Factors influencing the density and morphometrics of the cup coral Caryophyllia smithii in Lough Hyne

Populations of Caryophyllia smithii were studied at three sites of differin g sedimentation regime in Lough Hyne, Ireland. The height, length, width an d density of individuals were measured along with the depth of accumulated sediment on the rock substratum at each site. Calyx size was largest at the site of least sedimentation and smallest at the site of most sedimentation . In contrast, height of individuals was greatest at the site of most sedim entation and smallest at the site of least sedimentation. The height of ind ividuals was correlated with the level of surrounding sediment (Pearson's c orrelation 0.836 P<0.05). The uppermost limit of C. smithii corresponded wi th the downward limit of the infralittoral zone at each site; 15, 13, and 1 2 m at the low, mid and highly sedimented site respectively. Density averag ed over depth was greatest (70 ind m(-2)) at the site of moderate sedimenta tion and lowest (13 ind m(-2)) at the site of least sedimentation. Density was also found to increase with depth at the sites of moderate and high sed imentation.