Improved hatchery and growout technology for marine finfish in the Asia-Pacific region

Many of the research activities of FIS/2002/077 have been delayed by various changes within the participating agencies. This has necessitated a major revision of the project, and has effectively delayed its implementation by 6-12 months.

Hatchery technology
Preliminary sampling has been carried out to assess the nutritional requirements of grouper larvae, and to identify the causes of the deformities that are commonly seen in hatchery-reared fish in Indonesia.

Grow-out feeds
Evaluation of the use of poultry offal silage meal to replace fishmeal in grouper diets indicated that the inclusion of poultry offal silage meal at rates up to 20% (equivalent to a 37% replacement of fish meal protein) had no significant effect on fish growth, survival or carcass composition of juvenile E. fuscoguttatus. Higher levels of replacement may be beneficial but possible deficiencies of methionine, histidine and lysine may have to be overcome through the use of crystalline amino acids or complementary protein sources.

Digestibility studies to quantify the apparent dry matter, protein and lipid digestibility of six test feed ingredients, three of animal origin - poultry offal meal, golden snail and mysid meal - and three of plant origin - fine rice bran, maize meal and sorghum meal - have commenced at RICA Maros. For animal feed ingredients, the substitution rate is 40% while for plant feed ingredients, the substitution rate is 30%.

Asia-Pacific Marine Finfish Aquaculture Network
Extension and coordination activities, carried out through the Asia-Pacific Marine Finfish Aquaculture Network (APMFAN), have continued from the earlier grouper aquaculture project (FIS/97/73). Private sector support for APMFAN has been provided by Skretting, who provide support for the electronic publications (eNews and eMagazine) and are sponsoring four participants in the grouper hatchery training course over two years.

The results of FIS/97/73 were published as an ACIAR Monograph (no.110 - Advances in Grouper Aquaculture) and around 1,750 hard copies have been distributed and over 196 downloads of the electronic version recorded.

Two practical extension guides were produced:
A Guide to Small-Scale Marine Finfish Hatchery Technology
A Practical Guide to Feeds and Feed Management for Cultured Groupers
Around 150 hard copies of each have been distributed, and 1,364 and 870 downloads (respectively) of the electronic versions recorded. These two guides are currently in the process of translation into Indonesian, Thai and Vietnamese for distribution to farmers and investors in Asia.

Twenty-six issues of the APMFAN eNews were produced up to 30 June 2005, and three issues of the APMFAN eMagazine were produced. The distribution list for electronic publications is now around 1,088.

The 3rd Regional Grouper Hatchery Production Training Course was successfully carried out at the Brackishwater Aquaculture Development Centre, Situbondo, East Java, Indonesia from 18 April to 8 May 2005. There were a total of 17 participants from Australia, Brunei Darussalam, Indonesia, Malaysia, Maldives, Marshall Islands, Singapore, and Vietnam. Skretting sponsored a private sector participant from Vietnam as part of that company's support for APMFAN. APMFAN sponsored a fisheries officer from Aceh to participate in the training course as part of the capacity building for rebuilding the aquaculture sector in Aceh.

The first Study Program on Marine Aquaculture and Seafood Markets in Southern China (Guangzhou, Dayawan, Shenzhen, Shanwei, Yau Ping and Hong Kong) was successfully carried out from 4-15 July 2005 as an APMFAN activity. The Study Program was organized by the Network of Aquaculture Centres in Asia-Pacific (NACA), in cooperation with the Guangdong Provincial Bureau of Ocean and Fisheries, Guangdong Fishery Society, Guangdong Dayawan Fishery Development Center (Department of Marine and Aquatic Products, China), the Agriculture, Fisheries and Conservation Department (AFCD) - Hong Kong SAR. The Study Program introduced participants from exporting and producing regions in the Asia-Pacific area to the markets and marine aquaculture in southern China. There were a total of 14 participants from China, Hong Kong, India, Indonesia, Maldives, Marshall Islands, Philippines, and Singapore.

The process of formalising participation in APMFAN is continuing. The Terms of Reference for Regional Resource Experts (RREs) and Regional Resource Centres (RRCs) have been developed (based on those developed for the NACA Aquatic Health Management Program) and an official letter has been sent to member governments. Further follow up actions will be taken over the second half of 2005.

Hatchery technology
Collaborative activities between researchers at Gondol Research Institute for Mariculture, Bali, and the Philippines have commenced to transfer hatchery production technologies to improve hatchery production through improved larval nutrition. This work will particularly focus on coral trout, Plectropomus leopardus.

Mr Ketut Suwirya (GRIM Bali) visited Northern Fisheries Centre, Cairns, in February 2006 for training in larval enzyme analysis techniques. A follow-up visit was made by DPI&F staff to GRIM in April 2006 to continue the development of larval enzyme analyses using material supplied by GRIM and to initiative collaborative experiments:
Sampling protocols for reef fish larvae for digestive enzyme analysis were developed and tested successfully;
A time series of Plectropomus leopardus larvae and juveniles was sampled to provide baseline data on digestive enzyme ontogeny in this species;
Samples of different-sized P. leopardus larvae at the same age were sampled to provide better information on the impacts of size stratification amongst same-age cohorts of larvae.
A series of follow-on experiments was developed and agreed for implementation following the project visit.

Develop cost-effective grow-out diets
Digestibility of alternative feed ingredients
The apparent digestibility of eight local feed ingredients that could be used for pelleted grouper feeds was determined in two experiments with juvenile tiger grouper at Research Institute for Coastal Aquaculture (RICA), Maros, Southern Sulawesi. Each experiment entailed a reference diet and four test diets in which the test feed ingredient was substituted at 40% for poultry offal meal, mysid meal, golden snail meal or green mussel meal or 30% for rice bran, yellow corn, white corn or sorghum. Dry matter, protein, lipid and energy digestibility coefficients ranged from 59.4 to 69.9%, 83.4 to 88.9%, 62.0 to 93.9 and 70.8 to 82.8% respectively for the animal meals and from 36.3 to 52.5%, 41.3 to 52.1%, 23.7 to 65.8% and 39.1 to 45.1% for the plant meals, respectively. The digestibility of golden snail meal was consistently lower than other animal meals. This information will enable grow-out feeds for tiger grouper to be formulated on a least-cost digestible nutrient basis.

Substitution of fish meal
Golden snails are a prevalent and difficult to control pest of rice paddy fields that may have potential as a partial replacement of fish meal in grow-out feeds for grouper. Although the digestibility of golden snail meal was shown to be not as good as other animal protein sources, it is nonetheless a cheap and readily available alternative protein source. Research at RICA Maros demonstrated that replacement of fishmeal at inclusion rates of up to 20% did not adversely affect growth and survival of tiger grouper.

Five farmers and staff from Yayasan Palu Hijau (Central Sulawesi) attended a short course on grouper feed management at RICA Maros from 19 to 23 September 2005. Central Sulawesi has suffered substantial degradation of 'trash' fish stocks to support growing demand for feed for reef fish caught and held or grown out in cages for the live reef food fish trade. The training undertaken by Maros staff is intended to provide YPH staff with the technical skills to influence fishermen to use alternatives to 'trash' fish.

Asia-Pacific Marine Finfish Aquaculture Network
Five editions of the Marine Finfish Aquaculture e-Newsletter were produced (No's 27-31). There are currently 1,130 subscribers to the e-Newsletter. Four editions of the AMPFAN e-Magazine (No's 5-8) were included in 'Aquaculture Asia' magazine. Downloads of electronic versions of individual magazines range from 567 to 2,582 per issue; there are about 350 subscribers to the printed version.

The publications 'A Guide to Small-scale Marine Finfish Hatchery Technology' and 'A Practical Guide to Feeds and Feeding for Cultured Groupers' have been translated into Thai by Department of Fisheries staff. Both guides have been used by Thai DOF staff for training. A training course was organized by Krabi Coastal Fisheries Research and Development Centre (CFRDC), DOF from 30 June to 2 July 2005 on basic farm operation of better management practice. Twelve cage fish farmers attended this course. CFRDC supported training facilities, staff, dormitory and technology, and NACA supported training materials and meals.

On 24th-25th of November 2005, Mr. Hassanai Kongkeo and Mr Koji Yamamoto (NACA) visited the tsunami-affected fish farming communities of Koh Yao Noi (Phang-nga Province) and Koh Lanta Noi (Krabi Province), Andaman coast (where NACA has been working on fish farm rehabilitation) and disseminated the Thai versions of both guides.

The publication 'A Guide to Small-scale Marine Finfish Hatchery Technology' has also been translated into Vietnamese through the Support to Marine Aquaculture Development (SUMA) program. Around 1,000 copies have been disseminated to farmers throughout Vietnam.

Overall, project progress is adequate, although some problems with the spawning performance of broodstock at RIM Gondol (particularly with coral trout) has caused some delays in project activities. Where possible, project activities have switched to other species to avoid further delays.

Collaborative work at RIM Gondol has shown promise for using Vitamin C to reduce deformities in larval and juvenile grouper. The optimum enrichment method of L-ascorbyl-2-monophosphate in Artemia was found to occur at a dose rate 0.9 g/L for 6 h. The highest percentage of abnormalities was found in grouper larva fed with unenriched Artemia and commercial diet (control), indicating that vitamin C has an important role in controlling abnormality of humpback grouper larvae. However, it was noted that the deformities (nature and frequency) are highly variable, and that there may be some issues of consistency of results as a consequence.

Preliminary experiment done at RIM Gondol suggest that opercular deformities in juvenile grouper can be reversed using high doses of Vitamin C in the diet, but this finding requires more rigorous experimental follow-up.

Research into the digestive system of larval groupers has shown that they have weak enzyme activity during the endogenous nutrition stage of development (< day 3 post-hatch) and that significant changes in enzyme activity correlate with digestive tract development events prior to day 20 post-hatch. There are significant increases in the level of all enzymes after completion of stomach formation and onset of metamorphosis at day 28 (tiger grouper) onwards.

Of 4 rotifer strains isolated from North Sulawesi, Manembo-nembo strain was found to be the smallest, and thus more suitable for first feeding of grouper larvae. The smallest rotifers (<120m) appear when cultured at salinities of 20 and 30 ppt for Manembo-nembo strain. There was no linear relationship between salinity and rotifer size.

Effect of dietary protein and lipid level on growth performance of tiger grouper during late-stage grow-out was evaluated at RIM Gondol using test diets with five levels of protein (38, 42, 46, 50, 54%) and two lipid levels (9, 15%). The results indicate that a dietary protein level of 38% is sufficient to support good growth of larger (>250g) tiger grouper. Fish fed high lipid diets were fatter and more energy of the diet was retained as body fat.

An evaluation of the digestibility of feed ingredients at RICA Maros has shown that tiger grouper efficiently digest animal feed ingredients, indicating that these ingredients have potential to be used as dietary replacements for fish meal. Some caution is advised for golden snail meal since its overall digestibility was inexplicably poor, perhaps indicating that unknown factors may be affecting its nutritional value. However, plant meals were less digestible than animal meals.

On-farm validation of grow-out feeds is being undertaken in Labuange Bay, Southern Sulawesi, where there are 5 commercial farms growing tiger grouper. Three treatments are being assessed: 'trash' fish, moist pellet, and commercial pellet. This trial stared in April 2007 and is still underway.

The Asia-Pacific Marine Finfish Aquaculture Network (APMFAN) continues to expand. Formalisation of the network has begun with 3 Regional Resource Centres proposed for Indonesia as well as 4 for India. In addition, 25 Regional Resource Experts have been proposed.

The electronic dissemination of information continues to be popular with users. APMFAN eMagazine (4 issues/year) averaged 1,575 downloads; while the APMFAN eNews (monthly) averaged 600 downloads. Training news and reports downloads were >600 - 1,370. Around 30 - 40% of traffic on the NACA website discussion forums is related to marine finfish aquaculture.

The 4th Regional Grouper Hatchery Production Training Course was held at the Brackishwater Aquaculture Development Centre Situbondo, 20 November - 9 December 2006. Twenty participants from 13 countries successfully completed the course, including two participants from BADC Ujung Batee, Aceh (supported by FIS/2006/002).

APMFAN also organised a marine finfish hatchery training course on behalf of the Secretariat for the Pacific Community for a group of 6 from Pacific Islands in May 2007 at Krabi Coastal Fisheries Research and Development Centre (Krabi CFRDC) of DOF Thailand.

Corporate sponsorship (from Skretting Asia) continues to contribute to support of APMFAN. The current agreement is to 2007-08 and includes:
Scholarships for grouper hatchery training course
Support for web site, news and communications
Further R&D cooperation and national marine fish aquaculture extension workshops are planned with additional funding support from Skretting Asia.

Larval rearing research continues to focus on improving larval survival and improving the quality of fingerlings produced in hatcheries. While some improvements have been made, progress has been limited due to unreliable egg production at some of the partner institutions. Research into the enzymic capacity of larval groupers is continuing at NFC Cairns, to support the use of inert diets as part of the larval rearing regime. This work has demonstrated that coral trout have lower levels of enzyme activity over the first 12 days post-hatch than tiger grouper (Epinephelus fuscoguttatus), which may help explain why Plectropomus species are more difficult to rear than other groupers.

Research into developing cultures of small (S-strain) and super-small (SS-strain) rotifer (Brachionus rotundiformis) has shown that most techniques to select for smaller rotifers have little or no long-term effects on population size. The most promising technique for reducing rotifer population size is isolating and culturing specific strains. Future work will examine whether strain hybridisation can reduce overall rotifer population size.

Collection and cold storage of amictic rotifer eggs was also evaluated. However, cold storage of amictic eggs was found to be effectively limited to 24 hours.

Techniques to culture small copepods - the calanoid copepod Parvocalanus - have been developed at NFC Cairns. Cultures of Parvocalanus are routinely used in larval rearing in Cairns and have replaced the use of Acartia for larval rearing. Two staff from Research Institute for Aquaculture No.1, Cua Hoi and Cat Ba hatcheries, in Vietnam, were trained in live food culture, including copepod culture techniques, at NFC Cairns.

Research into development of grow-out diets has focussed on trialling commercial pellet feeds against research diets or 'trash' fish. Results from commercial diets remain mixed. Coral trout (Plectropomus leopardus) fed a commercial pellet feed and a custom-made (RIM-Gondol) feed showed similar survival (46-49%), weight gain (411 and 422%), daily growth rate (1.38 and 1.41 g/day) and FCR (1.55 and 1.45).

However, in another trial RIM Gondol undertook a comparison of pellet diet and 'trash' fish fed to coral trout and coral grouper (E. corallicola). 'Trash' fish outperformed the commercial pellet with both species. Coral trout fed 'trash' fish were substantially larger (554 g) after 180 days than those fed the pellet (diet 366 g). Survival rate was similar: 72 - 75%. Growth differences in E. corallicola were less marked with fish fed 'trash' fish reaching 316 g compared with pellet fed fish 278 g after 180 days. However, survival of fish fed 'trash' fish was higher (96%) than those fed pellets (82%).

Trials at RICA Maros showed that tiger grouper fed commercial feed (dry pellet), moist pellet, or 'trash' fish have relatively similar whole body content of lipid and protein. Meat quality of fish fed commercial pellet, fed moist pellet, or 'trash' fish was well accepted generally by taste panellists and grouper consumers in Hong Kong.

Three issues of the APMFAN eMagazine (Nos. 9-11) and seven editions of the APMFAN eNews (Nos. 32 - 38) were produced during 2007-08. The Marine Finfish section of the eNACA web site continues to be a popular source of information on marine finfish aquaculture and a valuable mechanism for distributing extension information.

NFC Cairns provided on-farm training to two farmers on culture techniques for grouper with particular reference to methods of cage culture and fish grading. Also, training was provided to a barramundi hatchery operator on the culture of tiger grouper. This training provided the first fingerlings of tiger grouper produced by a commercial operator in Australia.

RICA Maros held a short training course for farmers from Sengata Regency (Kalimantan Timur Province) on feed preparation and feed management, 30 July - 5 August 2007 (in Sengata and Maros).

The APMFAN Grouper Hatchery Production Training Course was held twice during 2007-08: 9-29 July 2007 and 5-25 May 2008, at the Brackishwater Aquaculture Development Centre, Situbondo, East Java, Indonesia. As always, these courses were well attended by trainees from throughout the Asia-Pacific region.