TITLE:
How many donor colonies should be cross-fertilized for nursery farming of sexually propagated corals?
AUTHORS:
Kenji Iwao, Naohisa Wada, Aki Ohdera, Makoto Omori
KEYWORDS:
Acropora, Coral Farming, Coral Reefs, Gamete Fertilization, Genetic Diversity, Reef Rehabilitation
JOURNAL NAME:
Natural Resources,
Vol.5 No.10,
July
31,
2014
ABSTRACT:
Coral reef
restoration approaches have often utilized adult colonies as sources for
fragments (i.e. clones) to be
transplanted. Although restoration through this method is fast and cheap, it
has been pointed out that it may reduce genetic diversity of the restored
population. Low genetic diversity is a concern for reef restoration when seed
fragments are raised asexually from only a few donor colonies. This can lead to
lower fertilization rates among seed fragments, and reducing the longterm
benefits of reef restoration in particular areas. Additionally, low genetic
diversity can compound the effects of increased ocean temperature and other
environmental stressors, further jeopardizing the health of a reef. An
alternative approach through sexually propagated coral cultures and out-plantings
can alleviate this problem. Sexually produced offsprings are more genetically
diverse. They can be produced in far greater numbers than coral fragments and
do not imply destructive methods. Ongoing research at the Akajima Marine
Science Laboratory in Okinawa, Japan has helped to improve the production and
maintenance of sexually propagated larval cultures. Our results show that
crosses between gametes from 6 or more colonies will provide the highest
fertilization rate (>95%). Based on the results, we suggest the use of 6 or
more donor colonies for practical gamete fertilization in sexually derived
coral culture.