Seasonal changes in recruitment of Pteria penguin in North Queensland, Australia

Abstract

Spat recruitment of the winged pearl oyster Pteria penguin, in relation to season, substrate type, and depth was investigated at Orpheus Island in north Queensland for 27 mo, from February 2008 to April 2010. Two substrate types (70% shade cloth and open-weave polypropylene mesh bags) were deployed at 2 depths (4 m and 6 m) and checked every 6 wk for 3 spawning seasons to determine any differences in quantity of spatfall between these factors. No significant difference was found in spat recruitment between substrate types (P = 0.158) or depth (P = 0.349), although there was a significant seasonal effect on spat recruitment (P < 0.001), with a peak in the quantity of spatfall in late summer, from February to March, and no spat collected in the winter to spring (July to October). Maximum settlement of spat was 10.2 spat per mesh bag collector in February 2008. Recruitment was significantly reduced (P < 0.001) during the 2010 spawning season as a result of disturbance from severe storms generated by tropical cyclone Olga in late January.