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This section describes the preparation of seeds for release, site selection, transplantation, and monitoring and management strategies for introduced marine snails.

4.1 Tagging and Measuring Green Snail Seeds

The 2-year-old green snails of about 5-cm diameter were collected from the rearing tanks in preparation for seed release in the wild. This size snail is recommended as it has better protection from predators. The shells were cleaned dry with a piece of cloth. A tag number was stuck to the outer shell near the base with super glue to prevent the tag number from being removed while in the field. After tagging, shell height and shell width were recorded; such information will be used later in the monitoring (Plate 32).

Plate 32

Plate 32.

4.2 Site Survey

Before the transplantation is carried out, it is vital to do field surveys to check the quality of the area for transplantation. The area must have the following criteria (Kikutani, personal communication).

4.2.1 Algal cover

Algae, particularly the brown and red turf algae, are essential as food for the seeds. Rich algae cover is the first consideration of an area as a transplantation site.

4.2.2 Current, tides and wind direction

These physical parameters of the sea are very important later for the seeds. Current and wind direction will be responsible for the spread of the incoming generations the seeds. Incoming tides also transport the young ones to other areas, thus enhancing distribution.

4.2.3 Bottom topography

A good reef is necessary also for successful transplantation. It should be complex, with many crevices where the young can hide for protection from predators, and have a well-developed fore-reef slope for adults (Plate 33).

Plate 33

Plate 33.

4.3 Transplantation Procedures

After the survey of the transplantation sites, the tagged shells will be placed into a container and transported to the site by boat. A group of divers will take the seeds to the reef bottom and place them individually in crevices and other structures where they can be protected from predators, strong waves and reef gleaners.

4.4 Monitoring and Recovery Methods

Transplantation of seeds is not enough if there is no data on their survival, dispersion rate and growth rate. It is recommended that monitoring should be standardized and the process to recover the shells requires that operators have good free diving and SCUBA skills to be able to collect sufficient data. The following table could be a useful guide in the monitoring and recovery process.

Time periodActivityRemarks
0 monthRelease seedsNo. of seeds released
1 monthCheck survival and algae distribution% Survival
12-month survey1) Check survival, dispersion rate, and growth rate% S, % DR and % GR
2) New tag and release
24-month surveyCheck survival, dispersion rate, and growth rate% S, % DRand% GR
36-month surveyCheck survival, dispersion rate, and growth rate% S, % DR and % GR

* S-Survival
DR-Dispersion rate
GR-Growth rate

4.5 Management Strategies

Engaging local people in the process is vital to the success of introduced marine snail management. People should feel that these introduced shells are for their and their children's use. To this end, the public should be made fully aware of this farming process, and these activities should be community based.

4.5.1 Public Awareness

If local people fully understand the purpose of introducing marine snails to their reefs, they will be more likely to participate for the success of the management schemes, and poaching could be prevented. Information dissemination is essential, so prior to the transplantation, a series of public awareness programs should be conducted like seminars in different areas. Also, mass media like television, radio and newspapers should be used (Plate 34).

Plate 34

Plate 34. From MATANGI TONGA January–March 1997.

4.5.2 Community-Based Management After the public awareness programs are complete, the community where the shells will be introduced should be given intensive lectures and workshops on how to handle these shells. This process is aimed to promote better understanding and to let the people in the community do the releasing, protecting, and daily monitoring of the seeds. In this way, community members will assist in the management of the introduced species (Plate 35).

Plate 35

Plate 35.

4.5.3 Genetic Diversity for Broodstock

Parent shells in different combinations ensure gene variety, and should be considered with great care. (Yamakawa, personal communication). Genetic diversity should be managed carefully by seeding many parent shells, selecting appropriate release locations, and managing the resources wisely.

Many parent shells should be seeded for the following reasons.

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