When fragmented coral spawn? Effect of size and timing on survivorship and fecundity of fragmentation in Acropora formosa
- 493 Downloads
In order to determine competency of sexual reproduction and survival rate after fragmentation, the branching coral Acropora formosa was fragmented and fragments in three different sizes (ca. 5, 10 and 20 cm long) and three different stages of gametogenesis were transplanted on coral pavement. Their oocyte development and fecundity, as well as spawning were monitored for a 3-year period. The oocyte development was affected by both fragment size and by the developmental stage of oocytes when fragmented. In small fragments, the oocytes were resorbed while in large fragments they continued development. Oocytes in the early vitellogenic stage at the time of fragmentation were resorbed, whereas those in the late stage continued developing. Smaller fragments showed a lower survival rate and histological observations of their gonads revealed resorption of oocytes, suggesting that there was a trade-off of energy between reproduction and survival. Transplanted fragments often spawned one month earlier than the donor colonies in the first year, but spawning occurred in the same month as the donors or did not occur at all in the second year and none spawned in the third year. The risk of colony death may cause the fragments to re-allocate energy for sexual reproduction.
KeywordsSexual Reproduction Small Fragment Large Fragment Oocyte Development Eosinophilic Granule
We are grateful to K. Shimoike, S. Hosaka and the staff members of Akajima Marine Science Laboratory for their kind help, T. Kokita for assisting statistical analysis.
- Bryant D, Burke L, McManus J, Spalding M (1998) Reefs at risk: a map-based indicator of threats to the world’s coral reefs. World Resources Institute, Washington, DCGoogle Scholar
- Fautin DG, Mariscal RN (1991) Cnidaria: Anthozoa. In: Harrison FW, Westfall JA (eds) Placozoa, Porifera, Cnidaria and Ctenophora. Microscopic anatomy of invertebrates, Book 2, Wiley-Liss, Inc., New York, pp 267–358Google Scholar
- Harriott VJ, Fisk DA (1988) Coral transplantation as a reef management option. In: Proceedings of the 6th international coral reef symposium, vol 2. Australia, pp 375–379Google Scholar
- Kojis BL, Quinn NJ (1985) Puberty in Goniastrea favulus: Age or size limited? In: Gabrie C, Salvat B (eds) Proceedings of the 5th international coral reef symposium, vol 4. Moorea, French Polynesia, Antenne Museum-EPHE, pp 289–293Google Scholar
- Nonaka M, Baird AH, Kamiki T, Yamamoto HH (2003) Reseeding the reefs of Okinawa with the larvae of captive-bred corals. Coral Reefs 22:34Google Scholar
- Okubo N (2004) Transplantation of coral fragments: Acropora formosa. In: Omori M, Fujiwara S (eds) Manual for restoration and remediation of coral reefs, Nature Conservation Bureau, Ministry of the Environment, Japan, pp 62–67Google Scholar