DIET PREFERENCE AND ACTIVITY OF ASIAN WATER MONITOR AT CHAGAR HUTANG TURTLE SANCTUARY

Abstract

Excessive sea turtle nest predation is a problem for conservation management of sea turtle populations. For green turtles (Chelonia mydas) nesting at Chagar Hutang beach, Redang Island in Malaysia, Asian water monitor lizards (Varanus salvator) are nest predator. To help deter water monitors from attacking nest, plastic mesh is placed on top of sea turtle nests, although this is not always successful in preventing predation. Due to human food waste is frequently dumped near sea turtle nesting area, no studies have documented the if Asian water monitor lizards are attracted by human food waste at Chagar Hutang beach. This study assessed the prevalence of Asian water monitors on the sea turtle nesting beach using passive track-count plots (2×1m) every 50 m along the beach 5-10 m above the high tide mark in the area used by sea turtles to construct their nests. Results indicated Asian water monitors were the only vertebrate nest predator at Chagar Hutang and were widely distributed along the beach and had a Passive Activity Index (PAI) of 1.25. The stomach contents of 20 Asian water monitors were examined by stomach flushing, and 76.8% of stomach contents were human food wastes, 21.2% were turtle egg and hatchling and only 1% were from other natural food sources. This study suggests human food waste attract Asian water monitor to Chagar Hutang beach and that this may result in water monitors visiting sea turtle nests at a higher rate compared to a situation if human food waste was not available.