Fig. 2. Water quality around inshore reefs in PC and WT, displayed by a principal components analysis biplot. The water quality vectors point towards the location with highest concentrations (abbreviations are listed in Section 2). The vector of the water quality index (WQI, dashed line) is strongly associated with reefs of the WT. The WT and PC reefs are represented by black and grey thermometer symbols, respectively, with the fill of each symbol representing the water quality index of each reef. Concentrations of all particulate matter (suspended solids, particulate phosphorus and nitrogen, chlorophyll and phaeopigments) were highest at Alexandra Reef and lowest at Hannah Reef, whereas concentrations of silicate and lowest salinity were highest at Normanby Reef and High Island.