FFRC Annual Report 1996
Foreward
One of the major aim of the center
was to continue to excel in its research activities in meeting the immediate and relevant
needs of the freshwater fisheries industry of Malaysia. This year's research programmes
were to enhance the production of high valued food fish and the high revenue earning
aquarium fish and aquatic plants by either improving the existing farming systems
management or through the introduction of new intensive systems.
Research for the year therefore has
been concentrating on the breeding come growout culture systems and their management with
particular emphasis on the high valued indigenous fish species including the Temoleh (Probarbus
julienii), Baung (Mystus nemurus) and Haruan (Channa striatus).
Particular emphasis was given on broodstock management in tanks in anticipation of the
future development whence earthened ponds become more expensive due to the escalating
land's cost. The system designed for the broodstocks is anticipated to replace the earthen
ponds. The system has taken into consideration factors such as the optimal use of space,
water saving facilities and effective control against disease and malnutrition. Genetic
works on Tilapia was continued giving priority to developing alternative strains with high
flesh production for filleting. In the aquarium fish scenario, Arowana was given the
highest priority in view of the success achieved by the private sectors to breed the fish
naturally but in captivity. As for the aquatic plants a number of trials were conducted to
propagate the plant via the tissue culture technique while at the same time to establish
optimal planting techniques and management using tanks. The Fish Health and Disease
Treatment Section has also made some progress in the effort to produce fish vaccine when
it developed the first vaccine using the toxin produced by Vibrio anguillarium with the
help of Swedish University of Agricultural Sciences, Uppsala, Sweden.
Altogether fourteen projects were
implemented in 1996 and were funded through the Intensification of Research Priority Areas
(IRPA) programmes. The total sum received from the programme for the fiscal year was RM
670,450.00. Apart from this, one project was funded by the Agriculture Ministry (SEO) and
another two research projects were supported by the development fund obtained from the
Extension and Training Division of the Department of Fisheries.
Hambal b. Hj. Hanafi
Chief of Centre,
Freshwater Fisheries Research Centre,
Batu Berendam,
Melaka
INTRODUCTION
THE CENTRE
The Freshwater Fisheries Research Centre
(FFRC) is one of the six centres that come under the Fisheries Research Institute (FRI),
Batu Maung, Penang. It is the only research centre in the Department of Fisheries Malaysia
that specifically conducts research studies on Freshwater Aquaculture and Inland
Fisheries. The principal on-going research programmes of the centre are Fish Breeding
& Genetics, Aquarium Fish & Aquatic Plants Propagation, Fish Culture &
Nutrition, Fish Health (both monitoring and prevention), Inland Fisheries and Aquaculture
Engineering.
The total number of staffs in
the centre is 96 comprising of 14 Research Officers, 8 Research Assistants and 18
Laboratory Assistants. The remainder comprises of 21 Administrative Staffs and 35
supporting staffs. The centre is also maintaining a Swedish expert counterpart to help in
the fish disease research. Besides being responsible for their research works, the
officers were also involved in providing expertise, conducting lectures for both the
department's staffs and target groups and also hamds-on training to some farmers at the
center.Most of the research operating funds originated from government's funding under the
Intensification of Research Priority Areas (IRPA) which had amounted to RM 670,450.00 and
another RM97,000.00 sourced from the Minisrtry of Agriculture for the Socio Economic
Studies for the year. The total development budget for the same year was RM 220,000.00 and
was mainly meant for the construction of the Aquarium Fish and Aquatic Plants' Research
Complex. A total sum of RM 2.01 million was spent for administrative purposes. Utilisation
of manhour and funding of the center are depicetd in Appendix I and Appendix II.
RESEARCH DIRECTION AND THRUST
The research activities of the center are
formulated in line with the government's policy and the Department of Fisheries' target to
increase the nation's fish production through aquaculture and inland fisheries while being
guided by the IRPA's panel.
Research programmes in propagation and seed production area
concentrated on the development of protocols for the mass production of commercially
important indigenous carps and ornamental fish. In addition, research was also directed at
refining the existing seed production technology of some species. However, the major focal
points of the research in this area were broodstock development and spawning protocols of
a few targetted indigenous species.
Fish Growout research during the year focused on enhancing
production through non-traditional production systems such as tanks. Hence there is a need
to develop cost effective filter systems for these commercial scale tank culture.systems.
The system's design was also investigated, especially in relation to the behaviour of the
selected fish species.This approach was taken in anticipation of future shortages in land
and water resources. There is also a need to develop suitable cage designs that are labour
efficient and to establish their management regimes that can minimised negative
environmental impacts.
The thrust of biotechnology research was in the tissue
culture of aquatic plants, production of microalgae for aquatic seed production and
genetic enhancement of major cultured finfish. The tissue culture research program will
have a significant impact on the aquarium trade, where the country is presently a major
player, while the second would be of application in seed production at the hatchery level.
Genetic enhancement, on the other hand, would enable the efficient production of high
quality fish both for local and export markets.
The main thrust of research by the Inland Fisheries section
was the monitoring of fish catch by inland fishermen for the fisheries management and the
modeling simulations of recreational fishing catch of the Kenyir Reservoir in Terengganu.
There is currently a riverine fish rehabilitation study being undertaken in Klang River in
Kuala Lumpur. This program, which was started in 1990, is expected to end in the year
2000.
RESEARCH
ACHIEVEMENTS - IN BRIEF
Among the research projects that were carried out, some
have achieved results that are of significant importance to the development of the
freshwater fish industry. These are described briefly in the following paragraphs.
The Fish Breeding Section experimenting with the
broodstocks of Haruan Channa striatus, Baung Mystus nemurus and Temoleh Probarbus
julienni maintained in tanks and fed with 35% protein formulated diet has also
made some progress. The females of Baung and Haruan each averaging 600-700 and 400- 500
grams in weight respectively were successfully induced to spawn using 0.5ml/kilogram
Ovaprim and 5000IU/kilogram of HCG in the latter. While the males of the same weights
respectively were induced using half of the doses. Larval rearing and nursery of the
offsprings has resulted in an average of 60% survival rates. For the year, the Temoleh
female spawners maintained in the tanks had not indicated that they were ready to spawn
even though the males were detected to be ready.
Effort to produce Tilapias which have greater flesh weight
per millimetre of standard length by the Genetic Section has been fruitful. Results
indicated that the resulting fry showed a 47.15% improvement in terms of overall body
conformation besides better growth rate of not less than 3 grams per day.
Experimentation on immunisation of antibody towards A.hydrophila
by the Fish Health and Disease Control Section gave positive results in chicken
eggs. The egg yolk mixed with formulated feed when fed to catfish fry had resulted in
better overall growth performance and healthier looking fish.
Attempts to breed the popular Harlequin Rasbora
heteromorpha by the Aquarium Fish and Aquatic Plants Section has also been
successful after an intensive study of their behaviour while in captivity.
The Tissue Culture Section has been successful in
propagating the Cryptocoryne sp. stem section as the explant tissue in the MS
nutrient medium. The plants grew best using the combination of 0.1ml 2-4D+2ml BAP+8 mg
agar.
PHYSICAL FACILITIES
The facilities available for research works, both at
laboratory and pilot scale, have been added on from time to time along with the present
research needs and present development.
Facilities Availablle for
Finfish Breeding
A hatchery that is equipped with 4 units of 20 tons
circular broodstocksand spawning tanks, and 10 units of (2 ton) larval rearing tanks.and
30 units of 0.4 ton meant for rearing the yolked larvae and other research studies.
A semi-automated closed rain water recirculation system
which is equipped with water and aeration pumps. The facility is also equipped with 4
units of 25 tons circular tanks for fish rearing.
92 earthen ponds of various sizes designed for rearing
broodstocks, nursing the jouveniles and growout.
A wet laboratory which houses the induced breeding tanks
and equipped with tissue homogenizer, centrifuge, electronic balances, nets and hormones.
Laboratory Facilities for
Histology Studies
The histology laboratory had been
revived to support on-going research works especially those concerning broodstocks
maintainance and breeding works. The lab has been equipped with basic histology laboratory
equipments including the Cell Processing Unit, Microtome, Staining unit, Cell warmer and
wax dispenser. A well trained and experienced Research Assistant is currently in charged
of the lab.
Laboratory Facilities for
Aquatic Plants Tissue Culture Studies
This area is equipped with the facilities for sterilisation
works, media preparatory space equipped with a distillation unit, electronic balance and
electric stirrer, the transfer room equipped with two units laminar flow and finally the
culture room which has been spefically designed for 24 hrs lighting and an almost sterile
environment.
In the meantime the section was also looking into
constructing a greenhouse for pilot scale planting experiment.
Laboratory Facilities for
Nutritional Studies
The laboratory has been equipped with sufficient equipment
to conduct proximate analysis of the crude protein, fat, carbohydrate, crude fibre and ash
plus tank systems for the digestibility study.
Wet Laboratory Facilities for
Aquarium Fish Breeding
A new building has been constructed within the office
complex to provide the on-going research with better laboratory facilities and working
environment. Even then the old wet lab located in the pond complex is still maintained.
There are now more than 100 aquarium tanks of various make and shapes with a few specially
designed tanks for research in particular spawning and breeding.
A General Laboratory for Soil
and Water Chemistry
This laboratory is equipped to carry out both quantitative
and qualitative tests on soils and water. Portable water and soil analysis kits are also
available for basic field tests.
Laboratory Facilities for
Fish Health Management
The Fish Health Section has a General Laboratory equipped
with autoclaves, incubators, freezer (-80C), cooling cabinets,
spectrophotometer, microscopes and complemented with surgical and clinical facilities for
fish and other aquatic life disease diagnosis especially for those of parasital and
bacterial origin. A set of electrophoresis equipment was acquired for the purpose of
protein profiling of Aeromonas hydrophila strains selected for the study. Recently
the laboratory has aquired an Elisa reader enabling them to check on the titre antibody
serum for the determination of the effect of the application of an antigen. A desk top PC
together with a printer were also bought to keep all relevant data and carry out
experimental data analysis important to the study.
FUTURE DIRECTION
The center will continue to conduct research programmes in
line with the government policy and in particular the needs of the industry at the time.
It is hoped that it will be able to pioneer the latest developments in freshwater
fisheries and establish new and economically viable technology that are optimally suitable
with the local climatic conditions and social status of Malaysians. These new technologies
will have to be duely proven to be both economically viable and environmentally safe
before disseminating them to the target groups. The new technology developed will ensure
the fish protein needs of the nation is met and that they are able to compete economically
with fish products produced in other countries.
With the competency attained over the years the center
should be able to propel the freshwater fisheries industry towards a more efficient
producer of white meat through the harnessing of the scientific knowledge and
technological innovations achieved by the researchers.
The mission of this center is to be a catalyst
in the commercialisation of these technological innovations so as to increase the food
supply and revenue to the nation.
RESEARCH
Research Output
PROPOGATION AND SEED PRODUCTION
Induced breeding of Temoleh (Probarbus
jullieni) Using Ovaprim
During the year, fifteen female breeders were injected with
Ovaprim (Fig 8) in ten induced breeding trials. The latent period from the injection to
stripping of the fish was 10 hours at 25.50 Celsius. Fertilisation rates ranged
from 90-95% while hatching rates averaged 90-95%. It was observed that Ovaprim injected
fish produced healthier with fewer deformities offsprings as compared to those produced
using HCG and CPE.
Induced Breeding of Kelah (Tor
tambroides) Using Ovaprim
Only one induced spawning trial was able to be conducted
this year. The female fish was injected with 0.5ml/kg of Ovaprim (Fig 9) and the males
received 0.3ml/kilograms fish weight of Ovaprim. However, the attempt was unsuccessful,
possibly due to an insufficient dosage of the hormone utilised.
Induced Breeding of Tengalan (Puntius
bulu)
This was a new project and no induced breeding trials have
been conducted. Much of the time have been spent in procuring the broodstocks (Fig 10)
from Tasik Temenggor and which were later stocked in the ponds. Monthly samplings were
conducted to assess the stages of gonadal maturation. Though milting males were observed,
none of the females had reached the tertiary maturation.
Broodstock Management of
Temoleh (Probarbus jullieni) In Circular Fibreglass Tanks
The experiment involved a total of 25 F1 broodfish
comprising of 15 females and 10 males. They were maintained in the Rainfed Recirculated
Fish Culture System (Fig.11) throughout the trial. Data from monthly samplings indicated
growth rates as high as 1.5kilogram/year. Milting males have been detected. However,
though early signs of sexual maturity were detected in the females, none had yet reached
the tertiary level of maturation.
Larval Rearing of Temoleh (Probarbus
jullieni) In Fibreglass Tanks
This study was directed to preempt the high mortalities
when fish larvae are reared in earthen ponds (Fig.12). In this technique, newly hatched
larvae were innitially nursed in holding trays for 4 days till they fully absorbed in the
yolk sacs. The larvae were then fed with chicken egg yolk, formulated eel-feed and live
feed consisting mainly of Rotifers and Artemia for a further 6 days. They were then
transferred to the 2-tons fibreglass tanks (Fig. 13) and reared until they have reached a
size of 3-5 centimetres, at which point they were transferred to the earthened ponds. A
good survival of 75-85% was able to be maintained through this technique as compared to
less than 30% obtained through the traditional practice.
Managing Broodfish of the
Catfish, Baung (Mystus nemurus), in Tanks/Cages
Baung (Mystus nemurus) broodstock were stocked in
the 20-tons circular fibreglass tanks in the Rainfed Recirculating Fish Culture System.
Feeding was provided daily with a formulated pellet feed containing 32% crude protein.
Monthly samplings were carried out to monitor their growth and gonadal maturation.
Spawning was induced using Ovaprim at a rate of
0.5ml/kilogram of fish for the female and half of that dosage was used for the males. The
hormone was administered in a single injection dorsally. The eggs were stripped 14 hours
later. Fertilised eggs were incubated in trays immersed in the 2-0 tons fibreglass tanks
supplied with vigorous aeration. Hatching occurred after 28-32 hours. Larval rearing was
undertaken in the 2-tons fibreglass tanks. The fish larvae were only fed from the third
day after hatching. Artemia or Moina was given during the first month after
which 35% protein mash was given.
In-Situ Induced Breeding
of the Catfish, Baung (Mystus nemurus), On Floating Hatchery Using 'Wild'
Broodstock
Matured wild stock of Baung (Fig. 14) from Tasik Kenyir
were purchased from local fisherman and kept in 10' x 10' x 6' floating cages (Fig. 15)
and fed with floating pellets (3% Body Weight per Day) and trash fish (1x/week). Female
and male were isolated in separate cages to inhibit possible natural breeding. After 3
months, the broodfish were checked for maturation by squeezing the abdomen. Fish with
oozing eggs were chosen for the induced breeding trials. The first induced breeding trial
was successfully undertaken in September 1996 i.e. coinciding with the natural spawning
season of the wild fish in the lake. The hatching rate was estimated 40% and produced
10,000 fry. Further work is needed to verify if the fish would spawn throughout the year
as is at the research center in Batu Berendam and the larval rearing could be carried out
in the floating hapas installed on the floating hatchery.
In-Situ Nursery Management of the Catfish. Baung (Mystus nemurus) Fry In Cages
Studies on the nursery management of 2.5 centimeter sized
fry in nursery cages resulted in a survival of 70% using commercial floating pellets with
a 32% crude protein level. However, at high stocking densities of 2,000 per cage led to
cannibalistic behaviour and resulting in injuries especially in the caudal fin area that
resulted in the high mortality observed. It is observed that the practice of feeding to
satiation would result in better survival.
Mass Production of the Snakehead (Channa
striata)
Broodstock of the Snakehead, (Channa striata), were
stocked in 50 centimeter deep water in 3 meter x 3 meter concrete tanks (Fig. 16). Feeding
was provided twice daily with formulated mash having a minimum crude protein content of
35%. The sexes were differentiated by inserting a catheter in the genital pore. For
females, the optimal depth of insertion was found to be about 1.5 cm. Spawning was induced
by injecting dorsally HCG at a dosage of 5000 I.U./kilogram of fish for the females, and
half that for males. After 24 hours, spawning occurred through natural oviposition. The
eggs hatched out after a further 24 hours. Ovaprim at 0.5 ml/kg for females and 0.3ml/kg
for males also succeeded in induce spawning. However, the eggs did not hatch. Larval
rearing was undertaken in fibreglass tanks. Larvae were fed from the third day after
hatching. Artemia or Moina was given during the first month, and 35%
protein mash was given from the 2nd month onwards.
Breeding Of Malaysian Golden Arowana (Scleropages
formosus)
Golden Arowana broodfish were first obtained from a
collector in Alor Pongsu, Perak in 1990 and were reared in a 5.0 x 5.0 x 1.5 meter
concrete tank with a 'hide' built into one of its corners, Fig. 17. Water pH was
maintained between 6.8 - 7.5 and temperature between 27-29 Centigrade. Live feed such as
crickets, wild guppies, freshwater prawn (Macrobrachium lanchesteri) and 'low
value' goldfish (Carassius auratus) were given twice daily. In the year 1996, there
were only 7 pieces aged 6 years left in the tank. The monthly samplings were stopped to
avoid disturbing the fish. During the first 5 months of 1996, the fish did not show any
gonadal development. On May 18th, however, two 'brooding males' were detected
in the tanks. They were identified by the extended operculum and slightly protruding lower
jaw.
On the 18th day after the detection, the two brooders were caught to
remove the fertilised eggs from the mouth. No eggs were found in one of the males possibly
because the eggs were swallowed by the male broodfish. Fourteen (14) fertilised eggs were
successfully extruded from the other male broodfish (Fig. 18). Embryo of sized 15
millimeter were observed at one side of the each egg. The fertilised eggs were incubated
artificially in a 0.3 x 0.3 x 0.3 meter glass aquarium at the temperature of 28
Centigrade. Unfortunately the eggs burst and the embryo collapsed within three days.
Breeding of the Harlequin rasbora (Rasbora
heteromorpha)
Observations of the Harlequin rasbora (Rasbora
heteromorpha), Fig. 19, indicated that the fish prefer to swim in schools and can
attain a length of about 2.5 centimeter in the wild whereas about 3.0-3.5 centimeter in
captivity. Captive specimens reached maturity in 8-12 months depending on environment and
diet.
Broodfish were stocked in 1.0 x 0.5 x 0.5 meter glass
aquaria filled with rain water containing peat moss which had been soaked previously for
1-2 weeks. The aquaria was densely planted with broad leaf aquatic plants such the Amazon
sword plant (Cryptocoryne sp.), Fig. 20. The water became slightly
brownish in colour with a hardness of 50-80ppm and pH of 6.5-6.8. Spawning occurred within
3 days with the eggs being deposited mainly on the underside of leaves of the Amazon sword
plants. One week after the fertilization, the free swimming fish larvae were observed. At
this stage the larvae were fed with newly hatched Cyclops and brine shrimp. After a
further 7 days they were replaced with Moina sp.. After one month,
the fry had attained a size of 1.0-1.5 centimeter and exhibited the distinct dark blue
black triangle at the caudal peduncle the distinct characteristic of the species.
GROW-OUT
The Development of Cage Culture
Technology Using Improved Cage Design Utilising Mystus nemurus and Its Impact
on the Environment
A new cage design was developed that enable it to be
automatically tilted above the water level for easy management, sampling and harvesting,
Fig. 21. The culture of 1,000 fish per cage of 3 meter X 3 meter X 2 meter resulted in
high mortality and injury to the fish, mainly due to the lack of feed. However, the growth
rate of fish fed with commercial feed has been disappointing compared to farmers who use
trash fish or chicken viscera. After more than 6 months in culture cages the average size
were only 250 grams. This was probably due to the low fat content in the formulated feed.
The growth rate can probably be improved further by increasing the feeding frequency or by
increasing the fat content in the diet. Trash fish and chicken viscera were not used so as
to avoid water quality problems. Preliminary observations of some water quality parameters
around the cage area have shown no significant changes although 1.5 tons of the commercial
formulated feed were utilised every month. This can be attributed to either the depth of
the water body where the cages are located or to the water currents where the nutrients
are flushed away and diluted.
Preliminary Observations on the Use of
Hydrilla as Sediment Trap in Recirculating Fish Culture Systems in Tanks
Preliminary observations indicate that the macrophyte, Hydrilla
sp. Fig. 22, cannot serve as an effective filter to remove suspended materials which
were mainly in the form of fish faeces and excess food in the recirculating systems, Fig.
23. The plants were found to wilt from the first week of planting, and almost all were
dead by the end of the second week. In addition, the decomposing dead plants parts in the
system also added-up to the sediment load within the tank.
Preliminary Observations on the
Use of the Macrophyte Eichhornia sp. as A Sediment Trap in Recirculating Fish
Culture Systems in Tanks
Preliminary observations have indicated that the macrophyte
Eichhornia sp. , Fig. 24, was unsuitable for use as a sediment trap in the
recirculating fish culture systems. The plant generated short rooting system that were
frequently replaced. The broken roots increased the sediment and nutrient load in the
culture system.
Preliminary Observations on the
Use of Plastic Sheets placed at 45o as A Sediment Trap In Recirculating Fish
Culture Systems
The study has indicated that the use of plastic sheets at
45o Fig. 25, was ineffective in filtering out the sediment from the
recirculating fish culture systems.
Preliminary Observations on the
Use of PVC pipes as A Sediment Trap in Recirculating Fish Culture Systems
Short lengths of polypipes (diameter 4", length 4')
arranged vertically in the tank were found ineffective to filter sediment in recirculating
fish culture systems.
Preliminary Observations
on the Use of Gravel as Trickle Filter to Eliminate Ammonia in Recirculating Fish Culture
Systems in Tanks
The studies carried out indicated that trickle filters
consisting of gravel packed in plastic cylinders (height 54cm; diameter 40cm; volume 68
litres) is effective in reducing ammonia by about 15%. The filter begins as an effective
ammonia remover about 7 days after commission and reaches its peak efficiency after about
21 days. At this point, the filter is able to remove 13-18ppm of ammonia daily.
INLAND FISHERIES
Fish landing data from the Kenyir Lake
fishermen
The fish landing data came mainly from the fishermen at
Jenagor and only limited input from Gawi, Map 1. The data was collected 2 times per week
from Jenagor and once per week at Gawi. Data collected include species, amount (both
number and weight) caught and their morphological characteristics such as total length and
weight.
In 1996, total catch amounted to 37.3 MT of which Lampam
Sungai constituted 53.4% (by weight), followed by Toman (18.5%) and Baung (16.5%). Baung
catch reduced by 7% whereas that of the Toman increased by 6% compared to the 1995
landing. The results are shown in Graph 1. There was not much change in term of active
fishermen numbers, type of gear used, location of catches and species caught in 1996. The
monthly total catch is shown in Table 1.
Recreational Fishery-Modelling
simulation of reservoir fish community
A total of 5 fishing trips were conducted in 1996 using gillnets with 10 different
mesh sizes, from 25mm to 150mm. The netting was done parallel to the shore. The water
quality were analysed and the water levels were also recorded. All data were stored in a
relational database. The main fish species caught were Lampam Sungai, Toman, Baung and
Sebarau. Initial analysis
of the data showed that the biomass of the fish population
was mainly attributed to the Lampam Sungai, an omnivorous species. The main carnivorous
species, Sebarau, constitute the least biomass to the population sampled. Higher total
biomass was observed during the rainy months (Oct-Nov). There was no significant
difference in the water quality except turbidity, which was higher during the rainy
season. With respect to fecundity patterns, preliminary results indicate that Lampam
Sungai has an absolute fecundity ranging from 46,354-150,045 and a relative fecundity of
405-502 from sizes ranging from 21.5-28cm. The following bar graph (Graph 2) shows that
the fecundity is proportional to the length class of the fish i.e. Lampam Sungai. Based on
the present data the elaborate conclusion is not possible because there are other factors
affecting the gonadal development.
Beautification of Sungai Kelang
Eight locations along the river were selected as the
monthly sampling points. Analysis indicated increasing deterioration of water quality
downstream. The dissolved oxygen, for instance, decreased from 6 ppm at the upper end to
more than 2 ppm at the last sampling point. The biological oxygen demand showed a similar
trend with higher readings at the lower downstream. The total number of fish species also
decreased down river. Cyprinids were found in the upper reaches while only hardy species
such as the Tilapias were found downstream. Released fish, such as Puntius gonionotus,
Mystus nemurus and Macrobrachium rosenbergii were not at all
present in the monthly samplings carried out.
BIOTECHNOLOGY
Tissue culture of aquatic plants
Efforts were continued towards propagating endemic aquatic
plants viz. the Cryptocoryne sp. , Fig. 26, by tissue culture. Several new and
different species of plant that were available at the centre were also investigated, using
Murashige and Skogg (MS) and Linsmaeir-Skogg (L-S) basal medium with different combination
of Auxin and Cytokinin hormones. Success was attained for Cryptocoryne sp.,
(Fig. 27). The explant tissue, used for the propagation, was the stem section. The
explants were first sterilised in mercury chloride, alcohol and Sodium hypochloride
solution of known concentration before culturing in MS nutrient medium. The growing
tissues were then transferred to a new medium every two or three weeks. The culture tubes
were kept in the laboratory at a temperature of about 25oC and grown under
24hrs fluorescent lighting. The plants grew best using a combination of 1 ml 2-4D + 2 ml
BAP + 8 mg agar.
Production of live food
Mass production of
(Daphnia magna)
Work was continued on the culture of the exotic Daphnia
magna (Fig.28). Culture trials were now conducted in 2-ton fibreglass tanks
(Fig.29) for the purpose of mass production of the species that is now fast becoming of
interest as an alternative live-feed for fishes in the hatcheries. Rice-bran was used as
feed and was given daily. The culture trial tanks were placed at different localities,
viz., in a partly shaded area and in an open area. It was observed that in the tanks
placed in a partly shaded area, the production was 1.1 kg/ton/month while that placed in
an open area failed to develop. The failure in the second tank may be attributed to the
drastic changes in the environmental factors. The pH value which was determined in an
earlier findings to be the most critical parameter in culture trial seemed to fluctuate
drastically in tanks which were placed in an open area. This large variation in pH value
was attributed to the degree of rainfall. The research in still ongoing.
Screening Of Local Zooplankton Species
Screening of Cladocerans was conducted from time to time
using zooplankton sampled from the FFRC ponds. Early indications were that Ceriodaphnia
cornuta (Fig. 30) and Diaphanosoma excisum (Fig. 31) could both be
successfully cultured in the laboratory. Large-scale culture of these species of
Cladocerans could not be done yet owing to the shortage of a good supply of phytoplankton.
Ceriodaphnia cornuta is much smaller in size when compared to Diaphanosoma
excisum. It was also slow moving which would render it more susceptible to predation
by the fish larvae. Various species of Alona were also noted in the cultures from
time to time. However, these were not considered suitable species for fish fry except
perhaps for the Marble Goby because they were basically scrapers of algae and tend to move
about close to the substrate. Ostracods have also been observed in old cultures. Some of
these are able to remove tough algal patches on the glass surfaces of culture bottles.
Genetic Enhancement of Major
Culture Species
Genetic Enhancement of Red
Tilapia
For the Red Tilapia, selection was for colour, fast growth
rate, and body conformation. For the selection of colour, three factors were of interest,
mainly, percentage of progenies possessing overall red body colour, reduction of
melanophores so that individuals were pure red, and intensity of the red colour. For this
year, the percentage of red-coloured progenies was less than the 99% obtained for 1995 for
fry production in ponds. However, for fry produced in fibreglass tanks, the 100% achieved
in previous years were maintained. For the third objective under colour selection, not
much was done because market demands changed from intensely red tilapia to whitish red
fish. The Red Tilapia strain in the FFRC continued to register a growth rate of 3
grams/day. With better management and proper feeding, better rates could be obtained. On
the whole, the growth rate achieved was good enough for commercial farmers to culture
tilapias profitably.
The main point of interest was actually the selection for
body conformation. The ultimate aim of this was to produce tilapias that have higher flesh
weight per millimetre of standard length. Two main approaches were experimented on.
Firstly, there was selection for breeders having superior body conformation, that is,
smaller head, deeper body, and higher flesh weight. This was done by means of comparison
with a selection index based on data points from more than 2,000 individuals. The
collection of more data points for bigger individuals allowed for the upgrading of the
selection index generated previously. The second approach to obtain good body conformation
was to cross the red tilapia with the blue tilapia (Oreochromis aureus). This was
done because the blue tilapia is well known for its smaller head and deeper body. Results
indicated that the resulting fry grew very well but quite a high percentage actually
possessed grey body coloration. The F1 showed a 47.15% improvement in terms of
overall body conformation, this, taking into account head length, body depth and body
weight. When the fish grew to an average weight of 222 grams, an advantage of 33% was
obtained. Various stocks of tilapias are presently maintained in the FFRC.
For the Red Tilapia, there are three varieties/strains,
namely, the Thai Red Hybrid, the Chitralada Red from the AIT (Asian Institute of
Technology, Thailand) and the Israeli Red. Four species of tilapias are available: Oreochromis
mossambicus, Oreochromis niloticus, Oreochromis aureus and Tilapia zillii.
The Genetics Section of the FFRC is also contemplating plans to include other potentially
important cichlids for research. The much-awaited International Game-Fish Association
Class One game fish, the Peacock Bass, Cichla monoculus (Fig. 32) was finally
obtained through the courtesy of Sianlon Aquaculture Sdn. Bhd., Batu Pahat, Johor. Six
individuals were stocked into J-38, a 1/100th acre pond, which already has an
established population of Gambusia affinis and Oreochromis mossambicus. The
initial weights of the Peacock Bass were between 5.6 to 12.6 grams. The fish have now
recorded more than 100 grams each.
Genetic Selection of Guppies, Poecilia
reticulata
Genetic selection of guppies was done with the objective of
coming up with some fanciful strains, as this is where commercial farms could make profits
in the Guppy trade. Stocks of guppies were obtained from the Nutrition Section of the FFRC
and also from various ornamental fish shops in Malacca. In general, most guppies on sale
seem to be of inferior quality and few actually meet the standards of being the championed
guppies. A few males of the Deep Blue Strain were carefully selected from ornamental fish
shops and bred with females in the FFRC.
Strains that have emerged with some consistency were the
Tuxedo Red, Tuxedo Neon Blue, Tuxedo Deep Blue, Rainbow, and Yellow Snakeskin. Wild type
males were culled and fed to predatory fishes such as the Marble Goby (Oxyeleotris
marmoratus) and the Snakehead (Ophicephalus/Channa striatus). Various
interesting potential characteristics such as red spots in a blue tail have been observed
and efforts are being made to monitor such characteristics to determine how well they are
propagated. A few fibreglass tanks were used to keep discarded or superfluous individuals
so as not to lose genes and thereby causing an increase in inbreeding.
Selection for disease resistance was carried out.
Individuals produced are yet to be tested.
Genetic Selection of Marbled Goby, Oxyeleotris
marmoratus
This was mainly an effort to determine whether selection
for growth rate could be feasible. Research done indicated that individuals of about 80 to
90 grams could actually be spawned. However, the main obstacle to the farming of the
Marble Goby is the supply of seed because over the last 30 years, there was actually very
little progress in finding a suitable feed for their hatchlings. With a mouth diameter of
merely 60 microns, hatchlings are unable to take well-established live-feeds. It was for
this purpose that the zooplankton genetics research was initiated with the hope that some
suitably sized species of rotifers or other organisms may be found.
A preliminary laboratory study on the growth rate of
juveniles was conducted. It was found that juveniles of 30-46 mm total length and
0.21-0.85 grams weight grew to a total length of 34-49 mm and weighed 0.38-1.06 grams in
duration of 83 days. Growth rate has accelerated now that the fish are able to predate on
guppies and chunks of thrash fish.
FISH HEALTH
A rapid and simplified immunoassay for detection of A.
hydrophila from fish, water and aquatic environment
More than 120 bacterial samples were collected from various
sources including wild and cultured fish, water samples from river and rearing ponds,
well, drain, tap water, prepared food samples sold at stalls and also chicken and
vegetables sold in the market. From the 120 samples, 80 strains of A. hydrophila
were isolated and positively identified.
The 80 strains isolated were subjected to further
confirmatory biochemical and serological tests to select the `true' A.
hydrophila strains. Virulence testing for the presence of enzyme's activity of
chitinase and protease were also tested in vitro technique. From the tests 20 strains were
selected and further virulence testing on catfish only 5 strains were finally accepted for
further works. Intramuscular injection of bacterial suspension of each strain were
performed (Fig. 33).
Active immunization and oral administration of egg
yolk antibody against A. hydrophila on catfish (Clarias macrocephalus)
The immunization study showed that the antibody towards A.
hydrophila could be found in the chicken's egg yolk. This antibody gives
protection to fish when challenged with A. hydrophila introduced through
intraperitoneal injection, Fig. 34. In a separate experiment the egg yolk also have been
shown to help in the growth performance of the catfish.
Disease diagnosis and pathogenicity detection of the
bacterial species
Laboratory diagnoses were conducted on 20 reported cases of
diseased fish. The infections on the gills and skin of Koi and Tetra spp. were
caused by Protozoa, Ichthyopthirius multifiliis, Trichodina spp. and
Epistylis spp.. Monogenetic infection of catfish were caused by Dactylogyrus spp.
and Gyrodactylus spp. Aeromonas spp. were identified on most of the
cultured freshwater fish, ornamental fish and their waters and of which 60% were A.
hydrophila and the rest were A. sobriae and Aeromonas. spp.
 
  
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