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Black Sea Turtle ( Chelonia mydas agassizii) Life History in the Sanctuary of Colola Beach, Michoacan, Mexico. Animals (Basel) 2023; 13:ani13030406. [PMID: 36766296 PMCID: PMC9913439 DOI: 10.3390/ani13030406] [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: 11/15/2022] [Revised: 01/18/2023] [Accepted: 01/22/2023] [Indexed: 01/27/2023] Open
Abstract
Sea turtles present strategies that have allowed them to survive and reproduce. They spend most of their lives in the sea, except when they emerge as hatchlings from the nest and when the adult females return to nest. Those moments of their life cycle are vital for their reproductive success, conservation, and knowledge of their biology. This study reports the life history traits exhibited by female black sea turtles from Colola Beach, Mexico using morphometric and reproductive data obtained during 15 sampling seasons (1985-2000, n = 1500). The results indicate that nesting females have a mean body size of 85.7 cm and reach sexual maturity at 24 years old at a minimum size of 68 cm. Females deposit a mean of 69.3 eggs per clutch, and the mean fecundity was 196.4 eggs per female per season. The remigration intervals of 3 and 5 years were the most frequent registered. The life history traits found in the black sea turtle population present the lowest values reported with respect to studies conducted in the Atlantic and Indo-Pacific green turtle populations, which supports the hypothesis that this population is recovering, since morphometric and reproductive data represent young nesting turtles.
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Yao YT, Du Y, Pan JX, Lin CX, Ji X, You WH. Incubating green turtle (Chelonia mydas) eggs at constant temperatures: Hatching success, hatchling morphology and post-hatch growth. J Therm Biol 2022; 104:103182. [DOI: 10.1016/j.jtherbio.2021.103182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/18/2021] [Accepted: 12/31/2021] [Indexed: 10/19/2022]
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Morphometrics and blood analytes of leatherback sea turtle hatchlings (Dermochelys coriacea) from Florida: reference intervals, temporal trends with clutch deposition date, and body size correlations. J Comp Physiol B 2022; 192:313-324. [PMID: 34997274 DOI: 10.1007/s00360-021-01422-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/12/2021] [Accepted: 11/22/2021] [Indexed: 10/19/2022]
Abstract
The northwest Atlantic leatherback sea turtle (Dermochelys coriacea) population is exhibiting decreasing trends along numerous nesting beaches. Since population health and viability are inherently linked, it is important to establish species- and life-stage class-specific blood analyte reference intervals (RIs) so that effects of future disturbances on organismal health can be better understood. For hatchling leatherbacks, the objectives of this study were to (1) establish RIs for morphometrics and blood analytes; (2) evaluate correlations between hatchling morphometrics, blood analytes, and hatching success; and (3) determine temporal trends in hatchling morphometrics and blood analytes across nesting season. Blood samples were collected from 176 naturally emerging leatherback hatchlings from 18 clutches. Reference intervals were established for morphometrics and blood analytes. Negative relationships were noted between hatchling mass and packed cell volume, total white blood cells, heterophils, lymphocytes, and total protein and between body condition index (BCI) and immature red blood cells (RBC), RBC polychromasia and anisocytosis, and total protein. Clutch deposition date showed positive relationships with lymphocytes and total protein, and negative relationships with hatchling mass and BCI. Hatching success was positively correlated with mass, and negatively with total protein and glucose, suggesting that nutritional provisions in eggs, incubation time, and/or metabolic rates could change later in the season and affect survivorship. These various observed correlations provide evidence for increased physiological stress (e.g., inflammation, subclinical dehydration) in hatchlings emerging later in nesting season, presumably due to increased nest temperatures or other environmental factors (e.g., moisture/rainfall). Data reported herein provide morphometric and blood analyte data for leatherback hatchlings and will allow for future investigations into spatiotemporal trends and responses to various stressors.
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Matthews BL, Gatto CR, Reina RD. Effects of moisture during incubation on green sea turtle (Chelonia mydas) development, morphology and performance. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
While the effect of temperature on embryonic development in sea turtles has been well studied over recent years, our understanding of the effect of substrate moisture, another important environmental variable, is limited. High sand moisture decreases nest temperature through evaporative and direct cooling during rainfall, but its direct effect on hatchling development, morphology and performance is unclear. To address this knowledge gap, we incubated 40 green sea turtle Chelonia mydas clutches in a beach hatchery under either high (~8% v/v) or low (~5% v/v) sand moisture concentrations for the duration of embryonic development. In half of the clutches, temperature sensors were deployed to measure any effect of sand moisture on nest temperature. As hatchlings emerged, we measured body size and locomotory performance during the first 24 h, an important period of frenzied activity for sea turtles. We excavated clutches post-emergence to determine hatching success, emergence success and to determine the stage of embryonic death for unsuccessful eggs. High moisture concentrations increased incubation duration, decreased nest temperature and had marginal effects on hatchling morphology, but no effect on hatching success, stage of embryonic death, crawling speed or initial swimming performance. However, after 24 h of swimming, hatchlings from high-moisture clutches produced less mean swim thrust and spent less time powerstroking than hatchlings from low-moisture clutches, suggesting reduced swimming endurance and potentially impacting the ability of hatchlings to successfully disperse. The effect of moisture on nest temperature and hatchling endurance highlights the importance of considering rainfall patterns when predicting future impacts of climate change on sea turtle populations.
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Affiliation(s)
- BL Matthews
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - CR Gatto
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - RD Reina
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
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Kang CQ, Meng QY, Dang W, Lu HL. Divergent incubation temperature effects on thermal sensitivity of hatchling performance in two different latitudinal populations of an invasive turtle. J Therm Biol 2021; 100:103079. [PMID: 34503815 DOI: 10.1016/j.jtherbio.2021.103079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/05/2021] [Accepted: 08/12/2021] [Indexed: 11/19/2022]
Abstract
The incubation temperature for embryonic development affects several aspects of hatchling performance, but its impact on the thermal sensitivity of performance attributes remains poorly investigated. In the present study, Trachemys scripta elegans hatchlings from two different latitudinal populations were collected to assess the effects of different incubation temperatures on the locomotor (swimming speed) and physiological (heart rate) performances, and the thermal sensitivity of these two attributes. The incubation temperature significantly affected the examined physiological traits. Hatchling turtles produced at low incubation temperature exhibited relatively higher cold tolerance (lower body temperatures at which the animals lose the ability to escape from the lethal conditions), and reduced heart rate and swimming speed. Furthermore, the effect of incubation temperature on the thermal sensitivity of swimming speed differed between the low- and high-latitude populations. At relatively high incubation temperatures, the high-latitude hatchling turtles exhibited reduced thermal sensitivities of swimming speed than those of the low-latitude ones. Reduced thermal sensitivity of locomotor performance together with high cold tolerance, exhibited by the high-latitude hatchling turtles potentially reflected local adaptation to relatively colder and more thermally-variable environments.
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Affiliation(s)
- Chun-Quan Kang
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Qin-Yuan Meng
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Wei Dang
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Hong-Liang Lu
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China.
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Jonsson B, Jonsson N. Differences in growth between offspring of anadromous and freshwater brown trout Salmo trutta. JOURNAL OF FISH BIOLOGY 2021; 99:18-24. [PMID: 33534141 DOI: 10.1111/jfb.14693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 01/19/2021] [Accepted: 01/02/2021] [Indexed: 06/12/2023]
Abstract
In this study, individual growth of juvenile offspring of anadromous and freshwater resident brown trout Salmo trutta and crosses between the two from the River Imsa, Norway, was estimated. The juveniles were incubated until hatching at two temperatures (±S.D.), either 4.4 ± 1.5°C or 7.1 ± 0.6°C. Growth rate was estimated for 22 days in August-September when the fish on average were c. 8 g in wet mass, and the estimates were standardized to 1 g fish dry mass. Offspring of anadromous S. trutta grew better at both 15 and 18°C than offspring of freshwater resident S. trutta or offspring of crosses between the two S. trutta types. This difference appears not to result from a maternal effect because anadromous S. trutta grew better than the hybrids with anadromous mothers. Instead, this appears to be an inherited difference between the anadromous and the freshwater resident fish lending support to the hypothesis that anadromous and freshwater resident S. trutta in this river differ in genetic expression. Egg incubation temperature of S. trutta appeared not to influence the later growth as reported earlier from the studies of Atlantic salmon Salmo salar.
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Affiliation(s)
- Bror Jonsson
- Norwegian Institute for Nature Research, Oslo, Norway
| | - Nina Jonsson
- Norwegian Institute for Nature Research, Oslo, Norway
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Maurer AS, Seminoff JA, Layman CA, Stapleton SP, Godfrey MH, Reiskind MOB. Population Viability of Sea Turtles in the Context of Global Warming. Bioscience 2021. [DOI: 10.1093/biosci/biab028] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Sea turtles present a model for the potential impacts of climate change on imperiled species, with projected warming generating concern about their persistence. Various sea turtle life-history traits are affected by temperature; most strikingly, warmer egg incubation temperatures cause female-biased sex ratios and higher embryo mortality. Predictions of sea turtle resilience to climate change are often focused on how resulting male limitation or reduced offspring production may affect populations. In the present article, by reviewing research on sea turtles, we provide an overview of how temperature impacts on incubating eggs may cascade through life history to ultimately affect population viability. We explore how sex-specific patterns in survival and breeding periodicity determine the differences among offspring, adult, and operational sex ratios. We then discuss the implications of skewed sex ratios for male-limited reproduction, consider the negative correlation between sex ratio skew and genetic diversity, and examine consequences for adaptive potential. Our synthesis underscores the importance of considering the effects of climate throughout the life history of any species. Lethal effects (e.g., embryo mortality) are relatively direct impacts, but sublethal effects at immature life-history stages may not alter population growth rates until cohorts reach reproductive maturity. This leaves a lag during which some species transition through several stages subject to distinct biological circumstances and climate impacts. These perspectives will help managers conceptualize the drivers of emergent population dynamics and identify existing knowledge gaps under different scenarios of predicted environmental change.
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Affiliation(s)
- Andrew S Maurer
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, in the United States; he is also a research associate with the Jumby Bay Hawksbill Project in Antigua, West Indies
| | - Jeffrey A Seminoff
- Marine Turtle Ecology and Assessment Program, National Oceanic and Atmospheric Administration's Southwest Fisheries Science Center, La Jolla, California, United States
| | - Craig A Layman
- Center for Energy, Environment, and Sustainability, Wake Forest University, in Winston-Salem, North Carolina, in the United States
| | - Seth P Stapleton
- Conservation and animal health sciences, Minnesota Zoo, Apple Valley, Minnesota; he is also an adjunct faculty member in the Department of Fisheries, Wildlife, and Conservation Biology, University of Minnesota, in Minneapolis, Minnesota, in the United States
| | - Matthew H Godfrey
- North Carolina Wildlife Resources Commission, Raleigh, North Carolina, United States
| | - Martha O Burford Reiskind
- Martha Burford Reiskind is an assistant professor in the Department of Biological Sciences and the director of the Genetics and Genomics Scholars program, North Carolina State University, Raleigh, North Carolina, United States
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Kobayashi S, Endo D, Kondo S, Kitayama C, Ogawa R, Arai K, Watanabe G, Kawaguchi M. Investigating the effects of nest shading on the green turtle (Chelonia mydas) hatchling phenotype in the Ogasawara islands using a field-based split clutch experiment. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:629-636. [PMID: 32894008 DOI: 10.1002/jez.2411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 12/27/2022]
Abstract
The Ogasawara Islands are an important rookery for the green turtle (Chelonia mydas) in the North Pacific. Green turtles possess temperature-dependent sex determination, and warmer incubation temperatures produce more females than males. Therefore, conservation practices such as nest shading may be required for this population to mitigate the effect of global warming on their sex ratio. To consider the application of such conservation practices in the Ogasawara population, it is fundamental to understand how artificially modified nest environments will affect green turtle hatchling phenotypes that influence their fitness. Here, we investigated the effects of nest shading on green turtle hatchling phenotypes in the Ogasawara population by using a split clutch experiment equally separating the clutch, relocating each half-clutch into an outdoor hatchery area either with or without shading, and observing the subsequent hatchling phenotype. Our results showed that the shading treatment produced hatchlings with a better self-righting response and a larger carapace size. Additionally, the shading treatment mostly reduced the production of hatchlings with a nonmodal scute pattern and produced hatchlings with a smaller unabsorbed yolk sac, which may be associated with their residual yolk mass. These results suggest that conservation practices such as shading could alter not only the sex ratio but also the hatchling phenotype that influences their fitness. Hence, our results suggest that applications of such conservation strategies must be carefully considered.
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Affiliation(s)
- Shohei Kobayashi
- Organization for the Strategic Coordination of Research and Intellectual Property, Meiji University, Kanagawa, Japan
| | - Daisuke Endo
- Course of Applied Marine Biosciences, Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Tokyo, Japan
| | - Satomi Kondo
- Everlasting Nature of Asia, Ogasawara Marine Center, Tokyo, Japan
| | - Chiyo Kitayama
- Everlasting Nature of Asia, Ogasawara Marine Center, Tokyo, Japan
| | - Ryuta Ogawa
- Everlasting Nature of Asia, Ogasawara Marine Center, Tokyo, Japan
| | - Katsuhiko Arai
- Department of Biological Production Science, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Gen Watanabe
- Laboratory of Veterinary Physiology, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Maiko Kawaguchi
- Laboratory of Animal Behavior and Environmental Science, Department of Agriculture, School of Agriculture, Meiji University, Kanagawa, Japan
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Lamont MM, Johnson D, Carthy RR. The incubation environment of nests deposited by a genetically distinct group of loggerhead sea turtles in Northwest Florida. Glob Ecol Conserv 2020. [DOI: 10.1016/j.gecco.2020.e01070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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