Abundance and demographic parameters of spinner dolphins (Stenella longirostris subsp.) off Oʻahu's Waiʻanae Coast

Simple item page
dc.contributor.advisor Bejder, Lars
dc.contributor.author McPherson, Liah Laila
dc.contributor.department Marine Biology
dc.date.accessioned 2024-03-11T22:20:13Z
dc.date.available 2024-03-11T22:20:13Z
dc.date.issued 2023
dc.description.degree M.S.
dc.identifier.uri https://hdl.handle.net/10125/108016
dc.subject Conservation biology
dc.subject Biology
dc.subject Wildlife conservation
dc.subject abundance
dc.subject age-structure
dc.subject conservation
dc.subject emigration
dc.subject spinner dolphins
dc.subject survival
dc.title Abundance and demographic parameters of spinner dolphins (Stenella longirostris subsp.) off Oʻahu's Waiʻanae Coast
dc.type Thesis
dcterms.abstract The occurrence and behavior of spinner dolphins (Stenella longirostris subsp.) off Waiʻanae, Oʻahu are well-described, yet a data deficit on their abundance and trajectory hinders effective conservation. This study employed multi-state open robust design (MSORD) modelling to estimate seasonal dolphin abundance, apparent survival, and temporary emigration, and further-developed a method for age-structure quantification via unoccupied aerial system (UAS; drone) photogrammetry. Dolphin photo-identification and UAS data were collected between April 2021 and January 2023 off the Waiʻanae Coast. Abundance varied seasonally, ranging from 140 (± 36.8 SE) to 373 (± 60.0) individuals and was lowest during Winter. Apparent survival was high and constant (0.95 ± 0.02 SE) and temporary emigration was Markovian. Seasonal environmental variability and spinner dolphin reproductive biology may drive patterns of abundance and temporary emigration. A crude estimate of total abundance for spinner dolphins documented off Waiʻanae (N = 550) is comparable to a recent island-wide abundance estimate, suggesting that the Waiʻanae Coast is a candidate site for long-term monitoring of Oʻahu spinner dolphins. UAS data analysis showed that the total length of spinner dolphins can be effectively estimated by measurements of the blowhole to dorsal fin distance. As age-length growth curves do not exist for the subspecies of spinner dolphin in Hawaiʻi, age was estimated using a growth curve for a related subspecies. Additional life-history information about Hawaiian spinner dolphins will allow both the use of a more accurate growth curve, and an assessment of population health. This work provides the first systematic estimates of abundance and demographic parameters for spinner dolphins off Waiʻanae, imparting valuable information for monitoring and management decisions.
dcterms.extent 77 pages
dcterms.language en
dcterms.publisher University of Hawai'i at Manoa
dcterms.rights All UHM 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/hawii:11906
Files
Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
McPherson_hawii_0085O_11906.pdf
Size:
4.39 MB
Format:
Adobe Portable Document Format
Description:
Download
Collections
M.S. - Marine Biology