Successfully cultured and reared coral embryos from wild caught spawn slick in the Philippines

摘要

Various coral propagation techniques, including utilization of spawn slicks, have been developed to help restore degraded coral communities. Although, it has been demonstrated that embryos from spawn can be used for sexual propagation of corals, few have quantified fertilization, survival, settlement, post-settlement mortality, and long term survival of transplanted corals, grown from spawn slick. Spawn slicks were collected at night off Anda, northwestern Philippines, following a mass spawning of Acropora spp. The collected spawn, which contained similar to 4,100,000 developing embryos, was highly viable (96% actively dividing) at 12 h post-mixing. Based on assays, 2-day old larvae exhibited high survival in culture (87.9%), and subsequent settlement competency (92%). All 3330 settlement substrates (coral plug-ins), seeded with approximately 2,100,000 3-day old coral larvae, had at least one settled coral after one month. Forty-five pieces of these plug-ins, which were randomly tagged, had settled coral spats ranging from 3 to 88 spats per plug-in (26.7 +/- 3.4 spats per plug-in, mean +/- SE). Two and four months after the initial settlement on plug-ins, 76.3 +/- 1.2% and 42.5 +/- 1.2% of the spats survived, respectively. Two hundred seventy (270) coral plug-ins were then transplanted at six sites. Transplanted corals exhibited varying survival in different sites, from 11 to 62%, five months post-transplantation. Thirty-one months post-transplantation, only two of the six sites had surviving transplanted corals, i.e., four colonies of Acropora millepora, three A. divaricata, and one A. cf. austera. However, setbacks in the survival of transplants highlight the need to further examine drivers affecting long term performance of coral transplants, which is vital in establishing different generations of parent colonies that can be used for sustainable mariculture of corals.