AN ABSTRACT OF THE THESIS OF John Ralph McClung II for the degree of Master of Science in Wildlife Science presented on March 9, 2017. Title: Photo-identification of Melon-headed Whales (Peponocephala electra) in the Marquesas Islands: Creation of the First Photo-identification Catalog and Estimation of Group Size and Minimum Abundance in a Remote Archipelago Abstract approved: ________________________________________________________ C. Scott Baker For many species of oceanic dolphins, photo-identification and genetic data indicate that these island-associated populations are demographically isolated from pelagic populations and that island-associated populations exhibit very different patterns of movement and habitat use. Melon-headed whales (Peponocephala electra) are generally considered a pelagic dolphin, but have been documented around oceanic islands where deep water occurs close to shore. In the main Hawaiian Islands, for example, analysis of ten years of photo-identification data shows that melon-headed whales form a relatively small and apparently isolated population. Melon-headed whales have also been documented around several islands in the Marquesas archipelago of French Polynesia, but no information on their population structure in the islands exists. To better understand this population of melon-headed whale, I analyzed over 6,000 photographs collected during Expedition Marquesas, a series of small-boat sampling surveys conducted around six islands – Hiva Oa, Tahuata, Mohotani, Ua Huka, Ua Pou and Nuku Hiva – in March and April of 2012. Photographs and biopsy samples were collected during 14 encounters with melon-headed whales at four of the islands; Mohotani, Ua Huka, Ua Pou, and Nuku Hiva. In this thesis, I compiled the first photo-identification catalog for melon-headed whales in the islands by analyzing photographs to identify individual dolphins based on distinctive markings to their dorsal fins (referred to as distinctively marked individuals or DMIs). In total, 393 DMIs were identified and sightings were reconciled within encounters, between encounters, and between islands to construct sighting histories for each DMI. This information was then used to improve upon visual counts of the number of individuals in encountered groups, to investigate inter-island movement of DMIs, and to provide a minimum abundance of melon-headed whales in the islands. Estimates of the number of individuals in resting groups were obtained by incorporating information on the number of quality images of each DMI and the total number of quality non-DMI images collected within an encounter into the Poisson log- normal mark-resight model (PNE). The PNE estimates were then compared to visual counts of the number of melon-headed whales in encountered groups obtained by observers in the field. Using the PNE to estimate group size is novel since most studies determine group size by estimating the number of visible individuals. Investigations into the accuracy of observer estimates have found that estimates can vary widely between observers and tend to underestimate group size, especially as group size increases. Here, I found that the sizes of resting groups in the Marquesas Islands were large (median = 458) and that, on average, the mark-resight model estimated the true group size to be 1.5 times greater than the visual counts. By comparing sightings of DMIs between islands, I found evidence of limited movement of DMIs between the surveyed islands. Eight DMIs first seen at Ua Pou were resighted from 3 to 13 days later at Nuku Hiva, a distance of approximately 50 kilometers. No DMIs first documented at Mohotani or Ua Huka were resighted at any of the other islands. While the short time between surveys limits the conclusions that can be made, these results suggest an interesting pattern of habitat use within the islands, especially given the similar distance between encounters at Ua Huka and Nuku Hiva. The minimum abundance of melon-headed whales in the Marquesas Islands was estimated using the Lincoln-Petersen, two-sample, mark-recapture model. I first compared DMI images from pairs of resting-group encounters at each island to identify resightings of DMIs between encounters. Information on the number of DMI images per encounter and the number of DMIs seen in the first encounter and subsequently resighted in the second encounter were incorporated into the model to derive an estimate of the total number of DMIs for each island. Since only information on DMIs was incorporated into the model, the minimum abundance at each island was calculated by adjusting the estimate of the total number of DMIs by the proportion of quality DMI images in each data set. The minimum abundance at each island ranged from 300 (95% CL 188-412; CV = 0.19) at Ua Pou to 631 (95% CL 475-788; CV = 0.13) at Mohotani. Summing the estimates obtained at each island resulted in a minimum abundance estimate of 1,785 (95% CL 1506-2065; CV = 0.36) melon-headed whales in the Marquesas Islands during the study period. The establishment of the first melon-headed whale photo-identification catalog for melon-headed whales in the Marquesas Islands lays a foundation for future investigation into the population structure of this enigmatic species in the islands. The waters around the Marquesas Islands supports a diverse marine community, including several species of small cetaceans, and represents an area of high productivity in an otherwise oligotrophic region of the South Pacific. French Polynesia has taken steps to protect this important habitat by designating the entirety of the French Polynesia EEZ as a Marine Mammal Sanctuary and by petitioning UNESCO to designate the Marquesas Islands as a World Heritage Site. The baseline information provided by this thesis is an important step in understanding the population structure and habitat use of melon-headed whales – information crucial to effective conservation of this species in the Marquesas Islands. ã Copyright by John Ralph McClung II March 9, 2017 All Rights Reserved Photo-identification of Melon-headed Whales (Peponocephala electra) in the Marquesas Islands: Creation of the First Photo-identification Catalog and Estimation of Group Size and Minimum Abundance in a Remote Archipelago by John Ralph McClung II A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science Presented March 9, 2017 Commencement June 2017 Master of Science thesis of John Ralph McClung II presented on March 9, 2017. APPROVED: ________________________________________________________________ Major professor, representing Wildlife Science ________________________________________________________________ Head of the Department of Fisheries and Wildlife ________________________________________________________________ Dean of the Graduate School I understand that my thesis will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my thesis to any reader upon request. ________________________________________________________________ John Ralph McClung II, Author ACKNOWLEDGEMENTS I would like to express my appreciation to the faculty and staff at OSU’s Hatfield Marine Science Center and all those in OSU’s Department of Fisheries and Wildlife. Your consistent optimism and selfless support kept me going. This thesis would not have been possible without several Graduate Teaching Assistantships, often outside my area of focus, that not only paid my tuition but also supported my eating habit. Project funding was also provided by the Ministry of the Environment of French Polynesia, the South Pacific Whale Research Consortium, and from the Pew Marine Conservation fellowship to C. S. Baker for ‘A pattern of dolphins’, or aPOD, a study of insular populations in the Pacific. Thanks also to my advisor, C. Scott Baker. You set me on my course and offered encouragement when I needed it most. I doubted myself many times but you always provided focus and direction when I wanted to abandon ship. Thank you also for taking me on as a student employee so I could finish my last term. And a special thank you to the people of the United States. Without the support provided by the Post 9-11 GI Bill, this thesis would not have been possible. I only hope that I may live long enough to see that access to free, or at least affordable, education is available to all Americans. I would also like to express my gratitude to my graduate committee, Drs. Julia Jones, Daniel Palacios, and Emily Shroyer. I truly appreciate your comments and perspectives that challenged me to step outside my own little bubble and think within a broader context. Your flexibility and patience made completion of this project possible. Data for this project was collected during Expedition Marquesas, a series of small-boat surveys of cetaceans conducted in March and April of 2012 around six islands. Special thanks to M. Michael Poole whose decades of research of cetaceans and efforts to ensure their conservation in French Polynesia made this work possible. Michael collected and provided the data for this thesis and was willing to support someone he’s never met. Thanks Michael. May we meet soon. Also, my appreciation to Marc Oremus, Renee Albertson, and Scott Baker for conducting the surveys and collecting the data that forms the backbone of this thesis. I would also like to thank Robin Baird, Jessica Aschettino, and Sabre Mahaffy from Cascadia Research Collective. You freely shared your