Enhancing the livelihood benefits of a new village-based fishery in Samoa

Snail Trochus bundle for sale


Few foreign introductions of animals have had overwhelming benefits to people with little ecological impact. In Australia, we are grateful for the honey bee. In Samoa, over one thousand village-based fishers and their families are thankful for the recent introduction of a marine snail, called ‘trochus’. With an 80-year history of beneficial introductions in other Pacific Islands, this humble snail was a clear choice for boosting subsistence seafood production and income generation for coastal villages around Samoa’s two main islands. SCU was recently commissioned by the Australian Centre for International Agricultural Research (ACIAR) to assess the extent of the socioeconomic impacts.

Trochus is non-harmful to other reef animals and feeds on algae, which was taking over reefs in Samoa since the recent coral bleaching events. Traditionally, trochus was harvested in western-Pacific islands for the export of its thick shell, used in handicrafts and button manufacturing. The flesh can also be eaten locally.

From 2003 to 2006, Samoa’s Ministry of Agriculture and Fisheries (MAF) introduced live trochus snails to reefs in Samoa, through expertise and funding from ACIAR. Fifteen years on, the extent of population establishment and socioeconomic impacts arising were still largely unknown. Fishers were using only the flesh and not realising the full economic value from the shells through value-adding. MAF has not yet allowed exports of trochus, in part because information about the fishery was incomplete; therefore, the full economic value of the animal in Samoa has been largely under-exploited.

This research project (2018-2019) aimed to understand the extent of the trochus colonisation on reefs in Samoa and the factors affecting the fishers’ capture of trochus. In addition the project aimed to assess the socioeconomic impacts of the trochus fishery, build capacity in value-adding of shells and to appraise the potential for sustainable exports.

Snails participants with machines make jewellery from trochus

  • Ministry of Agriculture and Fisheries (MAF) through improved knowledge of the distribution and stocks of trochus that will inform resource management
  • ACIAR – through an indication of the return on investment from the previous translocation project
  • Fisher communities through learning new skills (working with shells) and opportunity for increased income
  • Female fishers through greater involvement and empowerment

Seafood production benefits from the introduction of trochus have been massive in Samoa. An underlying reason for the huge impact to subsistence consumption is that the local species of reef snails are much smaller and were naturally not very abundant to all for plentiful harvests. Trochus, on the other hand, is about twice as large as the native species and, once well established, can become abundant enough that it can be harvested in large volumes without overfishing the resource.

At least 1,030 village-based ‘artisanal’ fishers in Samoa are now harvesting trochus regularly. Both women and men harvest the animals, usually along with other reef seafood. Women were just as efficient in harvesting trochus, and earned similar income to men, with respect to their fishing frequency. The project found that more than two-thirds of all fishers eat the trochus themselves and share part of the catch within their villages. For a majority of the fishers who harvest trochus, these introduced snails now represent their most, or second-most, important seafood in their overall catch volume. The new resource has, therefore, diversified seafood significantly.

Almost two-thirds of fishers were selling part, or all, of their trochus catch, usually in bottles by the roadside or in local markets. For those fishers, the sale of trochus flesh now represents 17% of their overall gross income from all sources. One fisher wrote, “we prefer the introduced trochus because it is bigger than the native topshell and makes it easier to fill a bottle to sell”. Four out of five fishers surveyed said that they were satisfied or very satisfied with income from this new fishery.

The project coordinated four week-long capacity-building workshops to train people from more than 30 coastal villages in techniques for using the trochus shells to make jewellery and handicrafts. “I am very thankful for this workshop. I’ve learnt new skills of how to produce jewelleries and marketing”, one new artisan wrote. The local market for such shell products is strong, and there was great interest from vendors. The project bought specialized equipment for shell polishing and jewellery making, which was left in Samoa for the new artisans to use in future.

An economic assessment showed that the income from fishery has already greatly exceeded the initial investment to introduce trochus, through Australia’s foreign-aid program.  Sales of trochus meat are generating an estimated AU$800,000 annually to village fishers.

The project provided a Policy Brief to government ministers and fishery managers. One recommendation was that women should have an equal representation in decision-making about fishery management, since they also harvested trochus and it represents a large proportion of their catch. The fishery has a modest carbon footprint, so the present use of traditional canoes should continue to be encouraged. Income from the fishery could almost double if fishers are allowed to export the largest shells.

The ecological data gave no indication of negative impacts to the reef ecosystem. Native snails were no less common at sites where trochus have become abundant, and trochus do not appear to be harming corals. In fact, their feeding on algae could help to minimise its overgrowth since the coral bleaching events, which could help corals to rebound.

This research work (2018-2019) was funded by the Australian Centre for International Agricultural Research (ACIAR) through project FIS/2016/128, in collaboration with the fishery officers of the Fishery Division of MAF and statisticians at the University of Wollongong. The project operated through funding of $467,000.

The project collected both ecological and socioeconomic data to offer an objective assessment of impacts of the new trochus fishery. Underwater visual surveys by the project researchers showed that the trochus had colonised beyond the initial translocation sites sufficiently to support a subsistence fishery including shell exports. A graduate-student project showed the specific habitat features favoured by trochus, which will guide future translocation initiatives in the Indo-Pacific region.

Hands-on training workshops held on both main islands were used to build technical capacity in jewellery and handicraft making. Participants made jewellery such as necklaces and earrings and were keen to continue this an alternative livelihood.

Questionnaire-based interviews of 303 fishers from 34 villages provided the socioeconomic data for assessing the extent of fishing, consumption, sale and trade of trochus. The project used state-of-the-art ‘linear mixed effects model’ statistical analyses to examine gender effects in the fishery and factors that lead to greater incomes. Fishers using boats to access the fishing grounds were shown to reap greater economic benefits.

The project data, together with estimates of the number of fishers in coastal villages, were used to assess the potential volume and value of the shell that could be sustainably exported from Samoa. Approximately 260 tonnes of shell are harvested annually and currently discarded since exports are not allowed.

The project also reviewed the management plan for the fishery, set to be implemented soon. The new regulations include size limits, daytime collection only, an option of a seasonal closure on harvests and export licences (if allowed).