Sexual reproduction and the early life history of Montipora capitata in Kane'ohe Bay, O'ahu, Hawai'i

The larval biology, early life history and energetic costs of sexual reproduction in the scleractinian coral Montipora capitata were assessed in Kane'ohe Bay, O`ahu, Hawai`i. Larvae were competent to settle three days post-spawning (DPS), and settled in large pulses days after syngamy in the laboratory and field. Ability to settle remained high (83% proportional settlement) at six weeks, but was reduced (≤11%) at 56 plus days. A few larvae survived and settled at 191 and 207 DPS, the longest lengths of competency recorded for a scleractinian coral. The larvae settled equally well on a variety of substrates including different species of crustose coralline algae and rubble covered with filamentous algae. Tests with antibiotics suggested bacteria play a role in inducing settlement.; The early life histories of Montipora capitata (hermaphroditic broadcast spawner), Porites compressa (gonochoric broadcast spawner) and Pocillopora damicornis (brooder) were monitored on field settlement plates. Montipora capitata had the highest number of overall settlers (91% of nearly 20,000 settlers), but displayed significantly lower levels of survivorship and growth than P. compressa and P. damicornis. Each species displayed Type III survivorship. The mean estimated time for settlers to reach 1 cm2 projected area in the field was 4.9 years for M. capitata and 1.7 years for P. compressa and P. damicornis. Survival was not related to growth in M. capitata, in contrast to the other two species. These three species differ in their fertilization and early life history strategies. Montipora capitata emphasizes processes that achieve large quantities of larvae and settlers, while P. compressa and P. damicornis appear more dependent on settler quality (survival and growth).; The mean percent of annual net photosynthetic productivity allocated to sexual reproduction in Montipora capitata was estimated as 2.13% for shallow reef-flat colonies and 3.50% for deeper reef-slope colonies. This energy expenditure could be replaced by excess colony photosynthesis within two to six weeks (depending on depth) following summertime spawning. Montipora capitata may gain its early life history advantage through large repetitive, low cost, influxes of larvae settling in a variety of habitats. Management implications are discussed.