Dont poop where you eat: Location of sea cucumber egesta in a coral reef environment
Conference Paper
Overview
Overview
abstract
Coral reefs are in decline worldwide due to multiple factors including pollution, increased water temperatures and increased sediment loads. The purpose of this study was to determine if the sea cucumber Pearsonothuria graeffei removes silt deposits from coral through its feeding activities and if such removal is negated by their defecation of egesta residue onto coral. These sea cucumbers removed more than 60% of flocculent sediment on which they fed from live coral. Pearsonothuria graeffei were found on live coral significantly more than on any other substrate. Live coral comprised 40% of the substrate directly under the sea cucumbers feeding tentacles and 29% of the substrate under the animals bodies; both were significantly greater than the amount of live coral (16%) in the research area. Conversely, only 2.5% of the substrate underneath defecated egesta was live coral; the majority of substrate under egesta was dead coral rubble (80%), which made up approximately 30% of the research area. Pearsonothuria graeffei primarily feeds on sediment occurring on live coral such that their feeding activities may reduce sediment loads to nonlethal levels. However, even though they preferentially occur and feed on live coral, these sea cucumbers are somehow choosing to defecate on dead coral rubble rather than redepositing sediment on live coral. In summary, P. graeffei do not poop where they eat!
