Commercial aquaculture in Tonga has developed rapidly since the late 1990s after having established a link with the international market of giant clams Tridacnidae, as a source for ornamental traders of the aquarium market trade. The Tongan Ministry of Fisheries Mariculture Centre located in Sopu on Tongatapu is the only producer of giant clams, under the responsibility of the Aquaculture Research and Development Section of the Fisheries Division in Tonga. Marine aquarium traders are target customers whose licences have been provided by the Tongan Fisheries Division to export ornamental products (i.e. live corals, aquarium fish, etc.) to the international markets. In 2007, 8 017 giant clams were sold to the aquarium traders for export with an estimated value of USD 12 000, which represents less than 5 percent of total export production from the fisheries sector (Fisheries Annual Report, 2008), that also includes live fish.
Apart from giant clam culture, since the mid-1950s, more than five other species, including, Mozambique tilapia (Oreochromis mossambicus), edible oyster and mussels (European flat oyster - Ostrea edulis, Sydney cupped oyster - Saccostrea commercialis, New Zealand rock oyster - S. glomerata, Pacific cupped oyster - Crassostrea gigas and Lugubrious cupped oyster - C. belcheri), mullets (Liza macrolepis and Valamugil seheli) and seaweed (Eucheuma spinosum & Kappaphysus) have been trialled as potential aquaculture products since the mid-1950s, but have failed to become feasible ventures to operate at commercial levels. Only the winged pearl oyster (Pteria penguin) has managed to develop successfully to a somewhat small commercial scale with sales mainly in street markets to visiting tourists.
Currently, there are around six applicants seeking licences to farm sea cucumbers, however to date these licences have not been issued. Issues have arisen with supply of juveniles as the proposed sea cucumber farms will be heavily reliant on imported hatchlings, from an international commercial hatchery, and includes wild selected sea cucumbers species to improve the fertilization rate.
Overall, despite great advances in the last decade, aquaculture in Tonga, is still largely in experimental stages for most of potential aquaculture commodities. Further development of this industry is currently an ongoing process receiving technical support from the Secretariat of Pacific Communities (SPC), the Australian Centre for International Agricultural Research (ACIAR), the Japanese International for Co-operation Agency (JICA) and the Food and Agriculture Organization (FAO).
Although aquaculture is not new in Tonga, it is new to most Tongans. The main aim of aquaculture in Tonga over the last 20 years was to restock depleted reefs and assist the marine aquarium trade by culturing and rearing of giant clams, Tridacnidae. The experiences and results of trials have currently encouraged the government and the Fisheries Department to move Tonga’s aquaculture capacity more towards commercialization activities.
The first aquaculture experiments conducted in Tonga were fish pond culture systems, which were initiated in the mid-1950s, but later trialled for fish culture as part of an integrated farming system project with a piggery. In the early 1970s broodstock of the Penguin wing oyster (Pteria penguin) were imported from Japan for initial culture trials by a private company. However, in 1989 FAO’s South Pacific Aquaculture Development Project (SPAFP), as part of the FAO, persisted with the trial culturing of pearl oysters, supported by the Tongan Fisheries Division. This provided great assistance in carrying out stock assessment, spat collection surveys, and grafting techniques; these methods are still currently exercised by the pearl farmer located at the Vava’u Island group. Edible oyster and mussels were also introduced for the potential of further aquaculture projects in 1973–1974, but culture trials ended with inconclusive results.
In 1978, the Fisheries Mariculture Centre (FMC) was established with the assistance of theJapanese Government assistance, but only for the culture of mollies (Poecilia vittata) in order to meet the demand for tuna bait in commercial fishing; this project was terminated in the same year. The seawater pump system installed as a result of this project was demolished by a tropical cyclone in 1982 and consequently renovated in 1989 through the assistance of an ACIAR project to meet the standards of a giant clam culture system. Further upgrades by JICA in the late 1990s improved this facility to a seawater flow through system, which now is the Fisheries Mariculture Centre located in Sopu. As a result, commercial top (Trochus niloticus) and green turban (Turbo marmoratus) were included as culture species together with the giant clams species, but both were aimed for resources enhancement rather than commercial production. Hard corals and live rock farming are the most recent introduction to the cultured species at the Mariculture Centre. The project commenced in 2009, but thus far, there has been limited success as the markets for coral is highly competitive, and in addition, the recent global economic crisis has seen drops in demand for aquarium organisms.
The current pearl farming aquaculture project has the highest priority in Tonga, with other culture projects (clam, etc.), currently at the aquaculture section of the Fisheries Division being given secondary and tertiary priorities. Most of the pearl farmers are males with only two farms being owned by females; however, crafting tasks of the pearl oyster shells harvested from the pearl oyster farmers are mostly carried out by female labour. In terms of experience and skill, most of the pearl farmers rely on the technical advice and information of Tonga Fisheries Mariculture Centre. In fact, the majority of the people engaged in pearl farming have never attended any formal training or attachments overseas except for national training conducted on fisheries, with technical assistance provided by FAO and SPC/ACIAR through the Tongan Government.
Giant clams, trochus and green turban
The culture techniques for giant clam species (Tridacna derasa, T.maxima, T.squamosa, T.gigas, T.crocea) were successfully established by the Fisheries Mariculture Centre in 1989 with the technical assistance of ACIAR and supported by the Japanese Government under JICA, after the ACIAR programme terminated in the early 1990s. JICA also assisted with aquaculture activities until early 2000s when trochus commercial top (Trochus niloticus) and green turban (Turbo marmoratus) were included as an additional cultured species, after being introduced from Japan and Vanuatu for stock enhancement purposes. In fact, giant clam is the only major aquaculture product produced in Tonga since the late 1990s after being established internationally in the ornamental market by the aquarium traders, issued with licences by the Tongan Fisheries Division.
Penguin wing oyster
Penguin wing oyster (Pteria penguin) were introduced from Japan in the early 1990s for pearl oyster trials but the first results were inconclusive. In 1989, SPADP of FAO, continued the farming trial with the end results indicating low spat production from hatchery runs. However, by early 2008, hatchery runs, under ACIARs mini project programme of the Regional Pacific which includes Tonga, yielded around 300 000 spats successfully being produced. The oysters were transferred to the FMC oyster longline at Sopu for further grow-out and later distributed to the pearl farmers located in Vava’u. Approximately 4 000 spat have been produced, grown out and distributed to the pearl farmers from the mariculture hatchery, with the assistance of ACIAR/SPC (2008–2010). The current target pearl production is the half pearl or ‘MABE’ pearl, which is currently focused on supplying the domestic market for tourism purposes.
Hard corals & live rocks
The launch of hard corals and live rocks farming in 2009 was part of the technical assistance provided by SPC/ACIAR to the Pacific Region, which aims to produce cultured live rocks and corals for supply to the aquarium ornamental trade. In August 2008, the Tongan Government put a national ban on the harvest and export of both live rocks and corals. This resulted in one company closing down, and as a consequence, other companies having to switch to target and catch other species (fish/invertebrates) in order to stay in business. As result, SPC provided technical assistance with ACIAR funding to trial aquaculture live rocks and corals at the mariculture facility in Sopu. Market trials are still in progress, but no export has been made since launching this project.
Tilapia farming initiated in the mid-1950s and followed up with other various culture trials such as introducing the species into freshwater and brackish lakes throughout the Tonga Island chain, but no major large-scale production ever eventuated, as local people lost interest in the species. Currently, locals treat tilapia as a pest, as a result of similar cases, whereby, tilapia were introduced into a brackish lake in which milkfish Chanos chanos were prominent, but soon disappeared after a few years, where tilapia is thought to be the most likely culprit by competing with the milkfish and eating their larvae. However, the introduction of tilapia to Tonga had a secondary aim in trying to reduce the mosquito population, but this attempt was also not successful. As a result, no more tilapia farming exists except for fishing at various freshwater bodies for home consumption only.
Mullet is a high priority aquaculture product, as it is the most commonly target fish species by gillnet fisherman. As a result, mullet fry of flathead grey mullet Mugil cephalus were imported from Hawaii in 1990 and introduced to Lake Ano, which is located in the Vava’u group. The sea mullet grew to adult stages but no natural spawning occured. In 1992-1993, mullet fry were collected from the coastal area of Tongatapu and stocked into pens culture for grow-out, but this project was terminated in 1995 due to the production costs of the mullet being too high when compared with sale prices at the local fish market (Fa’anunu et al., 1994).
In 1982, an experimental trial with seaweed farming for Eucheuma spinosum and Kappaphycus initiated after importation of seed stock from Fiji, by a private company, and were planted at a farm site in the Vava’u group. The Fisheries Division also set-up an experimental farm at Fanga’uta lagoon located in Tongatapu with the seeds transferred from Vava’u in 1986. By 1987, 14 farmers were operating, with each farmer possessing around 50 lines. After harvesting in 1987, no more farming activities continued due to market issues (Annual report, Fisheries Division, 1989).
The Fisheries Mariculture Centre at Sopu, Fisheries Division, was first established in 1978 and upgrade during late 1990s with the technical assistance of the Japanese Government (JICA). Currently, giant clams, trochus, greensnail, soft and hard corals, live rocks, and sea cucumbers are the aquaculture species in place at the facility, but the focus is on experimental activities with the exception of giant clam juveniles, which are sold to local traders for export.
The Fisheries Mariculture Centre at Sopu, Fisheries Division, is the major producer of aquaculture commodities (i.e. giant clams, trochus, greensnail, live rocks and hard & soft corals) within Tongatapu. The target market is focused on the aquarium and ornamental trades with part-time/seasonal focuses for reef stocking enhancement programmes. Table 2 below illustrates total production currently held at the FMC including the estimated production from the pearl farmers.
The graph below shows total aquaculture production in Tonga according to FAO statistics:
Aquarium market – International
The Sopu Fisheries Mariculture Centre is the main producer of giant clams production for exportation by the Aquarium operators, in fact, the demands from the international market cannot be met by the current production of giant clams.
‘MABE’ – Local market
For half pearls ‘MABE’, the primary markets for this product consists of the simple jewelry and souvenirs for tourists travelling to and through the Vava’u Island group, which is the major tourist destination in Tonga. No data has been recorded for the number of items sold at the local markets annually, but it is estimated that 500–800 pieces half pearls were sold during 2009 and less than 500 pieces sold in 2010.
The giant clam species is the major revenue contributor to the government from aquaculture activities. Giant clams are also a good source of animal protein in terms of wild stock enhancement carried out by the Tongan Fisheries Division together with the trochus and green turban.
There is little doubt that the contribution of ‘MABE’ production to the local economy of the people in Vava’u clearly provides small-scale employment for local people, as most of the pearl farmers are owned and operated by families (small-scale aquaculture), rather than large scale farms. The staff currently employed at the aquaculture section of the Fisheries Division provide the only form of employment opportunity in Tonga, unless the promotion and development of aquaculture activities to a commercialized level occurs.
Aquaculture activities in Tonga are administered by the Fisheries Division of the Ministry of Agriculture & Foods, Forests and Fisheries. At the Fisheries Division, Aquaculture Research and Development Section (highlighted in red colour in the organization chart above) is responsible for monitoring aquaculture activities which comply to Aquaculture Act 2003 and Fisheries Act 2002.
The Fisheries Management Act 2002 and the Aquaculture Management Regulations 2008 are the main legislations that regulate fisheries activities within Tonga is administered by the Fisheries Division as part of the Ministry of Agriculture & Foods, Forests and Fisheries (MAFFF).The Fisheries Division is responsible for conserving, monitoring and managing fisheries resources in a sustainable manner. However, the Aquaculture Management Act 2003 and Regulations 2008 are also under the Fisheries executive power, but the primary focus is on potential aquaculture commodities and culture methods proposed by any applicant for aquaculture licences in any Tonga coastal waters.
The research activities in Tonga rely totally on foreign donors, especially from regional organizations such as SPC or FAO; training is included with participation in workshops, conferences and attachments both on national and international levels.
Aquaculture activities are quite new to Tonga and require high investment with a slow rate of returns which contributes to the lack of large-scale commercial activities existing in Tonga. On the other hand, aquaculture is treated locally as a long-term and a somewhat risky investment in comparison with agriculture goods leading to the reluctant support of the local banks to finance their aquaculture activities (i.e. pearl farming).
A few areas that have been highlighted for development for the half pearls ‘MABE’ industry include a need to establish the local farms internationally in a way to improve or increase the income for the pearl farmers. Subsequently, there is still room for improvement to be made by capacity building for farmers with further training in areas such as grafting techniques, seeding and farm management.
Annual report 2008. Ministry of Agriculture & Foods, Forests and Fisheries – Fisheries Division Unpiblished data), Tonga.
Aquaculture Research and Development Section Database, 2011. Ministry of Agriculture Foods, Forests & Fisheries Division. Tonga.
Fa’anunu, ‘U., Fale, P., Paongo, ‘O., Taholo, L., Kawaguchi, M., 1994. Mullet fry collection along cosatl areas of Tongatapu. Fisheries Research Bulletin of Tonga V 1: 1-6.
Ngaluafe, P.,2009. Tonga Aquaculture Profile. Aquauclture Research and Development Section, MAFFF, Tonga (unpublished Data).