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Asian Journal of Agriculture and Development (AJAD) - Call for papers!

Reproduction of Coral Pocillopora damicornis (Linnaeus) at Panjang Island, Central Java, Indonesia

(Indonesia), Doctor of Philosophy in Marine Biology (Gadjah Mada University)

Dissertation Abstract:

 

This study was designed to investigate the reproduction period, reproductive effort, and recruitment rate of coral Pocillopora damicornis in the southern and northern sides of Panjang Island, Central Java. Reproduction period was determined by observing gametogenesis, embryogenesis, and planulation (planulae release) period, while reproductive effort was estimated by measuring polyp fecundity and larval production in each colony. Recruitment rate of the coral was determined by the density of juvenile in the field.

Results showed that reproductive effort and recruitment rate of coral P. damicornis between the southern and northern sides of Panjang Island were different. Reproduction period was not different between the sides while reproductive activities occurred every month throughout the year. Planulation occurred from new moon to full moon with gamete maturation in full moon and third quarter moon, indicating that planulation was controlled by gametogenesis cycle and influenced by the interaction between tide and lunar. The multiple gametonic cycles resulted double peaks planulation in a single colony while planulation in paired colony revealed single peak, indicating that variation in planulation period was due to adaptation of gametonic cycles controlled by the existence of other colonies. Reproductive effort varied seasonally with polyp fecundity and larval production increasing during southeast monsoon and decreasing in northwest monsoon. The annual fluctuations in reproduction were controlled by the interaction of water temperature, photoperiod (day length), nutrients, and rainfall. Reproductive effort was different between the southern and northern sides, probably in response to reduced number of productive polyp in the northern side, which was influenced by high wave frequency and wave height. High larval production in southern side, which was trapped by the turbulent eddies current caused high recruitment in this side; however, it revealed low survival rate of juvenile. Recruitment was characterized by high mortality of juvenile in the early settlement period and high abundance of juvenile under surfaces of settlement plates, which was influenced by sediment accumulation. High recruitment occurred around their parental colonies and seemed to correspond to adult distribution. It was suggested that coral P. damicornis population be maintained by internal recruitment.