantities of fish at the rate recommended under subsection 4.3.
Two 25 cubit foot chest type deep freezers are required for holding “trash” fish feeds in cases of bad weather and minimal landings of fresh fish. Should the existing generator at the operator's family cannot provide the additional power for these, a new generator should be acquired.
Daily operational records should be kept as suggested in Table 6.
3rd to 12th month
Fattening operations continue.
Measurements of environmental parameters continue.
Recording of daily operation continues.
Recommended culture procedures constantly under review with the object of adjusting them to suit the actual situations.
A detailed hydrographic survey should be carried out in November-December to assess the water qualities at and in the vicinity of the site.
An analysis of all results should be made towards the end of this period.
Throughout the period, a survey of the fry/fingerling/juvenile of the two cultured species should be an ongoing project.
Tables 5 and 15 provide a list of materials for the floating net cages for each of the two recommended sites.
For the storage of “trash” fish feeds, it has been proposed in the aforesaid that each of the two sites should be provided with:
Two 25 cubic feet chest type deep freezers; and
A generator capable of serving as an adequate source of electric power for these freezers and other domestic power requirements.
The recently acquired skiff with the twine Johnson outboard engines is expected to serve a useful purpose principally in the efficient transport of “trash” fish feeds and personnel. It is however contemplated that for the future development of fish culture in either the lagoon or the island, there should be a definite need of an all purpose inboard diesel engine craft with inboard live tanks.
The Project has already acquired the following equipment:
A dissolved oxygen and temperature meter powered by rechargeable batteries (charger for 220V A.C.) with a temperature compensated probe and 30 m of detachable cable (portable);
A pH meter operated by mignon batteries (rechargeable battery-type two expensive) with a rugged electrode and membrane (portable);
A PVC plastic water sampler of a 2-litre capacity and a revolving top messenger (light weight, portable; thermometer not required, if required an ordinary one can be fitted); and
A salinity refractometer (portable).
Ideally, ammonia, orthophosphate and BOD should also be measured as they have frequently been found to be responsible either directly or indirectly for adverse ecological stresses on the confined fish stocks. Their measurement is, however, difficult involving much more sophisticated techniques and instrumentation in the laboratory.
These primarily include the following:
A spare supply of nylon twines and ropes for the maintenance of the net cages and occasional need for additional anchors to be rigged up;
Cylindrical lid-type thermos for the storage and transport of the sick fish to laboratories for the examination/study of fish diseases (each of 2–3 litres);
Two aerators should be provided for the lagoon site in case of pronounced stratification in the water column and therefore of potential threat of oxygen depletion during slack tide conditions; such aerators should be the type designed to incur vigorous vertical turbulence by forcing the surface water downwards;
Live fish tanks, portable, light-weight, round (not square or rectangular), either collapsible PVC type or fibreglass, for the transport of live fish;
One electric water pump (not compressor) for the transport of live fish in the tanks noted under (c) above;
If a craft with inboard live tanks is available, items (d) and (e) would be the least preferred in so far as transporting the captured or harvested live fish from point to point; in which case, these two items can then be used on land for the quarantine of fish before stocking and/or other purposes;
Mincer for producing small granules of feeds for the fry (but the mincing process must be conducted on land, not over the raft); it can also be used for the blending of artificial feeds;
Minor tools for rigging rafts, cutting wires, etc.
The first year's trial programme is designed to demonstrate the suitability of the environment for the culture of the proposed species on one hand, and to enable the prospective operators and supporting Government officers to acquire the firsthand practical experience in culture management on the other. More important is the identification of practical problems and areas of deficiency in the proposed programme. These and any other kinds of information to be gained will be utilized as the basis for the future development of fish culture in the areas concerned.
Of the different categories of information required, the seasonal hydrographical features, particularly those of the lagoon, are considered to be of vital importance to the future decision-taking aspects of this Project. The future design of confinement structures and culture management methods will all be determined by the dynamics of the environment.
Along this line of thinking, it is therefore considered that if expertise is required in the initial culture trials, the person or persons to be appointed should be capable of handling both hydrographic and fish culture problems.
In considering the potential source of expertise, it is submitted that such a person or persons should come from the tropical countries of the region, bearing in mind tropical and subtropical fishery problems differ considerably in both principles and the practical approach to solutions.
The common problems confronting the future of marine fish culture development is our present lack of the basic knowledge and/or experience in the following fields:
The artificial propagation of the commercially preferred species, and therefore the impossibility of meeting with the expected expansion in investment, thus resulting initially in the increasing production cost per fish and eventually making further investment economically non-viable;
As investment increases, the present complete reliance on the capture fisheries for “trash” fish feeds similarly leads to the same adverse situations;
The high mortality rate in the nursery phase and another unavoidable mortality rate in the fattening phase, are indirectly incurring higher production cost per fish or lowering the level of net profit to the investor; for this category of problems fish diseases (bacteria, viruses, parasites, etc.) are believed to be mainly responsible, although dietary problems may also play an importalty role; and
Expertise in the fields of engineering (particularly those concerned with material strength and production design) can indeed contribute considerably to our present day concept (of the culturist or biologist) of culture facility designs.
These are regional problems at least within the South China Sea region. Although the species cultured, by necessity, differ from country to country, the need for expertise in overcoming these problems are indeed most urgent. In satisfying this need, it is not merely a matter of acquiring the necessary expertise, it is also a problem involving heavy investments on the provision of the basic facilities and effective organization and implementation of agreed programmes.
It is therefore recommended that the international bodies concerned consider medium- and/or long-term investments in tackling these basic problems from a practical approach with academic input where necessary (e.g. in fish diseases and nutritional problems). As far as expertise is concerned, again for practical reasons, experienced scientists in the region should be explored as far as possible.
For the first year's trial programme, it is proposed that the Project should have a team of personnel comprising the following:
A team leader, preferably an experienced senior fishery biologist of the Government of Malaysia, who has worked on fishery problems of an investigatory nature (capture or culture) and background experience in general hydrography.
A UNDP/FAO appointed marine fish culturist with thorough experience of tropical marine fishes and tropical hydrography, who will work as an adviser to the team leader. His tenure may be intermittent as required.
Supporting staff should comprise the following Malaysian personnel:
One experienced technical extension officer capable of handling technical field operations required by the project (knowledge and experience of running outboard engines preferred);
Two junior technical extension officers capable of supporting their senior with the least direct supervision, and responsible to their senior in assisting in all field operations, and in helping the operators at the two culture sites in various ways including in particular the keeping of all records;
The three operators at the two culture sites should also be considered as part of the team, with whom close liaison should be maintained.
A senior Malaysian officer is recommended to be the team leader because of his more thorough appreciation of the socio-economic and other subtle problems inherent in his country, and also because by following through the initial trial culture period, he can provide continuity to the subsequent phases of the development of this Project. He should, however, be given the necessary incentive and appropriate level of authority in making decision in consultation with his adviser within the interest of the Project.
The UNDP/FAO appointed adviser's responsibility is primarily two-fold: (i) to ensure that all decisions taken by the Project are professionally correct; and (ii) to transfer his knowledge and experience to the Malaysian team as much as possible.
The need of expertise in subsequent years should be determined by periodic review of the development potentials of the two culture areas. Should such reviews are in favour of a full-scale development, an assessment of the annual requirements of fish for stocking, “trash” fish feeds, and other essential production input items should also be critically made. Such an assessment will provide reliable indications of need to venture into the four problem areas outlined in subsection 7.2.
At this point in time, it is necessary to assume that these areas of development would be required, since the organization of such activities is both time-consuming and logistically difficult.
Although it is beyond the terms of reference of the authors, the Project should also take into consideration, in addition to the provision of a hatchery, the provision of expertise for the development of artificial feeds, the study of fish diseases and the introduction of better culture facilities than what are proposed.
If the first year's programme showed that marine fish culture was an economically viable investment, a significant increase in the number of operators should be expected. While this may lead to the initial attainment of the Project's objectives, the implementation of the development plan has to be carefully controlled from the onset. This view is taken for the following reasons:
The supply of “trash” fish may not necessarily be adequate in coping with an abrupt increase in demand, especially if the capture fisheries show seasonal fluctuations in landings, thus resulting in higher feed cost and periods of supply shortage.
New operators may select culture sites for their own convenience.
Resulting from (b), conflicting problems may arise with other authorities (e.g. port authority) and anchorage rights of the capture sector of the fisheries.
As this develops, at least the level of nutrient pollution can be expected to increase through increasing land-based activities catering for the culturists and indeed through the culturists themselves.
The problem of “poaching” will for certain be a serious one, and associated with it will be problem over legitimate and illegitimate claims of theft.
The common “middleman” problem will arise controlling and under-cutting the level of profit of the culturists.
All these and other problems should now receive consideration with the object of introducing legislation for regulating and enabling the future development of this Project. The actions required can be classified as follows:
From the fish landing statistics, the monthly average supply and value of the “trash” taxon (Table 4) by gear should be worked out for each of the fish landing sites easily accessible to the culturists at the two selected areas. This set of information should provide a reliable pattern of the availability and value of the “trash” taxon, as well as those of other taxa of perhaps higher average value but can be considered as additional source of feeds. Should this show seasonal shortage in supply (for example during the northeast monsoon period), immediate action should be taken to devise artificial feed utilizing as far as possible local ingredients to reduce input costs. In this line of thinking, however, the estuarine grouper will present the major problem in that unless thoroughly trained from the beginning, it is unlikely that it would accept artificial feeds. In this connection, the deep freezers proposed for the two sites will have to be fully utilized for the stocking of fish feeds. Another possibility of overcoming such situations is to have the Project's fish culture team and the operators to conduct fishing (preferably purse-seine) in the lagoon (where sea conditions may be more favourable) for feeds at times of shortage of fish at the landing sites.
A new set of legislation should now be considered to set down the main criteria for site selection, to earmark sites for potential new operators, to make provisions for the recognition of the operator's rights to his fish and culture facilities, to set down legal measures to control poaching and other related civil problems that may be arising, to ensure that fish culture activities will not become a source of pollution, to discourage the potential creation of land-based sources of pollution, and to require future operators to provide annual input and output records.
The logistics of what might be the future infrastructure of this new form of fish production should now be considered with the object of identifying the interrelationships among the different principal activities from fry production (whether capture or induced spawning) and different supporting activities during the fattening phase) e.g. the capture sector, demand and supply of “trash” fish feeds, possible control of fish agents, etc.) through the disposal of products (transport logistics, transport cost, preference of each potential market, freshness of products, etc.) to the consumer markets (local and overseas, form of product required, possible control of agents at different points, etc.). With such an infrastructure, it would be possible to design effective product disposal methods, to organize efficient transport systems, to identify local and overseas markets, to minimize undercutting of profit by agents, and to maximize economic return in favour of the culturists.
