Diet of Dugongs: Are They Omnivores?

Abstract

Fecal analysis revealed that although dugongs (Dugong dugon) from Moreton Bay in subtropical Australia fed primarily on seagrasses, ascidians were an important part of their diet. Ascidians occurred in 73% of 48 fecal samples, accounting for 26% of their wet weight. Dugongs fed deliberately on both small stalked colonial ascidians that carpeted the substrate and on larger solitary ascidians. One dugong had fed selectively on a gregarious polychaete. In tropical areas, dugongs consumed invertebrates only incidentally with sea-grasses. Nutritional stress caused by seasonality in abundance of seagrasses may explain the omnivory of the Moreton Bay animals, which live at the southern edge of the dugong's range.