Population Ecology of Crocodylus porosus at Kuching Wetland National Park, Human-Crocodile Conflict and Management Plan for Crocodile in Sarawak, 2016-2020, Sarawak, Malaysia (Borneo)

The Estuarine Crocodile (Crocodylus porosus) is one of the world’s most well-known crocodile species, as it is one of the largest of present-day reptiles, and a macro-predator of large mammals. It inhabits both marine and freshwater habitats. Crocodiles are a living link with the dinosaur-like reptiles of prehistoric times and are the nearest living relatives of birds, and have been in existence for the past 200 million years. Crocodiles loom large in human imagination and perceptions amongst many local communities in Sarawak. Without a better understanding on the nature, biology and ecology of crocodiles, these perceptions can create antagonistic attitude towards the species. Better understanding of crocodiles would also allow improved management of the species. Estuarine Crocodile has been widely studied elsewhere, but in Sarawak, Malaysia, have been limited. In Sarawak, the species is protected under Wild Life Protection Ordinance, 1998 and has been down-listed to CITES Appendix II, allowing trade of the species taken from the wild. Thus a study on ecology of the species in Kuching Wetland National Park (KWNP), an analysis on possible factors that lead to increase in Human-Crocodile Conflict in Sarawak and the introduction of a Management Plan for the species within the State for a period from 2016 until 2020 were conducted. The study was aimed at investigating its habitat use within the Park, to test for effect of forest cover, tidal and lunar cycles on its activities, abundance and distribution within the area. The study also aimed to determine population structure and dietary preference of the species, particularly juveniles. On the other hand, the aims of the Human-Crocodile Conflict analysis are to identify factors associated with attacks, and to address the issues while the introduction of the management plan aims to reduce conflict, guiding the Government and the general public on sustainable management of crocodile and assure returns for local communities and the State of Sarawak iv from commercialization of the species. The study shows that all four size classes of the Estuarine Crocodiles inhabit the Park all year round, with a peak of its breeding season in the months of August and September, indicating that KWNP is of Type-I habitat for the species. Clearing of mangrove forests along Sungai Lemidin Besar and Sungai Lemidin Kecil affects distribution, abundance and activities of hatchlings along the rivers, as the area could no longer support food supplies for hatchlings and nesting materials for adults. Conversely, the absence of forest cover and vegetation do not affect activities of adult crocodiles. Activity pattern of the species in KWNP was not significantly affected by lunar cycles, though adults seemed to be more wary towards humans during bright moon-lit nights. Tide levels also did not seem to affect activities of all size classes of the species. The study also shows that Estuarine Crocodiles in KWNP were not evenly distributed along rivers, but tend to congregate at parts of the Park, presumably with greater food sources and forest cover. Analysis on Human-Crocodile Conflict shows that most of the attacks over the last 23 years were associated with activities of its victims such as bathing, wading or fishing in rivers during late afternoons or at dusk. Though Estuarine Crocodiles are predators and opportunistic feeders, the attacks that occur at dusk might be due to mistaken identity for monkeys. The implementation of the management plan for crocodile in Sarawak has the potential to reduce the rate of crocodile attacks on humans while at the same time would ensure sustainable management of the species in the State. Keyword: Macro-predator, antagonistic attitude, prehistoric time, habitat, lunar cycl