JUNE 14–25, 1980
UNDP/FAO PROJECT THA/75/008
PAUL A. SANDIFER
MARINE RESOURCES RESEARCH INSTITUTE
CHARLESTON, SOUTH CAROLINA 29412
U.S.A.
I. Terms of Reference
To participate in meeting “Giant Prawn 1980” to be held in Bangkok, Thailand, between 15–21 June 1980.
To chair one of the sessions of the meeting.
To present an overview of cumulative experience with Macrobrachium.
To participate in discussions at sessions of the meeting.
To provide other consultancy services as are appropriate to project THA/75/008 and as requested by the Project Manager and his counterpart.
II. Itinerary and Activities
Sat. 14 June - Departed home (Charleston, SC), 6:15 AM.
Sun. 15 June - Arrived Erawan Hotel, Bangkok, 11:00 PM.
Mon. 16 June - Chaired Research Session 1 at Giant Prawn - 1980, participated in discussion, and presented two papers, one dealing with semi-intensive culture of prawns and another concerning rearing of prawns in brackish water.
Tues. 17 June - Continued participation in Conference; served as panel member and rapporteur for Research Discussion Session.
Wed. 18 June - Continued participation in Conference; discussed prawn farming with a variety of participants.
Thurs. 19 June - Continued participation in Conference.
Fri. 20 June - Participated in Conference Tour B. of Macrobrachium research facilities, hatcheries and farms and one Artemia farm.
Sat. 21 June - Continued on Tour B.
Sun. 22 June - Visited “front-yard” hatchery operated by Dr. Piamsak Menasveta at his home; then visited his prawn farm in the countryside outside Bangkok; discussed his work and facilities with him.
Mon. 23 June - Spent the day with Mr. Somsuk Singholka at the Chacheongsao Fisheries Station. Discussed a variety of problems with the Station staff, most dealing with the quality of the water available to the Station for use in hatchery work (see Section IIIfor recommendations and suggestions). Also, visited a most impressive private, back-yard hatchery and discussed its operation.
Tues. 24 June - Spent part of the day with Michael New discussing the Conference and my other activities and visited UNDP offices to complete administrative matters concerning my trip. Remainder of day was spent in preparing to leave Bangkok.
Wed. 25 June - Departed hotel 7:15 AM to return to Charleston.
Thurs. 26 June - Arrived home 3:00 AM.
III. Recommendations Concerning Chacheongsao Fisheries Station
The station staff apprear to rely very heavily on chemical treatment of both fresh and salt water before use for hatchery purposes. While there is nothing really wrong with their procedures, it is quite possible that some residual chlorine or formalin remains in the water when it is used and such residual could be in part responsible for the decreased production of postlarvae. As far as the basic water supplies are concerned, I suggest that the Station staff do more monitoring of water quality indicators, particularly total organics and ammonia. High organic loads can lead to rapid build-up of bacteria in the larval tanks, with resultant detrimental effects on the larvae, and ammonia can be directly toxin to larvae at relatively low levels. I further recommend that the Station staff consider installing biological filters to help improve the quality of the water before it is used. Details of filter design and operation are included in some of the references listed under #4. If such a filter is installed, care should be taken to operate it continuously and with as constant a load as possible to maintain efficiency.
The experimental recirculating system used for hatchery production was examined and discussed with Mr. Somsuk. My primary recommendations concerned replacing the sand with gravel and insuring some aeration through the filter so that pockets of toxic H2S do not develop. Refer to Spotte (1979) for details of filter construction (see recommended literature list, #4).
Station personnel seem to have developed an excellent working relationship with private prawn farmers, both large and small. I was most impressed with this aspect of their operation. However, I believe some important improvements could be made in the extension area, primarily in the kinds and amounts of data obtained from private farmers by the extension agents. Particularly needed are good statistics on production, both from hatchery and grow-out operations, and the relationships between gross production, survival, population characteristics, etc. and water quality, management procedures, and other site-specific farm factors. Also needed are economic data, including labor involvement, feed costs, and so forth. Finally, there does not appear to be any special attention being given yet to marketing and processing1. However, it seems likely to me that, with the combination of an excellent government extenstion operation and a progressive private farming sector the Thais may well produce more prawns than are needed for their local markets within a few years. Some planning needs to begin now for this eventuality.
IV. Recommended Literature
Spotte, S., 1979. Fish and Invertebrate Culture: Water Management in Closed Systems. 2nd Edition, John Wiley & Sons, New York, 179 pp.
Spotte, S., 1979. Seawater Aquariums. John Wiley & Sons, New York, 413 pp. Armstrong, D. A., D. Chippendale, A.W. Knight and J.E. Colt, 1978. Interaction of ionized and unionized ammonia on short-term survival and growth of prawn larvae, Macrobrachium rosenbergii. Biol. Bull. 154: 14–31.
Amstrong, D. A., M. J. Stephenson and A. W. Knight, 1976. Acute toxicity of nitrite to larvae of the giant Malaysian prawn, Macrobrachium rosenbergii. Aquaculture 9: 39–46.
Glude, J. B., 1978. The freshwater prawn Macrobrachium rosenbergii (de Man). TVA/EPRI, Jan. 1978. 59 pp. (manuscr.).
Nelson, S. G., H. W. Li, and A. W. Knight, 1977. Calorie, carbon and nitrogen metabolism of juvenile Macrobrachium rosenbergii (de Man) (Crustacea, Palaemonidae) with regard to trophic position. Comp. Biochem Physiol. 57A: 67–72.
Wicken, J. F., 1976. Prawn biology and culture. Oceanogr. Mar. Biol.
Ann. Rev. 14: 435–507.
Hanson, J. A. and H. L. Goodwin, 1977. Shrimp and Prawn Farming in the Western Hemisphere. Downden, Hutchinson and Ross, Inc., Stroudsburg, Pa. 439 pp.
