Burrowing Rates of Lithotrya Dorsalis (Cirripedia: Thoracica) in Jamaica

Lithotrya dorsalis is a member ofthe only genus of thoracic an barnacles known to burrow in carbonate rock. It is a prominent component of high energy, low intertidal communities in the tropics. Burrowing rates of this barnacle were estimated for a relatively small size class. A relationship was established between area of the characteristic oval aperture and burrow volume after the animal was removed. Subsequently, over a 31-month period, at either 7- or 12-month intervals, burrow apertures of living animals were photographed and measured. Volumes of carbonate material excavated over these time intervals were then extrapolated from the previously established aperture area to burrow volume relationship. Based on the observed size frequency distribution, three size classes of animals within this sample were established. These classes burrowed at significantly different rates. The average volume of carbonate material excavated within each size category (small-intermediate-large) over a 12-month period was estimated to be 0.14, 0.18, and 0.27 cm³, respectively. At an average density of 1 barnacle cm⁻², this is equivalent to an erosion of the carbonate substrate at rates of 2.72, 3.38, and 5.11 kg˙m⁻² ˙yr⁻¹.