Temporal patterns of coral cover in the offshore Pilbara, Western Australia

Abstract

Patterns of hard coral cover and benthic composition were assessed at seven sites around Barrow Island in the Pilbara region of Western Australia between 2008 and 2013. While the per cent hard coral cover around Barrow Island was relatively stable between 2009 and 2012, there was a 69.3 % proportional change in hard coral cover between 2012 and 2013. Concomitant with this decline, Principle Coordinates Analysis showed a shift towards turf/coralline algae and there was a reduction in the proportion of the Acroporidae and a relative increase in the proportion of the Poritidae at most sites. During early 2013, sea surface temperatures around Barrow Island rose above seasonal averages, reaching 7.4 °C-weeks (degree heating weeks) from late February 2013 to mid-April 2013, and the decline in hard coral cover and shifts in benthic composition appear to be related to mortality associated with a coral bleaching event in early 2013.