'Establishing a mini hatchery for giant clams and sandfish monitoring on Maiana Island' June 2020
June 29 2020: A team of four officials from the Aquaculture Unit in Coastal Fisheries, Tanaea has returned from a one-week trip to Maiana to research establishing a mini-hatchery for giant clams, and to monitor populations of sandfish and clams.
A highly prized food source, giant clams have been declining in abundance over the years. Harvesting hatchery-reared clams is more sustainable than harvesting wild clams. Hatcheries support the diversification of clams for livelihoods and economic activities.
The team identified Tebwangetua village as the ideal site for a mini hatchery due to a passage a few meters out on the reef flat enabling the collection of fresh seawater required.
As part of the trip, the team also monitored Tematantongo, Aobike, and Tebwanga for sandfishes and found that all the villages’ pens were destroyed, likely related to wave action. The team also concluded that low community involvement in safeguarding the pens contributed to the issue.
The team then checked on 300 giant clams that were deployed in May last year – 200 at Bubutei and 100 in Tebikerai – finding a high mortality in both sites. According to monitoring in 2019, only three were found to have died from Bubutei village, however the team found that the mortality rate has increased dramatically, with only 12 surviving in Bubutei and eight in Tebikerai. In Tebikerai, the plates were seen sitting on top of each other crushing the clams below them. This may be the result of waves during storms, as well as a poor monitoring of the pens by communities.
To increase the chance of sandfishes’ survival, the team recommended there should be a large release of bigger size fish in one spot per island. Further, there must be frequent monitoring of the pens by Fisheries Extension Assistants and the Hatchery team from Tanaea.
The team also recommended that the selection of one or two households from selected communities to engage in clam farming will lead to improved monitoring and will increase the sense of unity with Fisheries in harvesting clams. Emphasising the financial incentives to farmers to sell their clams will also help ensure the success of the hatcheries.
The survey mirrors one conducted last year on Abemama island.
The trip was financially made possible by the project ‘Enhancing National Food Security in the Context of Climate Change’, commonly known as ‘LDCF-1’, funded by the Global Environment Facility- Least Developed Countries Fund through the United Nations Development Programme and managed by the Environment and Conservation Division under the Ministry of Environment, Lands and Agricultural Development.