AQD Books and Book Chaptershttp://hdl.handle.net/20.500.12066/6532024-03-28T20:32:11Z2024-03-28T20:32:11ZComparative analysis of small-scale aquaculture industry in three Southeast Asian countriesMatsuura, Tsutomuhttp://hdl.handle.net/20.500.12066/73712023-08-29T03:52:41Z2007-01-01T00:00:00ZComparative analysis of small-scale aquaculture industry in three Southeast Asian countries
Matsuura, Tsutomu
Nakamura, Koji
In many Southeast Asian countries, coastal fishing villages are increasingly encouraging their inhabitants to start small-scale aquaculture as a way of reducing the labor involved in fishing and diversifying their sources of income. This study aims to conduct a comparative analysis of small-scale aquaculture in the Philippines, Thailand and Malaysia (hereinafter referred to as the ‘three countries’). Aquaculture plays a leading role as a secondary source of income in the Philippines, and is both a primary and secondary source of income in Thailand and Malaysia. Even if a highly productive method of aquaculture were introduced in the Philippines, however, it would not see much uptake because it would be prone to damage by typhoons. Thailand and Malaysia, however, which are unaffected by typhoons, have rapidly increased their mussel production thanks to the active introduction of highly productive aquaculture methods. Our search of the points that developing areas in the three countries have in common revealed that many people started small-scale aquaculture after the mid-1990s in advanced areas, and that most small-scale aquaculture operators say that shellfish are easy to culture and want to continue in the business.
2007-01-01T00:00:00ZComparative analysis of pattern of fishcage culture using marine/brackish water in three Southeast Asian countriesMatsuura, Tsutomuhttp://hdl.handle.net/20.500.12066/73732023-08-29T03:53:51Z2007-01-01T00:00:00ZComparative analysis of pattern of fishcage culture using marine/brackish water in three Southeast Asian countries
Matsuura, Tsutomu
Nakamura, Koji
Production by fishcage culture using marine/brackish water has increased drastically since the mid-1980s, when the technology for developing sea bass hatchery fry was established. In the 1990s, it grew further, due to the start of production of grouper and snapper hatchery fry. We conducted a comparative analysis of production by fishcage culture and patterns of fishcage culture in the Philippines, Thailand, and Malaysia, all of which are major producer of fish by fishcage culture using marine/brackish water in the Southeast Asian countries. We compared of fishcage culture management between the reference and current year and analyzes the average of the reference year (the year when fishcage culture started; the same hereinafter) and current year (2004). In terms of production of cultured fish by kind, sea bass showed a more than 50% decrease - from 67% to 32%, whereas grouper saw a nearly doubled ratio from 20% to 39%. Snapper remained almost the same, at 29% to 28%. Other fish (mainly rabbitfish, threadfin bream and grunter) saw an increased ratio from 5% to 16%. We compared the management of fishcage culture between the reference year and 2004. We looked into the ratio of production by type of fish and found that sea bass showed a decreased ratio to less than half from 67% to 32%; while grouper showed a near doubling of its ratio from 20% to 39%. Snapper remained almost unchanged, at 28% to 29%; and other kinds of fish increased their ratios from 5% to 16%. In terms of operating cost per kilogram for farming groupers, fishcage culture costs more than fishpond culture. Fishcage culture, however, is more convenient and productive than fishpond culture, and requires lower initial cost than fishpond culture, since the former does not require an initial outlay for constructing a pond or management of water quality. Accordingly, fishcage culture shows overwhelmingly higher production than fishpond culture.
2007-01-01T00:00:00ZDetection of betanodaviruses from different organs of broodstocks and wild juveniles of orange-spotted grouper, Epinephelus coioidesKiryu, Ikunaride la Peña, Leobert D.Maeno, Yukiohttp://hdl.handle.net/20.500.12066/73702023-08-29T03:52:21Z2006-01-01T00:00:00ZDetection of betanodaviruses from different organs of broodstocks and wild juveniles of orange-spotted grouper, Epinephelus coioides
Kiryu, Ikunari; de la Peña, Leobert D.; Maeno, Yukio
Nakamura, Koji
Aquaculture of grouper including orange-spotted grouper suffers losses from viral nervous necrosis (VNN). This disease usually occurs in larval stage resulting in a high rate of mortality. It is conceivable that vertical transmission from subclinically infected broodstock fish to the brood is the major route of infection. However, there are only a few studies regarding the fish subclinically infected with VNN and the evidence for a causal relationship between subclinically infected adult fish and vertical transmission remains tenuous. The purpose of this study is to reveal the distribution of the virus in asymptomatically infected fish. Six healthy broodstocks of orange-spotted groupers with body weights ranging from 5 to 12 kg were used and 14 different organs were collected. Cell culture and PCR methods were used to detect the virus. Additionally, 8 wild juveniles with body weights ranging from 2 to 4 g were also analyzed. In our results, the virus was detected by means of PCR but not by the cell culture method. All the broodstocks and wild juveniles were positive in the PCR test except for one juvenile. The highest detection rate of the virus among organs was the brain. However, the virus gene was also amplified from organs other than the central nervous system (CNS). We hypothesize that the virus was latently retained in the CNS of subclinically infected fish and when the fish immune system was weakened such latent virus was released from CNS to the peripheral organs including the gonad. This mechanism might provoke the vertical transmission infection.
2006-01-01T00:00:00ZArachidonic acid enrichment of rotifers and effects of dietary arachidonic acid on broodstock performance of rabbitfish Siganus guttatusChavez, Denny R.Ogata, Hiroshi Y.Garibay, Esteban S.Sollesta, Hananiah T.Tibubos, Keneth R.http://hdl.handle.net/20.500.12066/73742023-08-29T03:54:28Z2006-01-01T00:00:00ZArachidonic acid enrichment of rotifers and effects of dietary arachidonic acid on broodstock performance of rabbitfish Siganus guttatus
Chavez, Denny R.; Ogata, Hiroshi Y.; Garibay, Esteban S.; Sollesta, Hananiah T.; Tibubos, Keneth R.
Nakamura, Koji
Rotifers (Brachionus sp.) were cultured with various combinations of baker’s yeast, Nannochloropsis sp., Culture selco, and DHAPS with or without supplementation of arachidonic acid (triacylglycerol form). Rotifers were able to be enriched with emulsified- arachidonic acid supplemented to culture media. Considered the reciprocal ratios of arachidonic acid, EPA and DHA in rotifers, rotifers pre-cultured in Culture selco and then cultured in DHAPS had the best balance of essential fatty acids, and the optimum level of arachidonic acid supplementation to DHAPS appeared between 0% and 5%.
A feeding test was conducted to investigate the effects of arachidonic acid on the broodstock performance of rabbitfish (Siganus guttatus), one of the commercially valuable species in mangrove areas. A diet with 1.5% of arachidonic acid supplementation appeared to affect negatively the reproductive performance of S. guttatus broodstock, perhaps due to the excessive supplementation. Considered together with results of mangrove red snapper in 2003, the optimum supplementation of arachidonic acid in broodstock diets might be around 0.5%.
2006-01-01T00:00:00Z