Coral reproduction in a high-latitude, marginal reef environment (Moreton Bay, south-east Queensland, Australia) Invertebrate Reproduction and Development

Numerous factors are hypothesised to limit the geographical distribution of reef organisms, such as corals. For example, high-latitude populations of some marine invertebrates are not reproductive, rather they are sustained by the input of larvae from reefs closer to the tropics. Here, we investigate the reproductive biology of high-latitude corals in Moreton Bay, Australia, to test whether or not these populations have the capacity to be self-sustaining. The reproductive condition of 21 scleractinian species was determined in November and December 2002 and 2003 and January 2004. Seventy percent of colonies (n = 97) were gravid and at least one gravid colony was found in 86% of the species, suggesting that reproductive activity is concentrated in late spring and summer. Mature colonies were present in all three months and immature colonies were present in January, indicating a reproductive season of at least four months. The proportion of mature colonies was highest in January (42%) suggesting a peak in reproductive activity at this time. Coral populations of Moreton Bay clearly have the potential to be self-sustaining; however, their isolation from other reef areas suggests that these populations may be slow to recover from disturbance