54 SEPTEMBER 2019 • WORLD AQUACULTURE • WWW.WAS.ORG 1987). Rapid growth in human populations along coastlines during the last century have resulted in substantial impacts to intertidal marine environments, especially coral reefs (Brander et al. 2010). The size range of harvested Pacific clams in South Tarawa, Republic of Kiribati, appears to be well below the maximum size attained by the species, perhaps as a result of overharvesting (Paulay 2000). There are no previous studies on the feasibility of culturing this species. The implementation of small-scale rural aquaculture of Pacific clams may be an interesting option for improving household food security and supplementing family income of the rural poor. Even at a subsistence level, this type of aquaculture provides much needed animal protein food and substantial cash income from the sale of the surplus crop. The Marshall Islands Aquaculture Laboratory of the College of the Marshall Islands Cooperative Research and Extension Land Grant Program is located in Arrak, at the western tip of Majuro atoll. The main objective of the aquaculture research program is to evaluate potential species for aquaculture production, develop the basic technology for culturing them to meet demand for seafood, food security and stock enhancement, encouraging and helping farmers and fishing communities to improve their socioeconomic condition and quality of life by making improvements to their farming practices, resulting in increased production and income; providing safe, sustainable seafood and supporting healthy ocean populations and ecosystems. The particular objectives of the research on Pacific clam are to: 1) Obtain basic biological data by identifying the different developmental stages until the juvenile phase. 2) Test the feasibility of seed production in captivity and grow-out culture, conducting bioassays for establishing successful spawning and optimization of larval growth and survival. 3) Compare growth and survival of adult clams on natural tidal flats and in the laboratory. 4) Determine their nutritional value. Pacific clam specimens were periodically collected from lagoon sand flats along Majuro atoll (Fig. 3). Temperature, salinity and tidal height were recorded at each site. Individuals were sampled by excavating plots to a depth of 30 cm and sieving the substrate through a 1-cm mesh. After transport to the laboratory, length, height, depth and total weight of clams were measured (Fig. 4). Animals selected for studies of reproduction, feeding and growth at the laboratory were maintained in 200-L seawater tanks (Fig. 5), the ones used for growth comparison buried in sand in 1/8” mesh bags (Fig. 6). The main outcomes obtained to date were: • Induction of spawning: Successful attempts to spawn Pacific clam were made by removing mature animals from the water and air drying for two hours during the full moon. • Larval life cycle determination and larval rearing: Eggs FIGURE 4. Shell length measurement. FIGURE 3. Specimen collection from lagoon sand flats. FIGURE 5. Feeding Pacific clams with microalgae at the laboratory. FIGURE 6. Ongrowing in mesh bags buried in sand.
RkJQdWJsaXNoZXIy MjExNDY=