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Siegfried TR, Reimer J, Roberto E, Noren C, Vidal A, Dixon K, DuBois M, Piacenza SE. Size-Mediated Sea Turtle Behavioral Responses at Artificial Habitats in the Northern Gulf of Mexico. Animals (Basel) 2022; 13:ani13010114. [PMID: 36611724 PMCID: PMC9817786 DOI: 10.3390/ani13010114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/24/2022] [Accepted: 12/26/2022] [Indexed: 12/29/2022] Open
Abstract
Our understanding of size-specific sea turtle behavior has lagged due to methodological limitations. However, stereo-video cameras (SVC) are an in-water approach that can link body-size and allow for relatively undisturbed behavioral observations. In this study, we conducted SVC dive surveys at local artificial reefs, piers, and jetties in the northern Gulf of Mexico (nGOM) from May 2019 to August 2021. Using SVCs, we measured sea turtle straight carapace length, documented behaviors, and quantified wariness by assessing minimum approach distance (MAD). In green sea turtles (Chelonia mydas), the observed MAD ranged from 0.72 to 5.99 m (mean 2.10 m ± 1.10 standard deviation (SD), n = 73). For loggerhead sea turtles (Caretta caretta), the MAD ranged between 0.93 and 3.80 m (mean 2.12 m ± 0.99 SD, n = 16). Kemp's ridley sea turtles (Lepidochelys kempii) were similar to loggerheads, and MAD ranged from 0.78 to 3.63 m (mean 2.35 m ± 0.99 SD, n = 8). We then evaluated what biological factors could impact the MAD observed by species, but we excluded Kemp's ridleys as the sample size was small. Using a linear mixed model and model selection based on AICc, the top ranked model for both green and loggerhead sea turtles included SCL as the most important factor influencing MAD. MAD did not vary with habitat type for either species. Our results showed that larger individuals, regardless of species, have a greater wariness response, becoming startled at greater distances than smaller individuals. The findings of our study support the use of SVC as an accessible, non-invasive tool to conduct ecologically relevant in-water surveys of sea turtles to link behavioral observations to body size.
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Affiliation(s)
| | - Jackson Reimer
- Department of Biology, University of West Florida, Pensacola, FL 32514, USA
| | - Emma Roberto
- Department of Biology, University of West Florida, Pensacola, FL 32514, USA
| | - Christopher Noren
- Department of Biology, University of West Florida, Pensacola, FL 32514, USA
- Darling Marine Center, University of Maine, Walpole, ME 04573, USA
| | - Alex Vidal
- Department of Biology, University of West Florida, Pensacola, FL 32514, USA
- United States Fish and Wildlife Service, Maryland Fish and Wildlife Conservation Office, Annapolis, MD 21401, USA
| | - Kristi Dixon
- Department of Biology, University of West Florida, Pensacola, FL 32514, USA
| | - Morgan DuBois
- Department of Biology, University of West Florida, Pensacola, FL 32514, USA
| | - Susan E. Piacenza
- Department of Biology, University of West Florida, Pensacola, FL 32514, USA
- Department of Fisheries, Wildlife and Conservation Sciences, Oregon State University, Corvallis, OR 97331, USA
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Siegfried TR, Fuentes MMPB, Ware M, Robinson NJ, Roberto E, Piacenza JR, Piacenza SE. Validating the use of stereo-video cameras to conduct remote measurements of sea turtles. Ecol Evol 2021; 11:8226-8237. [PMID: 34188882 PMCID: PMC8216940 DOI: 10.1002/ece3.7653] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/08/2021] [Accepted: 04/20/2021] [Indexed: 11/10/2022] Open
Abstract
Point 1: Stereo-video camera systems (SVCSs) are a promising tool to remotely measure body size of wild animals without the need for animal handling. Here, we assessed the accuracy of SVCSs for measuring straight carapace length (SCL) of sea turtles. Point 2: To achieve this, we hand captured and measured 63 juvenile, subadult, and adult sea turtles across three species: greens, Chelonia mydas (n = 52); loggerheads, Caretta caretta (n = 8); and Kemp's ridley, Lepidochelys kempii (n = 3) in the waters off Eleuthera, The Bahamas and Crystal River, Florida, USA, between May and November 2019. Upon release, we filmed these individuals with the SVCS. We performed photogrammetric analysis to extract stereo SCL measurements (eSCL), which were then compared to the (manual) capture measurements (mSCL). Point 3: mSCL ranged from 25.9 to 89.2 cm, while eSCL ranged from 24.7 to 91.4 cm. Mean percent bias of eSCL ranged from -0.61% (±0.11 SE) to -4.46% (±0.31 SE) across all species and locations. We statistically analyzed potential drivers of measurement error, including distance of the turtle to the SVCS, turtle angle, image quality, turtle size, capture location, and species. Point 4: Using a linear mixed effects model, we found that the distance between the turtle and the SVCS was the primary factor influencing measurement error. Our research suggests that stereo-video technology enables high-quality measurements of sea turtle body size collected in situ without the need for hand-capturing individuals. This study contributes to the growing knowledge base that SVCS are accurate for body size measurements independent of taxonomic clade.
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Affiliation(s)
| | | | - Matthew Ware
- Department of Earth Ocean and Atmospheric ScienceFlorida State UniversityTallahasseeFLUSA
| | - Nathan J. Robinson
- Fundacion OceanogràficOceanogràfic de ValènciaValenciaSpain
- Cape Eleuthera Island SchoolCape Eleuthera InstituteEleutheraThe Bahamas
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Harvey-Carroll J, Stewart JD, Carroll D, Mohamed B, Shameel I, Zareer IH, Araujo G, Rees R. The impact of injury on apparent survival of whale sharks (Rhincodon typus) in South Ari Atoll Marine Protected Area, Maldives. Sci Rep 2021; 11:937. [PMID: 33441580 PMCID: PMC7806644 DOI: 10.1038/s41598-020-79101-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 12/04/2020] [Indexed: 01/29/2023] Open
Abstract
The whale shark (Rhincodon typus) is an endangered species with a declining global population. The South Ari Atoll Marine Protected Area (SAMPA), Maldives, is one of few locations globally where year-long residency of individuals occurs. This SAMPA aggregation appears to consist almost exclusively of immature males. Due to its year-round residency, this local aggregation is subjected to a high degree of tourism pressure. This ecotourism contributes to the high level of interest and protection offered to whale sharks by the local community. Unfortunately, if regulations are not followed or enforced, tourism can bring with it major stressors, such as accidental injuries. We used POPAN capture-mark-recapture models and lagged identification rate analysis to assess the effect of major injuries on whale shark residency within SAMPA. Injuries may be obtained outside SAMPA. We found individuals with major injuries had a higher apparent survival in the area than those without. Lagged identification rates also demonstrated that sharks with major injuries are more likely to return to the area. We suggest that major injuries result in sharks prolonging their time in the developmental habitat. These findings have implications for individual fitness and the population viability of this endangered species. We propose targeted conservation strategies be considered to protect sharks from further injury. Based on the presented spatio-temporal distributions of sharks, and current local knowledge of sighting patterns, speed limit zones and propeller-exclusion zones should be implemented and enforced. If carried out alongside tourist education, these measures will contribute to the protection of whale sharks within SAMPA and beyond. Furthermore, our results can aid research direction, alongside regulation and enforcement development, at similar sites worldwide.
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Affiliation(s)
- Jessica Harvey-Carroll
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives ,grid.11914.3c0000 0001 0721 1626School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
| | | | - Daire Carroll
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives ,grid.43641.340000 0001 1014 6626The James Hutton Institute, Dundee, UK ,grid.7372.10000 0000 8809 1613The University of Warwick, School of Life Science, Coventry, UK
| | - Basith Mohamed
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives
| | - Ibrahim Shameel
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives
| | | | - Gonzalo Araujo
- Large Marine Vertebrates Research Institute Philippines, Cagulada Compound, 6308 Jagna, Bohol Philippines
| | - Richard Rees
- Maldives Whale Shark Research Programme (MWSRP), South Ari Atoll, Maldives
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Araujo G, Miranda JA, Allen HL, Labaja J, Snow S, Ponzo A, Legaspi CG. Whale sharks Rhincodon typus get cleaned by the blue-streak cleaner wrasse Labroides dimidiatus and the moon wrasse Thalassoma lunare in the Philippines. JOURNAL OF FISH BIOLOGY 2020; 97:1247-1251. [PMID: 32671837 DOI: 10.1111/jfb.14464] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/01/2020] [Accepted: 07/11/2020] [Indexed: 06/11/2023]
Abstract
Cleaning interactions are essential for healthy marine ecosystem communities. This study reports the first documentation of the whale shark Rhincodon typus cleaning behaviour in the Indo-West Pacific by two wrasse species, the blue-streak cleaner wrasse Labroides dimidiatus and the moon wrasse Thalassoma lunare in Cebu, Philippines. This study documented 36 cleaning interactions with 14 individual whale sharks. The cleaning interactions appear opportunistic rather than targeted by the sharks, unlike that observed in other species of elasmobranchs. Further work should focus on understanding the drivers of these unique cleaning interactions.
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Affiliation(s)
- Gonzalo Araujo
- Large Marine Vertebrates Research Institute Philippines, Jagna, Philippines
| | - Joni A Miranda
- Large Marine Vertebrates Research Institute Philippines, Jagna, Philippines
| | - Harriet L Allen
- Large Marine Vertebrates Research Institute Philippines, Jagna, Philippines
| | - Jessica Labaja
- Large Marine Vertebrates Research Institute Philippines, Jagna, Philippines
| | - Sally Snow
- Large Marine Vertebrates Research Institute Philippines, Jagna, Philippines
| | - Alessandro Ponzo
- Large Marine Vertebrates Research Institute Philippines, Jagna, Philippines
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