Abstract
Hong Kong's coastal waters afford a marginal environment for coral reef growth, with high seasonal and short-term variability in water temperatures (ranging from < 14="" degrees="" c="" in="" winter="" to="" 31="" degrees="" c="" in="" summer),="" and="" low="" summer="" salinity="" (as="" low="" as="" 15="" psu)="" due="" to="" runoff="" associated="" with="" the="" asian="" wet="" monsoon="" season="" and="" the="" pearl="" river="" delta.="" yet="" hong="" kong="" hosts="" 84="" reef-building="" coral="" species="" in="" 28="" genera="" of="" 12="" families="" of="" the="" scleractinia,="" distributed="" in="" 5="" broad="" communities="" with="" strong="" geographic="" and="" environmental="" affinities="" and="" key="" indicator="" species.="" coral="" communities="" farthest="" from="" the="" influence="" of="" the="" pearl="" river="" delta="" have="" relatively="" high="" sea="" bed="" coverage="" and="" species="" diversity="" (30="" to="" 50%="" coverage,="" and=""> 30 spp. per site), and also host some large, old corals. X-radiographs of a core of one massive Porites colony confirms similar to 200 yr of growth, with 2 short-term periods of mortality, hidden in the skeleton by overgrowth. Very low linear extension rates (< 4="" mm="" yr(-1))="" in="" this="" coral="" and="" 2="" others="" are="" anomalous="" for="" porites="" corals="" and="" are="" indicative="" of="" the="" high-stress="" environment.="" low="" growth="" rates="" suggest="" that="" other="" hong="" kong="" corals,="" despite="" the="" harsh="" environmental="" conditions,="" may="" also="" live="" for="" centuries,="" contributing="" to="" the="" development="" of="" 'incipient="">