Heeding the History of Kahu Manō: Developing and Validating a Pono Photo-Identification Methodology for Tiger Sharks (Galeocerdo cuvier) in Hawaiʻi

dc.contributor.advisor Grabowski, Tim
dc.contributor.author Nakachi, Kaikea
dc.contributor.department Tropical Conservation Biology & Environmental Science
dc.date.accessioned 2022-02-01T18:43:23Z
dc.date.available 2022-02-01T18:43:23Z
dc.date.issued 2021-12
dc.description.degree M.S.
dc.identifier.uri http://hdl.handle.net/10790/6865
dc.subject Conservation biology
dc.subject Natural resource management
dc.subject Hawaiʻi
dc.subject Photo-Identification
dc.subject Shark
dc.title Heeding the History of Kahu Manō: Developing and Validating a Pono Photo-Identification Methodology for Tiger Sharks (Galeocerdo cuvier) in Hawaiʻi
dc.type Thesis
dcterms.abstract Amidst concurrent global declines in shark populations and advancements in camera technology, underwater photo-identification (photo-ID) is increasingly being used to unobtrusively gather data on potentially sensitive species. Tiger sharks (Galeocerdo cuvier) are prime photo-ID candidates, particularly in places where population data is scarce and they hold a significant role in customary practices and beliefs, such as Hawaiʻi. This study emulates traditional Hawaiian practices of kahu manō, i.e., shark keepers, through implementation of non-intrusive contemporary approaches to develop, assess, and validate photo-ID methodology as a pono, or respectfully appropriate, technique for tiger shark research in Hawaiʻi. An identification system reliant on chronologically subdividing the dataset based on sex and caudal fin condition and then using 14 identifiable traits to match unknown tiger sharks to a database of previously sighted individuals was developed. This identification system complements Native Hawaiian approaches of observation and anaylsis, such as kilo and the papakū makawalu process developed by the Edith Kanakaʻole Foundation. Volunteers with varying experience with tiger sharks and photo-ID, were trained to use this identification system and exhibited > 90% agreement in tiger shark ID with each other and the method developer. The time taken by an observer to identify an individual negatively influenced the probability of agreement with other observers, including the expert observer. In contrast, observer-reported certainty positively influenced the probability of agreement. This validated method was used to ID individual tiger sharks (n=69) in West Hawaiʻi during 2005-2021, including the observation of 1 male shark and 1 female shark across 16 years. This study identifies important parameters of photo-ID that can aid future photo-ID experimental design and demonstrates the capacity for safe and respectful research methods that parallel Native Hawaiian cultural practices. The validation of underwater photo-ID methodology contributes an important non-invasive approach to research and inform management in Hawaiʻi, and its continued implementation and accompanying analyses as pono scientific techniques have the potential to obtain meaningful life-history information on an important ecological and cultural species.
dcterms.extent 64 pages
dcterms.language en
dcterms.publisher University of Hawaii at Hilo
dcterms.rights All UHH dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
dcterms.type Text
local.identifier.alturi http://dissertations.umi.com/hilo.hawaii:10217
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