Hi all, A PDF copy of my Masters thesis on Irrawaddy dolphins (*Orcaella brevirostris*) in Sarawak, Malaysia is available. Peter, C. 2012. Distribution patterns, habitat characteristics and population estimates of Irrawaddy dolphins (Orcaella brevirostris) in Kuching Bay, Sarawak. Msc Thesis. Insitute of Biodiversity and Environmental Conservation. Universiti Malaysia Sarawak. 120pp. ABSTRACT: Irrawaddy dolphins (*Orcaella brevirostris*) are known to be riverine and coastal dwelling animals which place them under pressure from human activities like fishing, coastal developments and environmental pollution. Previously, there was a lack of baseline information on the population of Irrawaddy dolphins that are present in Kuching Bay. This lack of data impeded conservation and management efforts, as no one could determine how many dolphins there are, how they are distributed on a fine scale, or what their preferred habitat characteristics are. In order to overcome this, small boat surveys were conducted in the Kuching Bay from June 2008-September 2010. The first objective of the study aimed to map the distribution patterns and determine the relative abundance of Irrawaddy dolphins in the waters of Kuching Bay. Surveys covered a total of 4,091 km and 317 hours. Irrawaddy dolphins were sighted 41 times on-effort representing an estimated total of 183 individuals. The mean encounter rate throughout the 44 days of survey was 0.30 sightings per hour. Analysis of encounter rates within 2km by 2km grid cells showed high densities of Irrawaddy dolphins in the Salak estuary, Bako peninsula and offshore of Telaga Air. The second objective was to define the habitat preferences of Irrawaddy dolphins by conducting water parameter samplings and measuring the physical characteristics of the sighting sites. Kruskal-Wallis U tests showed that the animals’ distributions are not significantly related to water temperature, pH, depth or distance to land. However the dolphin distribution was statistically significant for the different categories of salinity (p < 0.05) and distance to rivermouth (p < 0.05). Fisher’s exact test indicated that Irrawaddy dolphins are statistically more likely to be present in waters within a 6 km radius from rivermouths. Dolphins’ distributions are also affected by tide levels as Mann-Whitney U tests proved a statistically significant difference (p < 0.05) in dolphin distribution between tide levels lower than 2.0 m and tide levels higher than 2.0 m. The third objective of the study was to obtain absolute abundance estimates of Irrawaddy dolphins in Kuching Bay. This was achieved by using mark-recapture techniques on photo-identified individuals to generate population estimates for the Kuching study area. Based on this, the best estimate of the Irrawaddy dolphin population in Kuching Bay is 233 dolphins (CV = 22.5%, 95% CI 151-360). The fourth objective was to learn about the individual movement patterns of the Irrawaddy dolphins in Kuching Bay by identifying individual dolphins through photo-identification and plotting the observed locations of identified individuals. Seventeen individuals were photographed more than once and four individuals were photographed in both the Salak–Santubong and Bako–Buntal bays on a few occasions. The furthest distance an individual dolphin traveled between sighting locations in the study was approximately 40 km. In addition, resighted individuals were photographed across different survey months as well as different survey years. This study showed that the Irrawaddy dolphins of Kuching Bay prefer areas of lower salinity, closer to land and rivermouths, with tidal state also playing a significant role in their distribution. The estimate obtained in this study showed that the population in Kuching Bay is relatively small and the movement patterns analysis proved that several individual dolphins utilize both the Salak-Santubong Bay and Bako-Buntal Bay. Therefore, any management or conservation efforts for the Irrawaddy dolphins will need to be applied to both bays. Please let me know if you are interested in reading it and I will send a copy. Best Regards, Cindy Peter -- Cindy Peter, MSc (Marine Ecology) Sarawak Dolphin Project Institute of Biodiversity and Environmental Conservation University Malaysia Sarawak www.ibec.unimas.my/SDP2008