The reproductive biology of the scleractinian coral Plesiastrea versipora in Sydney Harbour, Australia

Abstract

The scleractinian coral Plesiastrea versipora occurs throughout most of the IndoPacific; however, the species is only abundant in temperate regions, including Sydney Harbour, in New South Wales, Australia, where it can be the dominant sessile organism over small spatial scales. Population genetics indicates that the Sydney Harbour population is highly isolated, suggesting long-term persistence will depend upon on the local production of recruits. To determine the potential role of sexual reproduction in population persistence, we examined a number of features of the reproductive biology of P. versipora for the first time, including the sexual system, the length of the gametogenetic cycles and size-specific fecundity. P. versipora was gonochoric, supporting recent molecular work removing the species from the Family Merulinidae, in which the species are exclusively hermaphroditic. The oogenic cycle was between 13 and 14 mo and the spermatogenetic cycle between 7 and 8 mo, with broadcast spawning inferred to occur in either January or February. Colony sex was strongly influenced by colony size: the probability of being male increased with colony area. The longer oogenic cycle suggests that females are investing energy in reproduction rather than growth, and consequently, males are on average larger for a given age. Alternatively, colonies may change sex from female to male as they grow. In contrast, per polyp fecundity did not vary with colony size. We conclude that the Sydney Harbour population is reproductively active and therefore has the potential to maintain current levels of abundance even without an external supply of propagules.

Coral reproduction at Hall Bank, a high latitude coral assemblage in Western Australia

“…2d). These data suggest that, similar to populations on the east coast of Australia (Madsen et al 2014), the oogenic cycle lasts longer than 1 yr.…”

Sexual production of corals for reef restoration in the Anthropocene

“…Gametes develop within or attached to mesenteries that contain oocytes and/or spermatocytes and progress through 4 stages, over several months or more (I−IV; e.g. Szmant-Froelich et al 1980, Szmant-Froelich 1985, Harrison & Wallace 1990, Glynn et al 1991, Madsen et al 2014. Oocytes (top row of inner cycle) begin as enlarging interstitial cells adjacent to, or within, the mesenterial mesoglea (Stage I;Madsen et al 2014), and slowly accumulate cytoplasm around the nucleus (Stage II).…”

Coral reproduction on the world’s southernmost reef at Lord Howe Island, Australia

“…comm.). The reproductive bio logy of high-latitude corals, such as those on Lord Howe Island, is of particular interest, because these populations are often geographically isolated (Noreen et al 2009) and therefore replenishment is likely to be highly dependent on local reproductive output or irregular input of propagules from distant upstream reefs (Fellegara et al 2013, Madsen et al 2014.…”