Search for a command to run...
ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 8:249-257 (2009) - DOI: https://doi.org/10.3354/esr00232 Detection of free-ranging West Indian manatees Trichechus manatus using side-scan sonar Daniel Gonzalez-Socoloske1,3,*, Leon D. Olivera-Gomez2, Robert E. Ford1,4 1Dept. of Earth and Biological Sciences, Loma Linda University, 11065 Campus Street, Loma Linda, California 92350, USA 2División Académica de Ciencias Biológicas, Universidad Juárez Autónoma de Tabasco, Carretera Villahermosa-Cardenas Km 0.5, C.P. 86150, Villahermosa, Tabasco, Mexico 3Present address: University Program in Ecology, Duke University, PO Box 90329, Durham, North Carolina 27708, USA 4Present address: Center for GIS Training and Remote Sensing, National University of Rwanda, PO Box 212, Huye, Rwanda *Email: dg52@duke.edu ABSTRACT: Turbid and tannin-stained waterways are difficult habitats to study and present problems with respect to the management of aquatic fauna, and especially of endangered and cryptic animals such as manatees Trichechus spp. Linnaeus. Throughout much of the range of the extant trichechid species (T. inunguis, T. manatus, and T. senegalensis), the scientific approaches that are used successfully to document the status of the Florida subspecies (T. m. latirostris) are not feasible, due either to constraints associated with habitat or to the high costs involved. We examined the use of side-scan sonar as a novel way to acoustically detect free-ranging West Indian manatees (T. m. latirostris and T. m. manatus), and evaluated the effectiveness of the technology under various environmental conditions. Blind transects, where one observer only looked at the sonar, were conducted in Mexico and Florida to confirm that manatees could be detected and to determine a preliminary manatee detection rate for the sonar unit. Quality sonar images were produced under most environmental conditions examined, provided that ambient water movement was low. Manatees were successfully detected laterally up to 18 m, and the best acoustic images were produced when the animals were stationary and oriented parallel to the boat. Preliminary detection was 81 and 93% in Florida and Mexico, respectively. We conclude that over limited areas, and under certain environmental conditions, side-scan sonar is a cost-effective option to accurately detect manatees and provide important information for conservation decisions. Like all survey techniques, it has limitations, but its unique advantages will be a welcomed alternative to aerial surveys and visual boat surveys of opaque waterways. KEY WORDS: Acoustic detection · Manatees · Turbid waterways · Trichechus manatus · Side-scan sonar · Florida · Mexico · Honduras Full text in pdf format Supplementary appendix PreviousCite this article as: Gonzalez-Socoloske D, Olivera-Gomez LD, Ford RE (2009) Detection of free-ranging West Indian manatees Trichechus manatus using side-scan sonar. Endang Species Res 8:249-257. https://doi.org/10.3354/esr00232 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 8, No. 3. Online publication date: October 16, 2009 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2009 Inter-Research.