National Inland Fisheries Institute
Department of Fisheries
Bangkok, Thailand
I. INTRODUCTION
During the period under review (1988), the Department of Fisheries, through the National Inland Fisheries Institute, continued to support NACA activities by organizing NACA meetings, training courses, study tour programmes and undertaking research work on subjects that will benefit the fishery development in the region as a whole.
II. PROGRESS OF ACTIVITIES AND ACHIEVEMENTS
A. Contributions by the Government of Thailand
The Government of Thailand has remitted to UNDP the amount of US$10,000 from its national budget as its contribution to NACA. It has also provided its facilities in some of its freshwater fisheries stations for research work.
B. Staff Activities
During the year, the Regional Lead Centre in Thailand continued to participate in the research, information and training activities of NACA and provided technical advice to the project member countries. It also participated in the Seafarming Project. Staff activities can be summarized as follows:
Dr. Kamonporn Tonguthai, chief of the fish pathology research team, travelled to various member countries with a view to providing technical advice and initiating the regional research programme on the relationship between the environment and the fish ulcerative disease.
Philippines - 25 January-5 February
SR Vietnam - 29 February-4 March
China - 7–11 March
Burma - 13–16 March
Dr. Kamonporn Tonguthai visited Bangladesh on 10–14 April 1988 to make appropriate recommendations for the control of the fish ulcerative disease outbreak. She also consulted with UPM and IDRC officials in Malaysia on 30 November to 4 December in connection with the regional programme on the fish ulcerative disease.
Miss Sopa Areerat travelled to Bangladesh on 18–25 February to provide technical advice and initiate the regional research programme on the relationship between the environment and the fish ulcerative disease.
Dr. Sidthi Boonyaratpalin travelled to Sri Lanka on 14–19 February to investigate the fish disease outbreak.
Ms. Rajit Lala, fishery biologist from the Brackishwater Fisheries Division, was selected to participate in the 7th training course for senior aquaculturists in Asia. The training is being held in the Regional Lead Centre in the Philippines (RLCP) from 17 March 1988 until 17 March 1989.
Mr. Tavorn Jirasophonraksa, fishery biologist from the Freshwater Fishery Division, was selected to participate in the training course on integrated fish farming held on 18 April-17 August 1988 at the Regional lead Centre in China (RLCC).
Ms. Chotima Vanagosom, fishery biologist from the Brackishwater Fishery Division, was awarded a NACA fellowship to the training course on the fish disease diagnostics being held at the Universiti Pertanian Malaysia (UPM) on 4 July 1988 until 4 April 1989.
Mr. Suparp Pripanabong, technical officer of the Suratthani Brackishwater Fisheries Station, and one oyster farmer from Surrathani Province attended the training course on oyster culture conducted by the Seafarming Project in the Republic of Korea on 11 June-7 July 1988.
The Seafarming Project sponsored the participation of Mr. Leuchai Daroonchoo and Mr. Suchart Tachanavong, fishery biologists from the Brackishwater Fisheries Division, in the demonstration/training course on Eucheuma seaweed farming held in the Philippines on 2–21 May 1988.
Mr. Wichien Yongprapat, fishery biologist from the Brackishwater Fisheries Division, and two fishfarmers attended the finfish netcage culture training course held in Singapore on 4–21 September 1988.
Dr. Kitjar Jaiyen, director of the National Inland Fisheries Institute and RLCT director participated in the International Symposium on Aquaculture Research Needs for the Year 2000. This symposium was organized by the U.S. Department of Agriculture and the Indian Council of Agriculture Research in New Delhi, India, on 15–18 November 1988.
C. Study Tours and Training Activities
Upon the request of NACA, RLCT organized short-term training programmes and study tour programmes during the year under review.
Study Tours
Study tour on shrimp hatchery operations and culture technology for two participants from the Philippines (Philippine National Aquaculture Centre) on 10–24 April 1988.
Study tour on freshwater shrimp culture for one participant from India on 16 May-3 June 1988.
Study tour on backyard hatchery for fishery officers from FAO Rome and 20 participants from Israel on 9 May 1988.
Study tour on Thai fish disease research programme for two participants from India on 5–11 June 1988.
Study tour for an official from the Shanghai University of Fisheries, China, to visit some private fish farms near Bangkok on 16 September 1988.
Study tour programme for five participants from Vietnam on 5 October to 4 November 1988, to visit fisheries institutes, centres and organizations with a view to exchange information on scientific aspects, planning and strategy adopted for aquaculture development.
Study tour on frog farming for two scientists from the Primary Production Department, Singapore, on 31 October to 11 November 1988.
Observation-cum-training tour for five fishfarmers from Sri Lanka on 10–14 October 1988.
Training Programmes
RLCT organized a training course for 21 participants from six member countries of the Regional Seafarming Project at the Satul Brackishwater Fisheries Station on 1–21 August 1988.
Six sessions of the on-the-job-training on backyard hatchery operations and management for participants from six countries were implemented. The first two sessions (two participants per session) were conducted in Chachoengsao Province for three weeks each session. The other sessions were held at Samut Sakorn Province (at two per session, except for the last session which had 4 participants). All 14 participants have returned home equipped with expertise on the Thai backyard shrimp hatchery technologies that they may adapt for use in their respective countries.
Part of the one-year Regional Training Programme for senior aquaculturists in Asia (1988/1989 session) was conducted in the Regional Lead Centre in Thailand on 27 July to 15 August 1988. The 18 participants were given training on induced spawning of catfish (Clarias and Pangasius) and Thai barb (Puntius); cage culture of Pangasius; and pond culture activities of snakehead and Macrobrachium rosenbergii, etc.
D. Research Activities
RLCT has undertaken the following research work with financial support from the Royal Thai Government and certain inputs in terms of chemicals and necessary equipment from NACA:
1. Mass selection of Macrobrachium rosenbergii (de Man)
Mass selection on giant freshwater prawn was conducted in Ayuthaya Inland Fisheries Centre between 1986 to 1988. Thirty thousand prawn juveniles were grown in a 0.32-ha earthen pond. After 8 months, mature males and females were collected and kept separately for one month. The prawns were chosen at random for control line and the biggest-sized were chosen for the selected line to produce the offspring. The selected and control line postlarvae were grown separately in four 0.16-ha earthen ponds (2 ponds per line) for eight months. After one generation of selection at the age of 10 months, the selected prawns grew significantly, 17 per cent faster than the unselected prawns. The response to selection and realized heritability will be estimated after two generations.
2. Preliminary study on mass selection of Clarias macrocephalus
Mass selection technique was used for the preliminary studies on the growth in walking catfish (Clarias macrocephalus) and to determine selection response and realized heritability. Thirty-five pairs of the fish were bred by induced spawning with hormone injection. After nursing all the fry for 11 days, 12 thousand fry were stocked in two 200-sqm earthen ponds. After rearing of the fish for nine months, mass selection was used. Ten per cent of the fish of medium size were taken at random for the control (unselected line) and ten per cent of the largest fish were selected from each pond for the selected line. The selected line was 7.36 per cent heavier and 3 per cent longer than the control line after two generations of mass selection. The response to selection was 9.14 g, and 0.71 cm by weight and length. The realized heritability estimated was 0.24 and 0.28 by weight and length, respectively. Weight-specific mass selection should be used in the next generation to decrease variance of the fish population.
3. Realized response of Thai red tilapia to weight-specific selection for growth (3rd-5th generations)
Weight-specific selection techniques were used to study the growth in Thai red tilapia and to determine the selection response and realized heritability. In weight-specific selection, fish were selected once in six weeks to have approximately the same standard weight. Then they were selected for a second time based on their relative growth rate, between the 6th and 14th weeks. Weight and length of the selected line were greater than that of the control in every generation. The selected line was 18.7 per cent heavier and 8.57 per cent longer than the control line after the second generation of the repeat-experiment (overall 5 generations). The selection response was calculated and the difference between the mean final population and the control was 4.32 gm and 0.86 cm by weight and length respectively. The realized heritability estimated was 0.17 and 0.29 by weight and length, respectively. The selection procedure was shown to be effective for Thai red tilapia which can be considered as a promising candidate for genetic stock improvement.
4. Comparison of seed production of Nile tilapia and red tilapia in 50-ton cement tanks
The breeding of Nile tilapia and red tilapia was compared in ten of the 50-ton cement tanks (5×10×1 m) between 15 September and 14 December 1987. The sex ratio of brooders was 20 males and 40 females. Pond preparation, change of brooders and harvesting of fry were done once a month. Data from five ponds of each strain were averaged. The average of fry production per month was 10,017.32 per pond for Nile tilapia and 4,784.16 per pond for red tilapia. The production of fry per female was 251.78 and 119.6 for Nile tilapia and red tilapia, respectively. Revenue from fry sales was 1,007.13 baht/pond/month for Nile tilapia and 956.83 baht/pond/month for red tilapia.
5. Experiment on breeding and rearing of short-necked clam (Paphia undulata)
Short-necked clam (Paphia undulata) was successfully induced to spawn and the larvae produced were reared in the hatchery up to planting size which had an average shell length of 1.0-1.3 cm. Three methods of induced spawning were used, including temperature cycling, drying/immersion and Seratonin injection. The D-shaped larvae were developed about 12 hours after fertilization, and they measured 80 by 70 micron. It took about five days for the umbone and eight days for the pediveliger to be developed, The larvae lost their larval organs and formed the structures of the adult clam after metamorphosis. The food for larvae was Isochrysis galbana, Thallasiosira pseudonana and Chatoceros calcitrans. The temperature and the salinity of seawater used in this study were 28–30°C and 32–34 ppt, respectively. The average survival rate of larvae from D-shaped stage of metamorphosis was 75 per cent. Fairly high mortality was observed during the metamorphosis. Survival rate of larvae (from D-shaped stage) up to 30 days old averaged 28.4 per cent.
6. Essential fatty acid requirement of juvenile seabass
A study on the n-3 HUFA (n-3 highly unsaturated fatty acid) requirement of juvenile seabass, Lates calcarifer, in brackishwater was carried out. The preparation of squid liver oil concentrate containing four levels of n-3 HUFA 0.42, 0.69, 1.80 and 2.65 per cent in dry weight of the diet was used. Four groups of fish were maintained on these diets for 12 weeks. Some of the fish fed on the diet 0.42 per cent n-3 HUFA began to show reddening of the fins from the second week and later they manifested chronic EFA (essential fatty acid) deficiency symptoms. Their growth rate and feed efficiency were significantly lower (P 0.05) compared with other treatments. The fish fed on the diet containing 0.69 per cent n-3 HUFA also showed slight EFA deficiency symptoms. During the 12th week of this experiment, the diet containing 1.80 per cent n-3 HUFA provided the best growth rate. The mortality was low and not significantly (P 0.05) correlated to various levels of n-3 HUFA in the diets. It is concluded that n-3 HUFA has an essential role in seabass nutrition and the quantitative requirement is approximately 1.80 per cent in dry weight of the diet for good growth, high feed efficiency and freedom from EFA deficiency symptoms.
7. Study on vitamin requirement of seabass, Lates calcarifer Bloch, in sea water
Seabass fry (Lates calcarifer Bloch) were fed with test diets, No. 1, the control, a vitamin-complete diet; Diets No. 2 to No. 6, from which B1 (thiamine), B2 (riboflavin), B6 (pyridoxine), pantothenic acid and vitamin C (ascorbic acid) were deleted, respectively. The average weight gains were determined at the end, which were 18.14, 17.47 and 18.47 gm in fish fed with diet deficient in vitamin B6, panthotenic acid and the control, respectively. Those average weight gains were not different during 90 days of the experimental period, Vitamin B6 deficiency resulted in loss of equilibrium, eroded fin, anorexia and some of them were floating. The survival rate was 56 per cent. The pantothenic acid-deficient diet resulted in loss of equilibrium and erosion of fins. Some of the fish floated and the gills were covered with excessive mucus. But fry still enjoyed feeding and the survival rate was about 72.67 per cent.
The average weight gain of fish deficient in vitamin B1, B2 and vitamin C were 12.38, 11.43 and 2.51 gm (75 days), respectively, which were different from the control at the end. Fish deficient in vitamin B1 had dark skin at 30 days, lost equilibrium, fins were eroded and showed anorexia after 60 days and survival rate was 56 per cent. The fish fed with vitamin B2 deficient diet for 15 days showed opaque eyes and exophthalmia. Thirty days later, the fish lost equilibrium, fins were eroded and showed anorexia and some short bodies at the end. The survival rate was 45.33 per cent.
8. Relationship between giant freshwater prawn diseases and water quality in nursery ponds
Sixty-four water samples from diseased nursery ponds and 63 water samples from the normal nursery ponds were analyzed. The average of pH and unionized ammonia of water from diseased ponds were significantly higher than that of the normal nursery ponds. The average pH from diseased nursery ponds was 7.6 and unionized ammonia was 0.0785 mg/l while the average pH from normal ponds was 7.4 and unionized ammonia was 0.0301 mg/l.
9. Effect of some chemoterapeutics on Vibrio harveyi
V. harveyi from Peneaus monodon were treated with eight chemotherapeutics, namely, Furanace, Nitrofurantoin, Oxytetracycline, Choramphinical, Dimeton Soda, Trimethoprim-Salfamethoxazole, Choromycin and Acriflavin at the Concentration 0, 1, 3, 5 and 10 ppm. Results showed that the effective chemotherapeutics were Furanace and Nitrofurantoin, and the minimum concentrations were 1 and 3 ppm, respectively.
10. Disease of tiger prawn (P. monodon)
Identification of the disease of P. monodon larvae. The larval stages (nauplius, protozoa, mysis and post-larvae) of tiger prawns from a private hatchery were examined for bacterial, parasitic and fungal organisms. The luminescent bacteria, Vibrio harveyi, was isolated from the luminous tiger prawn larvae only at protozoa and mysis stages. Zoothannium protozoa was also found on the exo-skeleton and gills of protozoa and mysis larval stages of tiger prawn. No fungal disease was found in any stage.
Determination of the efficacy of chemicals and drugs. The tiger prawn larvae (nauplius stage) were obtained from the private hatchery at Chantaburi Province and brought to the laboratory where they were stocked in six 300-L fibre glass tanks at the rate of 100,00 nauplius/1000 L. Various concentrations of antibiotic drugs, e.g. oxytetracycline, chloramphenical were used to treat the infected tiger prawn larvae with three replications. The survival rate of the larvae between the different antibiotic treatments and the no-treatment control was compared. Parasitic, bacterial and fungal diseases were examined throughout the experimental period. The experiment is in progress.
E. Secondment of Junior Scientists for One-Year In-Service Training
In order to fulfill NACA's objective in the implementation of the programme for secondment of junior scientists from the region to receive in-service training in research methods and approaches required for aquaculture technology improvement and development, the Regional Lead Centre in Thailand has selected two scientists for training in the field of fish nutrition and one scientist in the field of fish disease. The fish nutrition training for one Indonesian and one Chinese scientist started in April 1988 and the fish disease training for an Indonesian scientist in October 1988.
