Identification of likely foraging habitat of pelagic loggerhead sea turtles (Caretta caretta) in the North Atlantic through analysis of telemetry track sinuosity

Discerning the foraging habitat requirements of wildlife is key to providing for their conservation and management, especially with rare species. Sea turtles are slow-growing, late-maturing species that undertake wide-ranging migrations, making them especially susceptible to changes and disruptions in their environment. To protect and successfully manage these imperiled populations, an understanding of their spatial ecology is required; thus, characterizing critical habitats, identifying high-density areas, and identifying foraging regions is essential. We captured 30 loggerhead sea turtles Caretta caretta (male and female; juvenile and adult) in the estuarine waters of North Carolina (USA) and tracked them in western North Atlantic neritic (nearshore and offshore) waters. Using a combination of satellite telemetry and spatial modeling techniques, we characterized their movements and identified foraging and overwintering sites. Average core-use areas in the north had greater net primary production (NPP) and were smaller than those in the south, indicating more abundant marine resources in northern foraging regions. In summer, loggerheads migrated to both northern and southern foraging grounds, but most (53%) resided within North Carolina neritic waters. Likewise, the majority of loggerheads (67%) we tracked in winter remained in North Carolina neritic waters, underscoring the importance of this area as year-round foraging habitat, and lending to its consideration as potential critical habitat for both juvenile and adult loggerheads. The change to foraging behavior mode was significantly influenced by day of the year, geographic location, and NPP; however, individual-specific factors influenced switching probabilities relative to other covariates. Data highlighting ‘hotspots’ or densely used areas by foraging sea turtles can thus be used by conservation managers to make informed decisions concerning sea turtle conservation measures.

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Estimating the age of juvenile loggerhead sea turtles in the North Atlantic

Canadian Journal of Zoology ◽

10.1139/z97-005 ◽

1997 ◽

Vol 75 (1) ◽

pp. 40-46 ◽

Cited By ~ 58

Author(s):

G. C. Hays ◽

R. Marsh

Keyword(s):

North Atlantic ◽

Sea Turtles ◽

Drift Time ◽

Loggerhead Sea Turtles ◽

The North ◽

The United Kingdom ◽

The North Atlantic ◽

Area North ◽

Using Data ◽

Nesting Beaches

Analysis of previously published records shows that the modal size of juvenile loggerhead sea turtles (Caretta caretta) found around the United Kingdom (the area north of 49°N and east of 12°W) is a carapace length of 20.5 cm. These turtles are believed to originate from nesting beaches in North America (principally Florida). We estimated their trans-Atlantic drift time using data from satellite-tracked buoys and from a mathematical model and, hence, estimated that the modal age of these juvenile turtles was between 1.80 and 3.75 years.

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Genetic stock composition of loggerhead turtles Caretta caretta bycaught in the pelagic waters of the North Atlantic

Endangered Species Research ◽

10.3354/esr00535 ◽

2013 ◽

Vol 22 (1) ◽

pp. 73-84 ◽

Cited By ~ 11

Author(s):

EL LaCasella ◽

SP Epperly ◽

MP Jensen ◽

L Stokes ◽

PH Dutton

Keyword(s):

North Atlantic ◽

Caretta Caretta ◽

Genetic Stock ◽

The North ◽

Loggerhead Turtles ◽

The North Atlantic

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Orientation behaviour of leatherback sea turtles within the North Atlantic subtropical gyre

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.3129 ◽

2015 ◽

Vol 282 (1804) ◽

pp. 20143129 ◽

Cited By ~ 4

Author(s):

Kara L. Dodge ◽

Benjamin Galuardi ◽

Molly E. Lutcavage

Keyword(s):

North Atlantic ◽

Sea Turtles ◽

Sensory Information ◽

Subtropical Gyre ◽

Dermochelys Coriacea ◽

Male Adult ◽

The North ◽

The North Atlantic ◽

Leatherback Sea Turtles ◽

Nesting Beaches

Leatherback sea turtles ( Dermochelys coriacea ) travel thousands of kilometres between temperate feeding and tropical breeding/over-wintering grounds, with adult turtles able to pinpoint specific nesting beaches after multi-year absences. Their extensive migrations often occur in oceanic habitat where limited known sensory information is available to aid in orientation. Here, we examined the migratory orientation of adult male, adult female and subadult leatherbacks during their open-ocean movements within the North Atlantic subtropical gyre by analysing satellite-derived tracks from fifteen individuals over a 2-year period. To determine the turtles' true headings, we corrected the reconstructed tracks for current drift and found negligible differences between current-corrected and observed tracks within the gyre. Individual leatherback headings were remarkably consistent throughout the subtropical gyre, with turtles significantly oriented to the south-southeast. Adult leatherbacks of both sexes maintained similar mean headings and showed greater orientation precision overall. The consistent headings maintained by adult and subadult leatherbacks within the gyre suggest use of a common compass sense.

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First satellite tracks of neonate sea turtles redefine the ‘lost years’ oceanic niche

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.3039 ◽

2014 ◽

Vol 281 (1781) ◽

pp. 20133039 ◽

Cited By ~ 88

Author(s):

Katherine L. Mansfield ◽

Jeanette Wyneken ◽

Warren P. Porter ◽

Jiangang Luo

Keyword(s):

North Atlantic ◽

Sea Turtles ◽

Life Stage ◽

Sea Turtle ◽

Sea Surface ◽

The North ◽

Satellite Transmitters ◽

The North Atlantic ◽

Solar Powered

Few at-sea behavioural data exist for oceanic-stage neonate sea turtles, a life-stage commonly referred to as the sea turtle ‘lost years’. Historically, the long-term tracking of small, fast-growing organisms in the open ocean was logistically or technologically impossible. Here, we provide the first long-term satellite tracks of neonate sea turtles. Loggerheads ( Caretta caretta ) were remotely tracked in the Atlantic Ocean using small solar-powered satellite transmitters. We show that oceanic-stage turtles (i) rarely travel in Continental Shelf waters, (ii) frequently depart the currents associated with the North Atlantic Subtropical Gyre, (iii) travel quickly when in Gyre currents, and (iv) select sea surface habitats that are likely to provide a thermal benefit or refuge to young sea turtles, supporting growth, foraging and survival. Our satellite tracks help define Atlantic loggerhead nursery grounds and early loggerhead habitat use, allowing us to re-examine sea turtle ‘lost years’ paradigms.

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Migration, distribution, and diving behavior of adult male loggerhead sea turtles (Caretta caretta) following dispersal from a major breeding aggregation in the Western North Atlantic

Marine Biology ◽

10.1007/s00227-011-1826-0 ◽

2011 ◽

Vol 159 (1) ◽

pp. 113-125 ◽

Cited By ~ 48

Author(s):

Michael D. Arendt ◽

Albert L. Segars ◽

Julia I. Byrd ◽

Jessica Boynton ◽

Jeffrey A. Schwenter ◽

...

Keyword(s):

Adult Male ◽

North Atlantic ◽

Sea Turtles ◽

Caretta Caretta ◽

Diving Behavior ◽

Loggerhead Sea Turtles

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Helminth Infection of the Loggerhead Sea Turtle Caretta caretta along the Coasts of Sicily and the North West Adriatic Sea

Animals ◽

10.3390/ani11051408 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1408

Author(s):

Antonino Gentile ◽

Tullia Amato ◽

Andrea Gustinelli ◽

Maria Letizia Fioravanti ◽

Delia Gambino ◽

...

Keyword(s):

Adriatic Sea ◽

Sea Turtles ◽

Single Species ◽

Caretta Caretta ◽

Sea Turtle ◽

Helminth Parasites ◽

Loggerhead Sea Turtles ◽

Loggerhead Sea Turtle ◽

North West ◽

The North

We provide new data on the presence of helminth parasites in 64 individual loggerhead sea turtles Caretta caretta stranded along the coasts of Sicily and the northwest Adriatic Sea between June 2014 and August 2016. The necropsy examination revealed 31 individuals (48.4%) positive for endoparasites, showing a greater prevalence of trematodes than nematodes. In particular, seven species and a single genus of Trematoda (Hapalotrema) and a single species and genus of Nematoda (Kathlania) were identified. Among the Digenea flukes the species with the highest prevalence of infection were Rhytidodes gelatinosus (34.6%) and Hapalotrema sp. (33.3%), while among the Nematoda they were Kathlania sp. (33.3%) and Sulcascaris sulcata (33.3%). Analysis of variance (ANOVA) was applied among the recovery sites of the stranded loggerhead sea turtles and prevalence of endoparasites was used to highlight any relationship between the parasites and the origin of the hosts. ANOVA showed significant differences (p < 0.001) among the data used.

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Record of the Loggerhead Sea Turtle, Caretta caretta (Testudines, Cheloniidae), in the Black Sea with the Review of the Species Occurrence in the Region

Zoodiversity ◽

10.15407/zoo2021.02.127 ◽

2021 ◽

Vol 55 (2) ◽

pp. 127-132

Author(s):

O. Zinenko ◽

K. A. Vishnyakova ◽

L. Stoyanov ◽

P. E. Gol’din

Keyword(s):

Black Sea ◽

Sea Turtles ◽

Caretta Caretta ◽

First Record ◽

Sea Turtle ◽

The Black Sea ◽

Loggerhead Sea Turtles ◽

Loggerhead Sea Turtle ◽

The North ◽

North Western

A rare live record of the loggerhead sea turtle Caretta caretta (Linnaeus, 1758) is reported from the Dzharylgach Gulf in the north-western Black Sea. This is the first record from Ukrainian waters since 1962 and the northernmost record of the species in the Black Sea. The loggerhead sea turtles of the east Mediterranean origin are increasingly often seen in the Marmara and the Black Sea during the latest decade, which is an evidence for potential expansion of this species range, at least partly due to climate changes. Key words: sea turtles, Caretta caretta, Black Sea, Ukraine, range expansion.

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Lagrangian modeling of the active dispersal of juvenile leatherback turtles in the North Atlantic Ocean

10.5194/egusphere-egu2020-17793 ◽

2020 ◽

Author(s):

Philippe Gaspar ◽

Maxime Lalire ◽

Pierrick Giffard ◽

Tony Candela

Keyword(s):

North Atlantic ◽

Sea Turtles ◽

Sea Turtle ◽

Juvenile Stage ◽

Subtropical Gyre ◽

Ocean Currents ◽

Leatherback Turtles ◽

The North ◽

Active Dispersal ◽

The North Atlantic

It has long been assumed that young sea turtles drift passively with ocean currents. As a consequence, simple Lagrangian models have often been used to investigate the dispersal of various sea turtle populations during their juvenile stage. However, evidence is growing that juvenile sea turtles do not drift purely passively with ocean currents but also display some swimming activity, generally directed towards favorable habitats.We have thus developed a new Sea Turtle Active Movement Model (STAMM) in which simulated individuals disperse under the combined influence of oceanic currents and swimming movements triggered by the need to find suitable habitats, that is areas with suitable water temperatures and sufficient food.&#160; Preferred temperatures and food requirements are modeled to vary with the age (or size) of the simulated individuals.STAMM is used here to investigate the active dispersal of juvenile leatherback turtles (Dermochelys coriacea) born in French Guiana, a major rookery for the Northwest Atlantic population. Our simulations reveal that:<ol><li>&#160;While currents broadly shape the dispersal area, habitat-driven movements profoundly structure the spatio-temporal distribution of juveniles within this area. Passive turtles can drift far North in deadly cold waters or concentrate in oligotrophic waters found at the center of the North Atlantic subtropical gyre. On the contrary, actively swimming juveniles tend to concentrate in favorable habitats along the northern boundary of the subtropical gyre and undertake seasonal north-south migrations allowing them to remain in suitable water temperatures.</li> <li>Active juveniles ultimately target rich areas of the Eastern Atlantic basin, in particular in the Bay of Biscay, off Galicia, Portugal and Mauritania, and in the western Mediterranean Sea where juvenile leatherbacks are actually observed. These zones are inaccessible to passive turtles.</li> <li>Arrival times of the active juveniles in these favorable zones are consistent with the observed sizes of individuals bycaught or stranded in these areas;</li> </ol>All together these results suggest that active habitat-driven swimming movements shall be systematically taken into account to produce realistic simulations of the spatial distribution of sea turtles during their pelagic juvenile stage. This is much needed to help develop effective conservation measures targeting this critical life stage.

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