International Movements of Adult Female Hawksbill Turtles (Eretmochelys imbricata): First Results from the Caribbean's Marine Turtle Tagging Centre

Tag recoveries from four adult female hawksbill turtles, Eretmochelys imbricata, tagged on the Great Barrier Reef, Australia, are reported. Hawksbill turtles on breeding migrations move between Australia and neighbouring countries including Vanuatu, Solomon Islands, Papua New Guinea and Indonesia. Migratory distances between foraging areas and nesting beaches ranged from 368 to 2425 km. A review of data from tag recoveries, genetic analysis and satellite telemetry indicates that adult female hawksbill turtles often exhibit migratory behaviour parallelling that of other marine turtle species. This study refutes the myth that hawksbill turtles remain resident at reefs associated with their nesting beaches.

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Natal foraging philopatry in eastern Pacific hawksbill turtles

Royal Society Open Science ◽

10.1098/rsos.170153 ◽

2017 ◽

Vol 4 (8) ◽

pp. 170153 ◽

Cited By ~ 6

Author(s):

Alexander R. Gaos ◽

Rebecca L. Lewison ◽

Michael P. Jensen ◽

Michael J. Liles ◽

Ana Henriquez ◽

...

Keyword(s):

Genetic Research ◽

Eastern Pacific ◽

Marine Turtle ◽

Natal Philopatry ◽

Eretmochelys Imbricata ◽

Turtle Species ◽

Marine Turtles ◽

Complex Processes ◽

Natal Homing ◽

Hawksbill Turtles

The complex processes involved with animal migration have long been a subject of biological interest, and broad-scale movement patterns of many marine turtle populations still remain unresolved. While it is widely accepted that once marine turtles reach sexual maturity they home to natal areas for nesting or reproduction, the role of philopatry to natal areas during other life stages has received less scrutiny, despite widespread evidence across the taxa. Here we report on genetic research that indicates that juvenile hawksbill turtles ( Eretmochelys imbricata ) in the eastern Pacific Ocean use foraging grounds in the region of their natal beaches, a pattern we term natal foraging philopatry. Our findings confirm that traditional views of natal homing solely for reproduction are incomplete and that many marine turtle species exhibit philopatry to natal areas to forage. Our results have important implications for life-history research and conservation of marine turtles and may extend to other wide-ranging marine vertebrates that demonstrate natal philopatry.

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Signs of hope in the eastern Pacific: international collaboration reveals encouraging status for a severely depleted population of hawksbill turtles Eretmochelys imbricata

Oryx ◽

10.1017/s0030605310000773 ◽

2010 ◽

Vol 44 (4) ◽

pp. 595-601 ◽

Cited By ~ 25

Author(s):

Alexander R. Gaos ◽

F.A. Abreu-Grobois ◽

J. Alfaro-Shigueto ◽

D. Amorocho ◽

R. Arauz ◽

...

Keyword(s):

El Salvador ◽

Working Group ◽

Eastern Pacific ◽

Marine Turtle ◽

Current Status ◽

Eretmochelys Imbricata ◽

Conservation Projects ◽

Available Information ◽

Nesting Activity ◽

Hawksbill Turtles

AbstractWhile little is known about hawksbill turtles Eretmochelys imbricata in the eastern Pacific Ocean, available information suggests that the population has declined substantially in recent decades and could be near extirpation in the region. To evaluate the current status of the population more effectively and to determine the feasibility of recovery efforts, a workshop of regional marine turtle specialists was held in June 2008 in Los Cóbanos, El Salvador. An international working group, Iniciativa Carey del Pacífico Oriental (ICAPO; Eastern Pacific Hawksbill Initiative in English), was established to consolidate information, promote conservation projects and raise awareness about the species. We present information derived from the workshop and compiled by the ICAPO working group since that time. Considering only records from 1 January 2007 to 31 May 2009 it appears that El Salvador hosts the majority of known hawksbill turtle nesting activity in the eastern Pacific, with 79.6% (n = 430) of all nesting observation records, and Mexico hosts the majority of records of hawksbill turtles at sea, with 60.3% (n = 44) of all in-water observation records. Although current abundance is very low, the pervasiveness of the species in the region suggests potential for conservation and recovery. Despite a historical paucity of research focusing on this population, the relatively large and steadily increasing number of records as a result of concerted efforts demonstrates the viability of the ICAPO network as an instrument to promote conservation of this species in the eastern Pacific.

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Serum testosterone and estradiol-17ß levels during the peak period in a year-round Hawksbill Turtle Eretmochelys imbricata L. nesting population

Pacific Conservation Biology ◽

10.1071/pc070151 ◽

2007 ◽

Vol 13 (3) ◽

pp. 151 ◽

Cited By ~ 6

Author(s):

K. A. Dobbs ◽

J. D. Miller ◽

D. W. Owens ◽

A. M. Landry Jr.

Keyword(s):

Austral Summer ◽

Serum Testosterone ◽

Marine Turtle ◽

Gonadal Hormone ◽

Future Research ◽

Hormone Concentration ◽

Peak Period ◽

Eretmochelys Imbricata ◽

Hawksbill Turtles ◽

Nesting Season

Serum testosterone (T) and estradiol-17� (E2 ) concentrations were determined for 95 Hawksbill Turtles Eretmochelys imbricate nesting at Milman Island, northern Great Barrier Reef, Australia. This information describes gonadal hormone concentration during the Austral summer months for peak nesting in an E. imbricata population that nest year-round. A total of 173 samples was collected from 95 turtles, with 39 turtles sampled sequentially within their nesting cycle (n = 117 samples) and the remainder sampled at random. E2 -levels were measured from seven turtles sampled sequentially within their nesting cycle (n = 31 samples). T-Ievels ranged from 0 to 7 520 pg/ml; E2-Ieveis varied between 0.0 and 119.0 pg/ml. Peak T-Ievels in turtles sampled sequentially within their nesting cycle occurred after laying clutch number two or three while E2-levels peaked after clutch number one or two; levels of both hormones decreased thereafter. T- and E2-levels decreased monthly (December to March) within a nesting season. Based on T-Ievels, the greatest proportion (58%) of turtles began their nesting cycle in December. Turtles in the middle of their nesting cycle were found in equal proportions (27?35%) throughout the Austral summer months. Turtles at the end of their nesting cycle were most frequent (61%) in March. The implications of these results for future research and for managing access to islands with year-round marine turtle nesting are discussed.

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An assessment of the marine turtle fishery in Grenada, West Indies

Oryx ◽

10.1017/s0030605307000613 ◽

2007 ◽

Vol 41 (3) ◽

pp. 330-336 ◽

Cited By ~ 7

Author(s):

S. Grazette ◽

J.A. Horrocks ◽

Paul E. Phillip ◽

Crafton J. Isaac

Keyword(s):

Breeding Season ◽

Landing Site ◽

Chelonia Mydas ◽

Marine Turtle ◽

Catch Per Unit Effort ◽

Eretmochelys Imbricata ◽

Green Turtles ◽

Hawksbill Turtles ◽

Relative Scarcity ◽

Made In

AbstractThe marine turtle fishery of Grenada was assessed using interviews with marine turtle fishermen and by examination of turtle catch data from a major landing site. An estimated 782 turtles, mainly Endangered green turtles Chelonia mydas and Critically Endangered hawksbill turtles Eretmochelys imbricata, were caught around Grenada and its sister island Carriacou each year between 1996 and 2001 during an annual 8-month open season, with only a small percentage being officially recorded at a landing site. Turtles were primarily caught with nets and spearguns, with more green turtles caught by net fishermen and more hawksbill turtles by spear fishermen. Catch per unit effort data suggested that relative abundance had declined since the previous estimate was made in 1969. Few adult green or loggerhead turtles Caretta caretta were caught, indicating the relative scarcity of this size class of these two species around Grenada. Adult-sized hawksbill turtles were caught regularly, with larger adults being caught in the non-breeding months of the open season than in the breeding months. A higher percentage of adult hawksbill turtles present during the breeding season are likely to be animals that nest in Grenada, and their smaller size may result from historically heavy fishing pressure. The larger sized adults caught during the non-breeding season are likely to be animals that forage around Grenada but breed elsewhere in the Caribbean where they are protected.

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First record of the marine turtle leech (Ozobranchus margoi) on hawksbill turtles (Eretmochelys imbricata) in the inner granitic Seychelles

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v85i1.1604 ◽

2018 ◽

Vol 85 (1) ◽

Author(s):

Byron M. Göpper ◽

Nina M. Voogt ◽

Andre Ganswindt

Keyword(s):

Chelonia Mydas ◽

First Record ◽

The Other ◽

Marine Turtle ◽

Eretmochelys Imbricata ◽

History Museum ◽

Turtle Species ◽

Routine Monitoring ◽

Hawksbill Turtles ◽

Cousine Island

Ozobranchus spp. are leeches that feed solely on turtle blood. They are common ectoparasites found on a range of marine turtle species, with some species of the leech being implicated as vectors of fibropapilloma-associated turtle herpesvirus (FPTHV). Green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) turtles are the two commonly occurring species in the inner granitic islands of the Seychelles. Routine monitoring of nesting turtles on Cousine Island, Seychelles, allowed for opportunistic sightings of leeches on two hawksbill females. In both cases infestation was low, with three leeches collected off one female turtle and five off the other. No obvious signs of papillomas secondary to infection of FPTHV were seen. All of the turtle leeches collected were determined to be Ozobranchus margoi as they had five pairs of lateral digiform branchiae. The specimens were deposited in the Seychelles Natural History Museum on Mahé. To the best of our knowledge this is the first record of Ozobranchus margoi recorded in the inner granitic Seychelles on hawksbill turtles.

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