The present study examined the digestibility of eelgrass based on dry weight and energy by captive dugongs Dugong dugon in relation to the nutritional content of the eelgrass and the feeding parameters of the dugongs. Digestibility was calculated on the basis that food retention by captive dugongs is 144-168 hours. Digestibility of eelgrass was strongly affected by the lignin content of the eelgrass species concerned, with a negative correlation between the apparent digestibility of a species and its lignin content. Since fiber contents are higher in seagrasses, including eelgrasses, than in terrestrial plants on which mammalian herbivores typically feed, the apparent digestibility reported from captive dugongs in the present study indicate that eelgrass may have an extraordinarily high digestibility.
2003 The Mammalogical Society of Japan