Understanding dietary differences in Indian dugongs through opportunistic gut sampling of stranded individuals

Abstract

We analysed gut samples of stranded dugongs from Tamil Nadu and Gujarat, India, to understand their die - tary preferences. We quantified seagrass fragments from the gut as leaf, stem and rhizome, and identified leaf fragments up to genera level by their morphological features and epidermal cell characteristics using an inverted microscope. The overall abundance of above-ground fragments (leaf, stem) was higher in all samples , which may suggest the dugongs use a cropping mechanism to forage. The ingested seagrass generic diversity was higher in Tamil Nadu ( n = 5) dugong individuals than those in Gujarat ( n = 2). A total of five genera were recorded from all samples, viz. Halophila spp., Halodule spp., Cymodocea spp., Enhalus sp. and Syringodium spp. In Tamil Nadu, Cymodocea spp. (46.24%) was the most dominant, followed by Halophila spp. (26.49%), Syringodium spp. (14.83%) and Halodule spp. (12.16%), with a low occurrence of Enhalus spp. (0.19%). In Gujarat, Halodule spp. (61.48%) was the most dominant, followed by Halophila spp. (30.20%). The recorded plastic and wood fragments suggest fine spatial scale threat mapping in dugong habitats.