Flux of barnacleplate fragments and fecal pellets measured by sediment traps

Comparison of the flux of broken barnacle plates from a caged living barnacle community
(0.8 g mˉ² dayˉ¹) with a similar but uncaged barnacle community nearby (30 g mˉ² dayˉ¹) suggests that
feeding activity by the sheepshead, a predatory sparid fish, is the chief fragmenter of barnacle plates
caught in 2 x 2.2 m traps. Sediment recovered from an uncaged trap suspended under a floating dock
contained four components. The individual fluxes of these components for the period June
1979-January 1980 was barnacle plates 4-46 g mˉ² dayˉ¹, fragments of the encrusting barnacle
community 0-3. quartz sand 1-4, and mud in the form of barnacle fecal pellets 0.3-7. Summed up, these
materials yield a layer of sediment 8-16 mm thick each year. The flux of broken plates varied from a peak
in late September to a low in December-January, probably due to migration of sheepshead out of the
study area during spawning. Quartz sand found in the traps was shown to be transported by mullet.