Effects of feeding pit formation by rays on an intertidal meiobenthic community

The purpose of this study was to determine effects of feeding pit formation by rays on benthic meiofauna communities in an estuarine intertidal sand f lat. Core samples were collected both inside and outside feeding pits on fo ur different dates during the summer of 1998, and were dominated by nematod es. Regardless of sampling date, the total number of meiofauna and the domi nant meiobenthic component (nematodes) were always higher outside pits than inside pits. The total number of meiofauna in the control areas (outside p its) exceeded 300 cm(-2) and steadily declined over the study period. The d ecline in numbers may have been due to continued excavation and reworking o f the sediments as well as other uncontrolled factors. Statistically signif icant differences between treatments also occurred for ostracods on the fir st three sampling dates, and for oligochaetes on the first two sampling dat es. There were no significant differences in numbers of copepods or polycha etes for any of the sampling dates of the study; however, densities were lo w. Preliminary data suggest that the low numbers of meiofauna in pits is ma intained for at least 2 days after formation. (C) 2000 Academic Press.