We are pleased to announce the publication of our newest Open Access article on using small drones for photo-identification of Antillean manatees in Endangered Species Research titled “Using small drones to photo-identify Antillean manatees: a novel method for monitoring an endangered marine mammal in the Caribbean Sea.”
The article is part of the ESR Special: Drones in Conservation.
ABSTRACT
Population assessments and species monitoring for many endangered marine megafauna are limited by the challenges of identifying and tracking individuals that live underwater in remote and sometimes inaccessible areas. Manatees can acquire scars from watercraft injury and other incidences that can be used to identify individuals. Here we describe a novel method for photo-identification of Antillean manatees Trichechus manatus manatus using aerial imagery captured during flights with a small multirotor drone. Between 2016 and 2017, we conducted 103 flights to detect and observe manatees in Belize, primarily at St. George’s Caye (SGC) near the Belize Barrier Reef. Review of aerial videos from these flights resulted in 279 sightings of manatees (245 adults, 34 calves). High-resolution images of individual manatees were extracted and classified according to image quality and distinctiveness of individual manatees for photo-identification. High-quality images of manatees classified as sufficiently distinctive were used to create a catalog of 17 identifiable individuals. At SGC, 21% of all sighted adult manatees (N = 214) were considered photo-identifiable over time. We suggest that the method can be used for investigating individual site fidelity, habitat use, and behavior of manatee populations. Our photo-identification protocol has the potential to improve long-term monitoring of Antillean manatees in Belize and can be applied throughout clear, shallow waters in the Caribbean and elsewhere.
The article can be found at the following link:
Cite this article as: Landeo-Yauri SS, Ramos EA, Castelblanco-Martínez DN, Niño-Torres CA, Searle L (2020) Using small drones to photo-identify Antillean manatees: a novel method for monitoring an endangered marine mammal in the Caribbean Sea. Endang Species Res 41:79-90.
If you have any questions or want to discuss our research please contact the corresponding author Sarah Landeo-Yauri:
sslandeo@gmail.com
Cheers,
*****************************
Eric Angel Ramos
Ph. D. Candidate in Animal Behavior & Comparative Psychology
The Graduate Center, City University of New York
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Today's Topics:
1. new publication on whale temporomandibular joint (Alex Werth)
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Message: 1
Date: Fri, 31 Jan 2020 20:38:21 +0000
From: Alex Werth <awerth@hsc.edu>
To: "marmam@lists.uvic.ca" <marmam@lists.uvic.ca>
Subject: [MARMAM] new publication on whale temporomandibular joint
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<DM5PR0801MB3829EB644B2F7A1FF650333AC5070@DM5PR0801MB3829.namprd08.prod.outlook.com>
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On behalf of my colleagues (Haruka Ito and Keiichi Ueda) I am pleased to announce the publication of our new article in the Journal of Morphology on whale feeding and TMJ motion:
https://onlinelibrary.wiley.com/journal/10974687
Werth, A.J., H. Ito, and K. Ueda. Multiaxial movements at the minke whale temporomandibular joint. Journal of Morphology, 2020;1?11. https://doi.org/10.1002/
jmor.21107
Abstract: Mandibular mobility accompanying gape change in Northern and Antarctic minke whales was investigated by manipulating jaws of carcasses, recording jaw movements via digital instruments (inclinometers, accelerometers, and goniometers), and examining osteological and soft tissue movements via computed tomography (CT)?scans. We investigated longitudinal (?) rotation of the mandible and mediolateral displacement at the symphysis (?1) and temporomandibular joint (?2) as the mouth opened (?). Results indicated three phases of jaw opening. In the first phase, as gape increased from zero to 8?, there was slight (<1?) ? and ? rotation. As gape increased between 20 and 30?, the mandibles rotated slightly laterally (Mean 3?), the posterior condyles were slightly medially displaced (Mean 4?), and the anterior ends at the symphysis were laterally displaced (Mean 3?). In the third phase of jaw opening, from 30? to full (?90?) gape, these motions reversed: mandibles rotated medial!
ly (Mean 29?), condyles were laterally displaced (Mean 14?), and symphyseal ends were medially displaced (Mean 1?). Movements were observed during jaw manipulation and analyzed with CT?images that confirmed quantitative inclinometer/accelerometer data, including the unstable intermediate (Phase 2) position. Together these shifting movements maintain a constant distance for adductor muscles stretched between the skull's temporal fossa and mandible's coronoid process. Mandibular rotation enlarges the buccal cavity's volume as much as 36%, likely to improve prey capture in rorqual lunge feeding; it may strengthen and stabilize jaw opening or closure, perhaps via a simple locking or unlocking mechanism. Rotated lips may brace baleen racks during filtration. Mandibular movements may serve a proprioceptive mechanosensory function, perhaps via the symphyseal organ, to guide prey engulfment and water expulsion for filtration.
Best regards,
Alex
_______________________________
Alexander J. Werth, Ph.D.
Trinkle Professor of Biology
Hampden-Sydney College
Box 162, Hampden-Sydney, VA 23943
434-223-6326, fax 434-223-6374
http://www.hsc.edu/alex-werth
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