Marine
Fish Culture in Vietnam
Dao
Manh Son[1]
Abstract
Vietnam has natural conditions favourable for
marine fish culture with a 3,260-km coastline and a large exclusive economic
zone of about 1,000,000 km2.
Marine fish culture in Vietnam commenced in the 1960s, however during
the subsequent 30 years, development has been slow. Since 1990, commercial floating net-cage, pen and cage culture
has expanded considerably with an annual production of 30,000 tonnes. In recent years, considerable efforts have
been made to develop marine fish culture of grouper, snapper, yellowtail,
seabream, black kingfish, and wrasse.
Marketable size fish and fry are sold live to China, Hong Kong or Japan
by boat. Last year, more than 130
tonnes of grouper, snapper and seabream, and 450,000 yellowtail fry were
exported. Studies on the technology of
grow out culture and artificial breeding of some marine fish species are also
carried out. Some experiments on
artificial seed production of grouper, snapper and black kingfish were
successful, though survival rate is still very low. Despite marine fish culture having good potential for
development, there are various constraints to overcome.
Introduction
Vietnam has a coastline of
3,260 km, a large exclusive economic zone (EEZ) of about 1,000,000km2 and
more than 4,000 islands. These natural
conditions are favourable for mariculture, especially for marine fish, mollusc,
and seaweed farming. Marine fish
culture in Vietnam commenced in the 1960s with species such as mullet,
milkfish, and seabass. However, during
the subsequent 30 years, development has been slow. Since 1990, commercial floating net-cage, pen and cage culture
has improved considerably with an annual production of 30,000 tonnes. In recent years, considerable efforts have
been made to develop marine fish culture of grouper, snapper, yellowtail,
seabream and black kingfish. Some
initial successes have been achieved in creating a new aquaculture industry,
but certain constraints still remain.
Along coast of Vietnam,
there are many species that can be used for mariculture. The main species for floating net-cage
culture are grouper, snapper, seabream, yellowtail, kingfish, and wrasse. In pond, lagoon and pen culture, the main
species are seabass, milkfish, mullet, and Tilapia. The most highly valued species for culture
are the groupers; the most common species greasy grouper (Epinephelus
tauvina), E. bleekeri, E. areolatus, E. awoara, E.
moara, red-spotted grouper (E. akaara), E. fasciatus, E.
fuscoguttatus, E. malabaricus and humpback grouper (Cromileptes
altivelis).
Among them the red-spotted
grouper (E. akaara) and E. bleekeri command the highest price,
although other grouper species also have valuable potential markets. All 23 species of grouper found in
Vietnamese water are collected for export.
The
production of marine fish culture at present in Vietnam is very low. Every year, it is estimated that more than
130 tonnes of grouper, snapper, seabream and other minor fish and 500,000
yellowtail fry are exported. Separate
statistics for species are not available.
The total number of cages and production of marine fish culture in 1995
is shown in Table 1.
Table 1. Number of cages and production of fish
mariculture in Vietnam.
|
Province |
Number of cages |
Estimated production
(tonnes) |
|
Quang
Ninh |
126 |
40.0 |
|
Hai
Phong |
130 |
30.0 |
|
Thua
Thien - Hue |
120 (bamboo cage) |
8.0 |
|
Da
Nang |
130 |
5.0 (450,000 yellowtail) |
|
Nha
Trang |
60 (stationary cage) |
25.0 |
|
Binh
Thuan - Kien Giang |
70 |
15.0 |
|
Total |
636 cages |
123.0 |
The two main types of marine
fish culture practised in Vietnam are fry/fish holding and fry/fish
growing. The former is the main type of
production throughout the country.
Marketable-sized fish or fry are bought from fishermen, who use hooks,
long line, traps, purse seines or trawls.
The fish are then kept for between one week and two months before being
sold live to middleman or Hong Kong buyers.
Only three provinces (Quang Ninh, Thua Thien-Hue and Nha Trang) have
some facilities for grow-out culture, but the culture techniques are very
simple. In these areas, fingerlings of
10-18 cm are stocked at about 50-60 pieces/m3. Trash fish are used for feed at about 5-10%
of body weight per day. Cages are of
simple design with a frame system made of hard wood planks either tied or
bolted together, and kept afloat by simple 200 litre plastic drums or styrofoam
covered by a woven plastic cloth. The
single cage units are 2x2x2m3, 3x3x3m3 or 4.5x4.5x4.5m3
and are made of knotless netting.
Bamboo cages are used in Thua Thien-Hue.
Of the approximately 3,260
km coastal region, at least 1,200 km is estimated as suitable for cage farming
of marine fish species. The most
suitable areas are Ha Long Bay at Quang Ninh, around Cat Ba Island at Hai
Phong, Tam Giang-Cau Hai lagoon at Thua Thien-Hue, Son Tra peninsula at Da
Nang, and in Cam Ranh and Nha Trang bays.
The marketing channels for
aquaculture products are varied. The
majority of live fish and fry are transported by boat to China, Hong Kong and
to Japan (in the case of yellowtail).
The prices for different grouper species of live fish at marketable-
sized (400-1500g) range from US$8 to US$18 per kg. The prices for live seabass and snapper with the size of 1 to 3
kg ranges from US$5 to 7 per kg. The
prices for frozen fillets of seabass and grouper are US$8 to 10 per kg, for red
snapper and red seabream are US$3.5 and US$7 per kg, respectively. The prices of grouper fry range from US$0.3
to 2 per piece depending on size and season.
Groupers are considered the species with the most potential for marine
aquaculture in the region, because the species is highly valued and has a large
potential market.
Coral reefs in Vietnam are
mainly found south of the Quy Nhon in the form of near-shore coral reefs, and
as larger and deeper offshore reefs around the Hoang Sa (Paracel), Truong Sa
(Spratly) and Son Tu Tay in the Spratly islands. According to Yet (1994), there are 76 genera and over 298 species
of corals, some of which are threatened.
Extensive areas of coral around Cat Ba island have been degraded by
siltation caused by watershed changes, and most near-shore corals are thought
to be heavily exploited for various purposes including coral mining for lime
and fishing, in some cases using dynamite and other destructive fishing method.
Corals also provide inputs
to certain aquaculture system, particularly lobster (as around Nha Trang) and
marine fish cage culture. Degraded
reefs may be suitable for culture of Eucheuma seaweed, as is practised
in some other countries of the region.
According to available data, there are about 123 genera and 327 coral
reef fish species in the Spratly islands area.
The main species are wrasses (17.98%), butterflyfishes (7.92%), groupers
and snappers (5.48%), soldierfishes (4.26%), moray eels (2.35%), pipefishes and
other species. Coral reef fish
resources are exploited mainly as food fish.
Ornamental and aquarium fishes are hunted at a low level, so the
resources are still very abundant.
Until now, no detailed data on coral reef fisheries are available.
Although there are more than
450 fish hatcheries in Vietnam, all are for freshwater species. For marine fish culture, almost all fry are
collected from the wild. The availability
of fry varies greatly from year to year making it difficult or impossible for
farmers to fully utilise their cages.
Northern region
(from Quang Ninh to Ha Tinh)
In Hai Phong and Quang Ninh
provinces, the marine fish farming industry started in 1989. The highest annual catch of 500,000 fry was
in 1991. The mean annual catch is estimated
at 300,000 pieces. Groupers comprise
about half of the catch, with the rest split between seabream, snapper (20%),
seabass, and Bostrichthys sinensis (30%). In 1992, 300,000 red seabream fry were caught in the northern Ha
Long Bay, but the next year only 7,000 pieces were caught. The fry catching period is from March to
July (main season in April and May). In
recent years the seed supply in this region has decreased considerably,
especially around Cat Ba Island.
Central region
(from Quang Binh to Khanh Hoa)
Yellowtail fry are caught
between November and March with a peak in January and February. The maximum amount of fry caught in this
area is between 80,000 and 100,000 pieces annually. Landings of fry in 1991/1992 and 1992/1993 were 83,000 and 37,000
pieces respectively. Red-spotted
grouper (E. akaara) and greasy grouper (E. tauvina) are the most
common species in the Nha Trang area and more than 100,000 fry are caught each
year. Also seabass (Lates calcarifer)
fry are freely available as it is considered a pest in the lagoons used for
extensive shrimp farming. In the Cam
Ranh Bay (south of Nha Trang), fishers can catch 10 to 15 kg per day of grouper
fry with an average size of 70 g/piece.
The main catching season is from March to August, although fry are
caught year-round.
No data are
available regarding the potential catch from Ninh Thuan to Kien Giang province
in the southern part of Vietnam.
Throughout Vietnam, fry
catching methods are very simple.
Normally, fishers use hooks, longlines, traps, push-nets and trawls to
collect grouper and snapper fry. In
case of seabream and yellowtail they are normally caught using a beach seine or
lift net. The supply of marine seed
will limit the growth of marine fish cage culture in Vietnam. The technology is not yet available for the
artificial propagation of grouper, mudcrab, and lobster on a commercial scale,
although research continues at Cat Ba island and in other countries. In the meantime, the farming of these
species is dependent on wild stocks.
Fisheries for the seed of high value marine fish are not adequately
monitored or controlled. In the absence
of controls, stocks may be over-fished, with severe implications for the
environment and sustainable development of the industry. Under these circumstances it is difficult to
recommend expansion of these enterprises prior to proper assessment of impacts
and sustainable yield.
Since 1993, the Research
Institute of Marine Products (RIMP) of the Ministry of Fisheries has carried
out some experiments on artificial seed production of marine fish. Grouper, snapper and black kingfish (Rachycentron
canadum) were bred in 1994 and 1995.
The hatching rate ranged from 40 to 85%, but survival rate of fry was
too low (under 1%). The results of the
larval rearing during 1995 are shown in Table 2.
Table 2. Grouper larvae rearing results from RIMP
research during 1995
Date
|
Number of larvae |
Avg temp (ToC) |
Avg salinity (o/oo) |
Survival time (days) |
|
04/28 05/01 05/02 05/03 05/07 05/09 05/10 05/11 05/21 05/22 05/29 05/31 06/04 06/07 06/12 06/20 06/21 |
234,000 17,000 19,000 64,000 20,000 13,000 86,000 349,000 147,000 57,000 245,000 201,000 26,000 12,000 6,000 50 89,000 |
28.0 29.0 30,0 30.0 27,0 27.2 27.8 28.0 28.5 29.5 31.0 31.5 30.5 30.0 27.5 30.0 32.0 |
30 30 30 30 31 32 31 31 32 32 32 31 31 31 30 30 30 |
60 4 14 3 2 7 9 8 12 6 6 7 60 3 2 1 5 |
|
|
1,584,000 |
|
|
|
Larvae were fed 4 times a
day on oyster eggs, rotifer and Artemia depending on the stage of
larvae. The studies on artificial seed
production of grouper, snapper and black kingfish have been initially
successful, however, many technical problems in the early stage of larvae
rearing must be solved. A marine fish hatchery,
which should commence operation in 1997, is under construction in Cat Ba
Island.
Trash fish
and prepared feed are the main food sources used for grow-out. In the southern and central part of Vietnam,
there are 24 feed production units with total capacity of 47,000 tonnes per
year for shrimp and brackish water fish culture. SEAPRODEX Da Nang has a pelleted feed producing plant with a
capacity of 2,000 tonnes per year. The
majority of the production is shrimp feed including two types: one for
semi-intensive farming in the central region and a small amount of high quality
feed for two intensive shrimp farms in the Mekong river delta. Until now, most feed used for marine fish
culture is “trash” fish. Only a small
amount of prepared feed, imported from Japan, is used for yellowtail fry raising
in the Da Nang area. At present in
Vietnam, capture fisheries provide about 800,000 tonnes of fish per year, of
which 200,000 tonnes or a little more are classified as low value trash fish.
Trash fish includes the
following fish species: spotted sardine (Sardinella jussieu), round scad
(Decapterus maruadsi), tiger fish (Therapon theraps), lizard fish
(Saurida spp.), commersonis (Stolephorus commersonii), pony
fishes (Leiognathus spp.) and the juveniles of a range of species,
including table fish species. Trash
fish is a common marine fish feed in Vietnam, particularly for cage-cultured
fish and for shrimp. The heavy use of
trash fish in ponds and cage culture can contribute to poor feed conversion and
can be highly self-polluting.
Food conversion ratios
(FCRs) for grouper in Vietnam range from 6 to 20:1 depending on the type of
feed and feeding regime. FCRs for
yellowtail fry are rather low, remaining between 2 and 3:1 because of the use
of commercial feed from Japan. In
general, cage farmers appear to have little experience in proper feed
management, resulting in poor food conversion.
Sustainable development of
coastal aquaculture in Vietnam requires that close attention be given to the
identification and control of shrimp and fish diseases. The high losses from shrimp disease can be
reduced by introduction of more effective health management practices. The potential economic and environmental
benefits provide strong justification for such measures. At present there are too few well-trained
scientists and technicians available for the research and development in shrimp
and fish disease control. Modern
diagnostic facilities are also generally lacking, particularly basic field
equipment which can be used at farm level to investigate disease outbreaks,
collect samples in a proper way and diagnose farm-level problems. The strengthening of human resources and
facilities requires urgent attention to deal with present and anticipated
future problems related to shrimp and fish disease. Environmental problems faced by farmers include losses due to
damage in exposed sites, and some water pollution problems, leading in Ha Long
Bay to some fish mortalities from localised water quality deterioration. Such problems can be avoided by selecting
locations with sufficient water change, and ensuring stocking levels and cage
numbers are within the capacity of the local environment.
There are risks under
present management systems of introducing new diseases to aquaculture
environments. The ordinance on the
"Conservation and Management of Marine Resources" states that
Ministry of Fisheries has the responsibility for decisions concerning the
introduction and breeding of new species in Vietnam. However, limited capacity exists to analyse and support such
decisions at the present time.
For stocking of cages, fish
fingerlings smaller than 10 cm are stocked at 70-80 pieces/m3 and
fish of 10-18 cm are stocked at about 50-60 pieces/m3. The bigger fish (>20cm) are kept with a
density of 30 pieces/m3.
From 1992 to 1995, RIMP has
carried out some studies on the technology of grow-out culture and artificial
breeding. The study results showed that
the growth rate of grouper, snapper and yellowtail reared in floating net cages
is rather good. The growth rate per
month for grouper is 60 to 80g, and for snapper and for yellowtail is 90 to
100g and 250 to 280g, respectively.
Kingfish in particular has a high growth rate of 300 to 400g/month. Seabass has been grown in ponds and their
growth rate is about 100 to 130g/month (seabass are fed live Tilapia
kept in the same ponds).
The exploitation of coral
reef fishes in Vietnam is not thought to be a big problem, because the coral
reef fisheries are relatively unexploited.
Only some ornamental fish companies carry out activities, collecting
high value fish by divers using SCUBA with traps, hooks or hand held scoopnet
at depths of 6 to 40 metres in the Nha Trang area and around the Spratly
archipelago. Some foreign joint
ventures use toxic sodium cyanide to catch fishes such as grouper, snapper,
wrasses and other fisheries, and some fishermen use illegal explosives for
fishing.
Cyanide affects far more
than just the target species. Smaller
fish and shellfish are less resistant to cyanide, and many die for each target
fish captured. Moreover, corals, which
provide the basic foundation of the reef community bleach and die.
There is little primary data
available on the environmental impacts of aquaculture in Vietnam. Research on the environmental impacts and
management of coastal aquaculture should be encouraged, in order to properly
define impacts and management protocols for different aquaculture systems and
coastal environments. Coastal
aquaculture should make environmentally sustainable use of land and water
resources, and be properly integrated into exiting agricultural and ecological
systems, such as agricultural farms, watersheds and coastal areas. To maximise the social and economic benefits
of aquaculture development in local communities and to avoid social conflict
and conserve natural resources, the process of aquaculture development must
carefully consider the needs of all resources users. Thus, local and national government should encourage and
facilitate participation of the public, communities and industry in formulating
policies and guidelines for aquaculture development, within the carrying
capacity of the coastal environment and in harmony with other local users of
common resources.
Effluent and water quality
standards for aquaculture and coastal areas should be viewed as medium to
longer-term objectives. The Ministry of
Fisheries should coordinate efforts with the Ministry of Science, Technology
and Environment, and other concerned agencies for a comprehensive coastal water
quality management scheme, to ensure a comprehensive coverage of coastal water
quality. The application of environment
impact assessment (EIA) can be used to guide environmentally sustainable
investment decisions. The regular
environmental monitoring of coastal areas can also help provide early warning
of any harmful environmental changes in aquaculture areas.
Grouper prices are currently
high, with an average domestic price of around US$10 per kg. Even this level is low by international
standards, and some increase may be obtainable through negotiation with Hong
Kong buyers. Farm size is variable,
ranging from small farms with 2-4 cages up to major enterprises with 60 or 100
cages. On an area basis, grouper
culture is estimated to produce gross revenue of the order of US$160 per m2
with total production and overhead costs amounting to about US$130 per m2. Margin is a relatively low 19 percent of
output, suggesting that the activity be at potential risk due to price or cost factors
or mortality. The main constraint
facing the activity at present is difficulty in obtaining fry in some areas and
some seasons. It is quite likely that
commercial hatchery technology will overcome its technical difficulties in the
next five years or so, which would assist in alleviating the seed
constraint. It is likely that the
development of hatchery technology will reduce the economic viability of
grouper farming. When the current
reliance on wild fry for stocking and trash fish for feed is taken into
account, it is not considered that substantial effort is merited by the
government to promote the development of grouper farming, without concurrent
investments in hatcheries and feeds.
The marketing channels for
aquaculture products are varied. Since
the introduction of market reform, entry to the marketing industry has been
more or less unrestricted. This has
resulted in a rapid increase in the number of middlemen servicing the
sector. While marketing systems and the
degree of competition will develop overtime, it is considered that the small
business skills of the Vietnamese represent strength to be capitalised on. Where any niche is identified in the
marketing and distribution chain, it is likely that it will be filled rapidly,
particularly if the entry capital needs are limited. At the same time, the government needs to monitor marketing and
to assist in removing market imperfections.
There are several major
constraints for the development of marine fish farming in Vietnam, most of
which can be traced to the lack of capital and knowledge related to marine fish
farming. There is a need for technology
related to the production of fry, as well as cage farming in the sea. So far the low availability of marine fish
fry has limited the development of marine fish farming. Both the variability and insufficient number
of wild caught fry will not sustain a long-term development of sea cage
farming. Without hatcheries and
nurseries, the scope for marine fish farming is limited. Also sea ranching to increase the natural
fish stocks by release of artificial produced fry depends upon stable supplies
of fry in high numbers.
Long term education and
training seem to be the most important factors for a sustainable development of
marine fish farming in Vietnam.
Development further implies the use of technology adapted to Vietnamese
conditions, and an optimal use of available resources for fish feed.
After the problem of fry, the availability and quality of
feed is regarded as the most serious constraint to the farming of marine
fish. At almost all fish farms, the
fish are fed daily when trash fish was available. The use of trash fish creates environmental problems, which has
probably led to some of the diseases encountered. To develop marine fish farming on an industrial scale, together
with usage of trash fish, it is necessary to have many fish meal units to
produce enough pelleted feed for aquaculture.
The other constraints for marine fish farming include:
·
lack
of planning of culture areas, which can result in potential ecological and
environmental problems
·
the
unsatisfactory development in the culture of export species, resulting in low
yields
·
limited
scientific research findings, especially in relation to artificial seed and
prepared feeds, to increase production
·
high
economic risk due to new technology; no insurance is available for farmers who
may lose their equity or working capital and be forced out of business or to
borrow from moneylenders at high interest rates
·
severe
storms and typhoons are a major constraint to coastal aquaculture in the north
and central part of Vietnam
·
lack
of fish disease diagnosis and treatment
The main recommendations
include:
·
Research
is essential to identify and help remove constraints to aquaculture development
in Vietnam. Research budgets are
currently inadequate to allow the institutions to operate effectively.
·
Long
term education and training for young scientific and technical staff are very
important in order to develop marine fish culture in Vietnam.
·
The
production of marine fish seed must be established both in quality and quantity
if the fish farming industry is to develop in a sustainable manner.
·
The
development of the coastal aquaculture sub-sector requires the clear,
well-formulated, and implementable national and local policies and is based on
a full consideration of financial, socio-economic, and environmental
sustainability.
·
Research
institutes and University should be encouraged to establish links with other
regional institutes involved in coastal aquaculture research, as there is much
relevant research work going on which would be useful to Vietnamese scientists. Such cooperation, possible through the
Network of Aquaculture Centres in Asia- Pacific (NACA) and other regional
organisations, would be cost-effective for Vietnam, and would help avoid
repeating research.
·
The
introduction of technologies to Vietnam should be undertaken with care, ensuring
compatibility with local environments and farming systems.
References
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Direction and objectives for Vietnam fisheries development during
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Son, D. M., 1995. Floating net
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presented at the training course on fisheries extension activities, Hai Phong,
August 1995. 8pp.
Son, D. M., 1995. The technical
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of grouper, snapper and yellowtail.
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Son, D. M. and
T.V. Quynh, 1995. The present status and future prospects of
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C. S. Lee (ed.) Status,
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Fisheries, Hanoi.
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