The cage culture of coral reef
fishes and other fishes
in Sabah, Malaysia*
Rooney E. Biusing[1], Michael Phillips[2], and Annadel S. Cabanban[3]
Abstract
The cage culture and live fish
trade of coral reef fishes and other marine species in Sabah contributes to the
production of aquaculture for Malaysia.
In has been in Sabah only in the last 10 years but the operations have
generated income of RM 403,000 in 1993 (1 US $ = 2.5 RM), representing 6.8% of
the national volume that was exported.
This contribution increased to 15.2% in 1994. The potential for aquaculture in Sabah, including cage culture
and the live-fish trade for coral reef fishes and other marine species, is
great. Various aspects of the industry
was studied under the formulation of the Master Plan for Aquaculture in Sabah
by the Department of Fisheries, Sabah (DoF) and the Network of Aquaculture
Centres in Asia-Pacific. Surveys of cage culture areas and questionnaires were
used in the study. The aspects
pertaining to the culture and live fish trade of coral reef fishes and other
marine organisms are excerpted and presented here. Cage culture operations are of the cultivating type and holding
type. Fingerlings of groupers (7
spp.), wrasses (2 spp.), snappers (as least 3 spp.), and trevallies (2 spp.)
were taken from the wild. Fingerlings
of seabass (Lates calcarifer) are the only seeds produced in the Tanjung
Tajuk Hatchery of the DoF. The
fingerlings are stocked in two types of cages: cultivating type for 8-12 months
until about 500 g to 1.2 kg; holding type for 3-7 days in transit for domestic
or international markets. The yields
of the cultivating type are low primarily due to the insufficient supply of
fingerlings of coral reef fishes from the wild and the seabass fingerlings from
the hatchery. The economic analysis of
the cage culture in Sandakan Bay show those small-scale cultivating farms are
operating at a loss while the commercial holding type cages are
profitable. The survival of the
small-scale farms is due to subsidies on cages, boats, and unpaid family
labour. The commercial farms are profitable due to the high market prices of
live fishes despite the cost of transport.
Development of breeding and hatchery is one of the recommendations put
forward to increase the productivity of small-scale cultivating cage farms.
Introduction
The export of
marine fishes, particularly coral reef fishes, from Malaysia is a significant
component in the income from marine fish production. The export has been increasing from 200 MT in 1990 to 800 MT in
1994 (Figure 1). This quantity was
valued at RM 200,000 and RM 700,000, respectively, and is economically
important.
Export of marine
fishes for the live fish trade from Sabah only began in the last 10 years. However, records of this development and of
cage culture are few and not readily available. In 1993, the value of the exported products of grouper, seabass,
snapper, and red Tilapia was about RM 403,000, representing 6.8% of the
national volume exported. In 1994,
this contribution increased to 15.2%.
Figure 1. Increasing quantity and value of export of live fishes from
Malaysia and the constribution of Sabah in 1993 and 1994
The live fish
trade particularly of coral reef fishes in the region has been both good for
the economies of these countries but is also brought environmental concerns and
resource management issues (e. g., Johannes and Riepen, 1995; Rubec,
1988). In order to utilise sustainably
the coral reef resources in Sabah for the live fish trade, the culture,
marketing, and the constraints in the cage culture of coral reef fishes were
included in the preparation of the Masterplan for Aquaculture in Sabah. Excerpts of the findings of the study
conducted are presented here.
Data presented here were collected through detailed
questionnaires that were administered to aquaculturists in Sandakan and
Tawau. Additional data were collected
from workshops held in these two locations.
The information on aquaculture was also gathered through review of
secondary knowledge, collected from governmental organisations and other
sources, extensive consultations with individuals from government and
semi-government organisations and the private sector, and field visits to
aquaculture farms and coastal areas of Sabah.
Species cultured
A variety of fishes
are cultured in cages in Sabah. Eleven species
are coral reef fishes belonging to the families Serranidae, Lutjanidae, and
Labridae (Table 1). In addition 3
non-coral reef species are also cultured, namely, 2 species of Carangidae, Caranx
sexfasciatus and C. malabaricus, and one species of Latidae, Lates
calcarifer.
It is a common
practice in all the districts to culture several fishes together in cages. The composition of fishes in the cages is
dependent on the availability from wild sources. For example, in Kudat, fish-farmers can culture the wrasse, Cheilinus
undulatus, with other coral reef fishes because it is common there.
Table
1. Species of fishes cultured in
marine fish cages in Sabah
|
Species |
Common Name |
Location |
Importance |
CORAL
REEF FISHES
|
|
|
|
Family Labridae
|
Tuskfishes, wrasses |
|
|
Cheilinus
undulatus
|
Humphead wrasse, Napoleon
wrasse, Maori wrasse |
Kudat, Semporna, Tuaran |
Major species |
Choerodon
schoenleinii
|
Black-spot tuskfish, Green wrasse |
Kudat, Semporna |
|
Family
Lutjanidae
|
Snappers |
|
|
|
Lutjanus argentimaculatus |
Mangrove red snapper |
Beaufort, Pitas, Sandakan, Tuaran |
Major species |
L.
johnii
|
John’s snapper, Golden
snapper |
Beaufort, Pitas, Sandakan, Tuaran |
Major species |
|
Lutjanid sp. |
Red snapper |
Beaufort, Kudat, Pitas, Sandakan, Tuaran |
|
Family
Serranidae
|
Groupers, coral trout |
|
|
Cephalopholis
miniata
|
Vermillion grouper |
Kudat, Semporna, Tuaran |
|
C.
sonnerati
|
Tomato rockcod |
Semporna |
|
|
|
|
|
|
Cromileptes
altivelis
|
Humpback grouper, Mouse grouper |
Kudat, Semporna |
Major species |
Epinephelus
tauvina
|
Greasy grouper |
All districts |
Major species |
E.
bleekeri
|
Bleeker’s grouper, dusky tail grouper |
Semporna, Kudat |
|
E.
malabaricus
(or altifontalis) |
Malabar grouper, Green grouper |
Sandakan, Kuala Penyu |
|
Plectropomus
leopardus
|
Leopard coral trout, Blue-spotted seabass |
Kudat, Semporna |
Major species |
NON-CORAL
REEF FISHES
|
|
|
|
Family
Carangidae
|
Jacks, Trevallies |
|
|
Carangoides
malabaricus
|
Malabar trevally |
Kudat, Sandakan, Tuaran |
|
Caranx
sexfasciatus
|
Bigeye trevally |
All districts |
Major species |
Family
Latidae
|
Seabass |
|
|
Lates
calcarifer
|
Seabass |
Pitas, Tuaran |
|
Aquaculture
Practices and Management
Source of
Fry/Juveniles
Live fish culture
is highly dependent on seeds from the wild; hatchery production of the marine
fish industry is new. Cage culture for
coral reef fishes relies entirely on the supply of wild seed that are caught by
fish traps, long lines, hooks and gill nets.
Poisons like sodium cyanide is used occasionally to catch fry or
juveniles but these have low survival rates.
For other fishes like Lates calcarifer, the Department of
Fisheries in Tanjung Badak, has produced 11,000 fingerlings in 1993 but this
did not meet the demand of the operators.
Fingerlings are either taken from the wild or
bought, depending on the size of operations.
Small-scale operators collect target species of fingerlings from their
catches as fishermen or buying these from other fishermen. This is done by cage-farmers in most
districts (Table 2). Large-scale
operations purchase fingerlings and marketable-sized fish from fishermen.
Culture Systems
Coral reef fishes
are cultured in two types of cages for the live-fish export market. The (1) cultivating type is used for
growing-out for periods of 3-12 months or more and (2) holding type is
used for temporary culture for 2-10 days while waiting for export. Fishes from the cultivating type cages are
sold to operators of holding-type cages.
In some cases, operators use both type of cages and statistics do not
distinguish the two types.
The marine cages
used in Sabah are simple and practical.
The cages are box-shaped with nets made of polyethylene line and mesh
sizes ranging from 0.5” to 3” or 4”.
Two to four cages are set within a raft frame. Small cages (1 m3) are used for nursing small fishes
while the larger cages (up to 93 m3) are for cultivation of larger
fish. The cages are covered with nets
to prevent fish from jumping out (especially during rough weather) and for
keeping bird and mammalian predators out.
The number of cages
per farm is variable, ranging from small-scale operators with two cages, to
large operators with >10 cages. The
basic features of these operations are summarised in Tables 2 and 3.
Table 2.
Characteristics of marine fish cage operations surveyed in Sabah
Features
|
Districts
|
||||||
|
|
Beaufort
|
Kuala
Penyu
|
Kudat |
Pitas
|
Sandakan
|
Semporna
|
Tuaran
|
|
Number of farmers surveyed |
1 |
2 |
2 |
1 |
10 |
2 |
1 |
|
Average cage volume (m3) |
12.1 |
27 |
8.7 |
16.2 |
13.8 |
48.6 |
1.7 |
|
No. net cages/farm |
2 |
2 |
12 |
2 |
5.5 |
10.5 |
20 |
|
Total volume/farm |
24.2 |
54 |
104.4 |
32.4 |
75.9 |
520 |
34 |
|
Stocking density |
1.5 |
1.9 |
23 |
2.4 |
.06 |
6.1 |
6.6 |
|
Average yields (kg/m3/yr) |
2.1 |
2.2 |
34.5 |
3.1 |
1.45 |
45* |
9.8 |
|
Survival (%) |
80 |
80-90 |
70-85 |
80-90 |
80-100 |
80-90 |
60 |
|
Annual production/farm (kg) |
50 |
120 |
3,600 |
100 |
110 |
23,400 |
333 |
|
Site environment |
Saltwater creek |
Saltwater creek |
Open coast |
Mangrove creek |
Estuarine/ open coast |
Open coast |
Estuary |
|
Source of fingerlings |
Local catch |
Local catch |
Local catch |
Local catch |
Local catch |
Local Catch |
Local catch |
Stocking Density
Stocking densities are below
the optimum capacity of the cages in all districts. Fish stocking densities varied considerably from 0.6 kg/m3/yr
to 23 kg/m3/yr (Table 2). Several factors affect stocking density,
such as the cultured species, fish availability, size-at-stocking, cage dimensions
quality of water, velocity of water, and availability of capital. The availability of fingerlings appear to be
the crucial factor that limits stocking density and production in Sabah and
this situation is a reflection of the difficulty and availability of obtaining
fingerlings to stock cages.
Stocking densities
and duration also vary with the type of culture system. Culture farms use lower stocking densities
than the holding cage operation. In the
cultivating type cage, fishes between 100-1,000 g are stocked while in the
holding type, 1,000-g or heavier fishes are stocked. Fishes are kept longer for 3-12 months or more in cultivating
cages but only for 2-10 days in holding cages.
Feeding and Routine Management
Feeding is
dependent on the type of culture system.
Feeding is only done in cultivating type cages; holding type cages
starve the fishes for a few days prior to transportation. Trash fish is the main feed used in all
finfish cage culture in Sabah. Some of
the species in this group are Sardinella fimbriata, Nemipterus
spp., Caranx leptolepis but the composition vary with the fishing
ground. Trash fishes are caught by the
farmers or purchased from the catches of trawls, purse seines, lift-nets, and
gill nets. The price of trash fish
range from RM 0.20-0.60/kg. Fresh
trash fish costs 10% more than frozen ones.
This feed is available throughout the year, especially near landing
sites in Sandakan, Kudat, and Semporna but is sometimes unavailable in areas
away from main fish landings like Tuaran.
The feeding rate of
caged fish depends on availability of trash fish, size of cultured species or
total weight of cultured fish. The cage
operators feed big fish or those near marketable size at 2-4% of body weight
every other day. Small cage farmers
feed the small fishes, ranging from 100-300 g, at 3-10% of body weight twice a
day. There is no information on food
conversion rate but 5:1 to 10:1 is normal in farms using trash fish.
Most holding cages
in Semporna and Kudat keep fishes for 3-7 days without feeding. These fishes are kept in the cages for this
period for conditioning prior to packing for local and foreign markets.
Maintenance of cages is basic. Fouling organisms in cages are removed, as
these tend to restrict water flow through the cages.
Duration of Culture
The period of culture ranges
from 7 days to 12 months but the taken to reach marketable sizes varies
according the size at stocking, the species, and the type of cage culture (i.
e., shorter period for holding cages and longer period for cultivating
cages). The following practices are
observed in the culture of coral reefs fishes:
·
Short culture period – Individuals nearing marketable sizes are purchased
and fed for 1-4 weeks. Individuals
that have reached marketable sizes are packed and exported as live fish. This practice is common in Semporna and
Kudat.
·
Variable culture period - Fishes about 7 inches in length and
longer (but weighing less than 1,000-1,500 g) are held for variable periods of
time, ranging from 1-8 months, depending on the size at stocking.
·
Long culture period – Most of the fishes caught by
fishermen for the cage culture are between 2-7 inches in length. These small fishes take 8-12 months
(sometimes more) to reach marketable size.
The snappers, L.
argentimaculatus and L. johnii, with initial sizes of 300-600 g
generally take 3-6 months to reach marketable size of 500-1,200 g while the
grouper, E. tauvina and C. miniata of 150-300 g take 6-12 months
to reach the same marketable size.
Survival Rate
The sources of mortality are
the method of catching fishes, the stress during at the first week of stocking,
and poor quality of water. Small fishes caught by gill net and long lines have
high mortality. Fingerlings caught
with sodium cyanide also have high mortality. Farmers report high mortality
between 40-70% during the first week of stocking.
Survival of fingerlings in
cage culture is high after the acclimation period but slightly varies among
species of coral reef fishes and seabass. For Cheilinus undulatus and Choerodon
schoenleinii, survival was 60-85% after a 12-month rearing period in Kudat.
For Lutjanus spp., Epinephelus spp., and Caranx spp. tend
to have survival rates of more than 80% in most areas. Likewise, for
hatchery-reared seabass, survival rate of around 80% is reported in Sandakan.
However, survival rate of E. tauvina, C. miniata, L. argentimaculatus,
and Caranx spp. was lower than the average at 60% in Tuaran. This low
survival rate may reflect the poor growing conditions, possibly related to the
water quality of this estuarine area which is unsuitable for coral reef fishes
that grow naturally in poor-nutrient and clear waters (Sale, 1980).
Farm Production and
Yields
Statistics on live
fish culture in Sabah is limited to 1993 and 1994. In 1993, the value of the production was about RM 403 M (Figure
1) that was produced by 86 farmers. In 1994, the production was 800 tonnes by
117 operators. These figures include the production for grouper and snapper as
well as non-reef species as seabass and red Tilapia. Marine cage culture
production is highest in Sandakan, Kota Kinabalu, and Kudat (Figure 2). All the
other districts produce lower than 100 tonnes.
The production
statistics in 1994 does not agree with field surveys undertaken by the project
(see Table 2). This suggests that the “production” is likely from holding
operations that are common; only Tuaran and Beaufort have “culturing type”
only. From the survey, the output of the cage culture in Sabah ranged from 50 to
23,400 kg. The highest production came
from Semporna at 23,400 kg from only 2 operators who run holding type
system. The production statistics is
more appropriately the output of cage culture in Sabah.
In terms of number of farmers, there are two
centres of cage culture in Sabah. Sandakan, in the east coast, has 47 farmers
who are working on both holding and culture types. Tuaran, in the west coast, has 24 farmers who are involved in
culture type only. All the other districts have less than 20 farmers working on
the industry. Production of live fishes is poorly but positively correlated
with the number of farmers (Figure 3) such that Kota Kinabalu, that has only 7
farmers, has produced second largest production at 255 tonnes in 1994 by
holding live fishes for export. This
indicates that productivity of the farms is not dependent on the number of
farmers but on the type of cage culture and the stocking rate.
Figure 2. Output of cage culture in all districts in Sabah in 1994
Figure 3. Positive relationship
between number of farmers and output of cages in Sabah in 1994
To enhance
production, the government of Sabah has given incentives to fish-cage
culturists. During 1991-1993, the Department of Fisheries provided material
support to 20 and training to 46 fishermen and public. KoNelayan, the
semi-government cooperative for fishermen, likewise provide similar incentives
to promote the involvement of fishermen in cage culture.
The fish yields
from cages were variable and depend on stocking density, survival rate,
quantity and quality of feed, cage and water management, experience of
operator, and the species. The average yields were higher in holding operations
up to 45 kg/m3/yr and lower for culture operations, ranging from
1.45-45 kg/m3/yr. The yields in cage culture are lower since the
sizes of the individuals are smaller than in holding cages. However, cages that
yield less than 10 kg/m3/yr are considered very low yielding. This
reflects poor utilisation of cage space with low stocking rates because of
shortage of fish seed. Farmers in Kudat and Semporna address this problem by
stocking cages with ornamental fishes (Platax spp., Chaetodon
spp.) and highly priced lobsters.
Marketing
and Economics
Live fish is handled properly in order to
ensure the best prices in domestic markets or in Hong Kong. Marketable sizes at
about 500 g or bigger but there is no grading done at the farm. Different markets
prefer particular sizes. For instance, Hong Kong prefers 600 g to 1.2-kg size
for groupers. Selected individuals for
the market are then transported in trunks with aerated seawater tanks to the
local market or to holding tanks before export. It is a common practice for
live-fish to be held in a tank for 1-2 days without feeding. The temperature is
lowered to reduce metabolic rate and oxygen consumption thus decreasing the
mortality rate during transportation.
The packaging is
crucial as well in ensuring the best prices for the live fishes. The custom is to pack the live fishes in
oxygenated plastic bags at about 4-5 kg of fishes per bag. Four plastic bags
are layered for each 4-5 kg of fishes to prevent leakage of seawater. The bags are
then packed into styrofoam boxes or in cardboard boxes. Live fish from Sabah
are then exported by air.
The economic
returns from the cage culture of live fishes are variable among the farms. The
costs and returns vary among the districts (Figure 4). The rate of return in
1994 ranges from 25.3% to 35%, equivalent to a net profit of RM 15.00/m3
and RM 66.6/m3.
Figure 4. Economic costs and benefits of cage culture
in Sabah
The cage culture in
Sandakan was studied in more detail in Sandakan to know the production and
economics of culturing live fishes. The analysis is based on 15 cage farmers
with a cage culture area calculated on the surface area of all cages in
Sandakan Bay in 1995. The results show production of cages, productivity of
farms, and income generated by farmers are variable. In this district, the
average cage volume is 62.17 m3 (s.d. = 37.87). The surface area of
cages per farm ranges from 3.35 to 65.49 m2 or an average of 26.05 m2
(s.d. 10.10). The annual
production per farm is 205 kg (s.d. 202) and the average productivity is 3.89
kg/m3/yr (4.07) or 7.88 kg/m2/yr. The farmers quote RM
13.65/kg on average for the live fish in 1995. Thus, the total revenue per farm
is RM 2,972.58/farm or RM 56.76/m3/year, or RM 464/acre/year.
Furthermore, the
net revenue received by farmers is negative due to the relative higher costs of
inputs over revenue as productivity is low (Table 3). The losses are RM 3,273.11/year/farm, or RM 74.17/m3/year/
or RM 598.755/acre/year. The likely reasons that farms have continued to
operate are due to the subsidy on engines and cages and unpaid family labour.
The analysis further suggests that small-scale cage farming as practised at
present is not a financially sustainable activity unless farmers can increase
stocking densities to improve yields and economic returns. In contrast, holding operations are
generally profitable with lesser costs on operations but with high cost on
packing and transport. The costs for
packing and transport are greatly offset by the high prices that domestic and
international markets pay for the live fishes.
Table
3. Cost components and revenue per farm
per acre for cage culture in Sandakan in 1995
|
Item |
Income |
|||
|
|
(per yr/farm) |
(per/yr/m3) |
(per/yr/acre) |
|
|
Total Cost |
6,245.69 |
130.94 |
1,063.424 |
|
|
Variable Cost |
3,109.17 |
61.03 |
504,824 |
|
|
|
Labour |
737.02 |
15.3 |
122,685 |
|
Feed |
740.31 |
14.00 |
116,081 |
|
|
Seed |
766.73 |
15.58 |
127,516 |
|
|
Fuel |
865.11 |
16.15 |
138,542 |
|
Fixed Cost
|
3,136.52 |
69.90 |
558,599 |
|
|
|
Land rent |
0.32 |
.0052 |
50 |
|
Depreciation cost (cage, engine, Boat, trap) |
2,931.03 |
65.84 |
522,009 |
|
|
Opportunity cost of Investment |
205.17 |
4.06 |
36,541 |
|
|
Overhead cost |
- |
- |
- |
|
|
Total Revenue |
2,972.58 |
56.76 |
464,668 |
|
|
Profit |
- 3,273.11 |
-74.17 |
-598,755 |
|
|
Return to land |
-3.272.79 |
-74.16 |
-598,705 |
|
|
Return to labour |
-2,536.09 |
-58.87 |
-476,070 |
|
|
Net revenue |
- 136.59 |
-4.27 |
-40,156 |
|
Problems in the Industry: Constraints
The problems faced by the live-fish trade of
coral reef fishes and other fishes in Sabah are varied, ranging from the
technical aspects of culture to the social aspect. These problems impose
constraints in the growth of the industry. These problems, that are generally
common in all districts, are summarised below.
Fish Diseases
Fish diseases are a
common occurrence in fish cage culture in Sabah as it is elsewhere (see Chinabut,
this volume). Fifty three percent of fish farmers (20) interviewed reported
mortality of individuals due to diseases. The diseases found were “reddish
skin” (35% of sample), “abdominal inflammation” (35%), “red boil” (20%), “fin
rot”, eye infection, and others. Bacterial diseases causing fin rot are
attributed to Myxobacter sp. and Vibrio spp. and Brooklynella sp. These bacteria
cause extensive skin damage and subcutaneous bleeding in the estuarine
grouper.
Susceptibility of
fishes to diseases is attributed to two factors. The strong winds during the intermonsoon season appear to set
conditions for “tail rot” and eye infection in Semporna. In Pitas, the flood
season was correlated with fish eye damage. The use of destructive fishing
practices, namely the use of sodium cyanide and fish-bombing, was identified as
the reason for fin rot in Kudat (1 farmer). The use of poisons is a possible
reason as this poison stuns fish for easy capture and somehow cause morbidity.
However, the use of fish-bombs is unlikely reason for fin rot in cage culture:
fish-bombed fish hardly survive the damage on the gas bladder as a result of
the blast and as such these fishes are could never reach the farmer.
Regular and basic
fish health checks were conducted only in Kudat but most farmers in Sabah are
not familiar with the proper procedures for maintaining good health in cultured
fishes. Even when fish diseases were observed no treatment was applied on
affected fishes. In Sandakan, Semporna, Kudat, and Tuaran where skin diseases
(fin rot), mouth infection, and eye infection were reported, the affected
fishes were taken out of the cages and transferred to another cage. Cages were
the diseased fishes had been taken were cleaned.
The mortality of
fishes due to diseases is significant and causes loss of income. The losses of
income from bacterial diseases was 5% (Sandakan), from fin rot and eye
infection was 10% (Semporna), from fin rot alone was 30% (Kudat), and from skin
and mouth damage was 60% (in Tuaran; Ostrowski, 1993).
Water quality
The quality of the water in
the cage culture in Sabah is assessed subjectively and no farmer undertakes
monitoring of water quality. Poor water quality is a problem in the cage
culture of fishes in Sabah. Turbidity or pollution from domestic and industrial
sources causes poor water quality in 8 of the 22 farms. Salinity fluctuation
was also reported in estuarine areas but salinity changes are natural.
Fingerling
supply and quality
The shortage and
the quality of the fingerlings of coral reef fishes to stock cages are a
problem of farmers in Sabah. The shortage of grouper fingerlings was noted in
Kudat and in Tuaran (Ostrowski, 1993). The use of sodium cyanide also results
to poor quality of the fingerlings that susceptible to diseases and resulting
to high mortality. This situation is a reflection of the state of the coral
reefs, low recruitment, destructive and unselective fishing, and possibly
overfishing.
Fingerlings for L.
argentimaculatus and L. calcarifer are also not sufficient.
Fingerlings of the seabass produced by Department of Fisheries and Fishermen’s
Cooperative (KoNelayan) in the Tanjung Badak Hatchery were distributed to
farmers but this was not enough to satisfy demand.
Environmental
Impacts of Wild Juvenile Harvesting
Harvesting of juveniles of
coral reef fishes for the cage culture in Sabah can lead to overfishing. With
the harvest of young individuals, fewer individuals grow to maturity. The
consequence of this growth overfishing is lesser number broodstock and
recruitment. Overfishing of coral reef fishes for the cage culture is in a way
an indirect effect of the live-fish trade that utilises undersized fish for
culture at varying periods prior to marketing.
Poor capture and handling
practices can lead to additional destruction of coral reefs (Johannes and
Riepen, 1995). Juveniles are captured using sodium cyanide that kills other
marine organisms besides corals (Rubec, 1988). The poison is used in
combination with a net that is encircled around a coral head or cave. The
poison is to stun the fish to facilitate capture. Coral reefs are already
facing destruction from fish-bombing in Sabah and further loss of live corals
from the local effects of sodium cyanide can contribute to the deterioration of
the coral reefs (Ostrowski, 1993).
The use of poisons and
compressed air (hookah) has also detrimental effect on the health of the
fishermen. There are reports of
paralysis resulting from anoxia due to contaminated air tubes or a death in one
fishing village due to cyanide fishing.
Social conflict
In addition to the technical problems in the culture
of marine fishes, social conflict is also a constraint. The conflicts arise
from theft and poaching of cultured marine fishes from cage farms in Sandakan,
Semporna, Kuala Penyu, Beaufort, and Kudat. In Sandakan, 30% of farmers had
lost fish from poaching. One farmer has lost as many as 380 individuals
weighing about 50 kg. In Semporna,
farmers have employed night watches to prevent this problem. In addition to
improved security, farmers could cooperate and establish self-help groups as
features of future marine aquaculture zones.
Conflicts between farmers and fingerling suppliers
also arise due to the high mortality fingerlings. Farmers believe that the
fingerlings were caught with sodium cyanide and the resulting mortality
translates to financial losses or lower profit margins.
Future Directions
Under the Master plan for Aquaculture
Development in Sabah, the following are the planned directions for the
sustainable growth of cage culture and live fish trade of coral reef fishes. These
measures are meant to address insufficient supply of fingerlings, overfishing
of juveniles, and destruction of coral reefs that were identified as constraints
and problems in the industry. The goal is the conservation of juveniles and
adults in the wild and the protection of the coral reef from further
destruction. These wide-ranging recommendations are:
Supply of fingerlings
The government has already
initiated research in breeding and development of hatchery production for
marine fishes. Breeding for seabass and snapper (L. argentimaculatus)
has been successful. More of these initiatives need to be conducted for the
coral reef fishes in order to address the problem of supply of fingerlings and
develop the marine cage farming industry in Sabah. In the medium term, a marine
hatchery should be established in Semporna. This district is recommended
because of the abundance of suitable sites for holding broodstock, diversity of
fishes, and has good water quality.
Conservation of
Juveniles, Adults, and the Coral Reefs
Several measures were recommended under the
Masterplan to conserve juveniles, adults, and the coral reef environment. These
include:
a.
assessment
of the potential (sustainable) yields of live fish from coastal areas and
limitations on target fishing;
b.
exploration
of the establishment of marine protected areas with restrictions on live
fishes;
c.
restriction
of export of certain endangered species (e. g., Napoleon wrasse);
d.
promotion
of the involvement of the community in the management of fishery resources; and
e.
awareness-building
on sustainable fisheries exploitation and management practices
Conclusion
The cage culture of
coral reef fishes and other marine fishes in Sabah generates economic returns
for the industry. The commercial holding-type farms but not the small-scale
cultivating-type cage farms realise the profit in the cage culture and trading
of live fishes. The low productivity of the small-scale cage farms is largely
due to the insufficient supply of fingerlings to stock and maximise the use of
the cages. This constraint can be addressed by developing breeding and hatchery
facilities for coral reef fishes and other marine fishes. This solution is
recommended in conjunction with the protection of coral reefs from further
destructive fishing practices and with the management of utilisation of
populations from further overexploitation.
Acknowledgement
The paper is based on the Masterplan for Aquaculture Development in Sabah (MAL/93/013) developed by the Network of Aquaculture Centres in Asia-Pacific and the Department of Fisheries Sabah. The authors are grateful for the assistance of many farmers, government officials, and other individuals who contributed information to the study and guidance in the overall preparation of the Aquaculture Masterplan.
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