Long-distance migration: evolution and determinants. Oikos 2, — Almpanidou, V. Thermal heterogeneity along the migration corridors of sea turtles: implications for climate change ecology. Marine Biol. Berger, J. Connecting the dots: an invariant migration corridor links the Holocene to the present. Block, B.
Tracking apex marine predator movements in a dynamic ocean. Nature , 86— Breed, G. Sex-specific, seasonal foraging tactics of adult grey seals Halichoerus grypus revealed bystate-space analysis. Ecology 90, — Casale, P. Sea turtle strandings reveal high anthropogenic mortality in Italian waters. CLS Google Scholar. Costello, M.
A census of marine biodiversity knowledge, resources, and future challenges. PLoS One 5:e Dingle, H. Oxford: Oxford University Press. Donlan, C. Using expert opinion surveys to rank threats to endangered species: a case study with sea turtles. Endres, C. Multi-modal homing in sea turtles: modeling dual use of geomagnetic and chemical cues in island-finding. ESRI Foley, A. Postnesting migratory behavior of loggerhead sea turtles Caretta caretta from three Florida rookeries.
Species Res. Girard, C. Post-nesting migrations of loggerhead sea turtles in the Gulf of Mexico: dispersal in highly dynamic conditions. Hart, K. Marine threats overlap key foraging habitat for two imperiled sea turtle species in the Gulf of Mexico.
Sympatry or syntopy? Investigating drivers of distribution and co-occurrence for two imperiled sea turtle species in Gulf of Mexico neritic waters. Common coastal foraging areas for loggerheads in the Gulf of Mexico: opportunities for marine conservation. Migration, foraging, and residency patterns for northern gulf loggerheads: implications of local threats and international movements.
PLoS One 9:e Movements and habitat-use of loggerhead sea turtles in the northern Gulf of Mexico during the reproductive period. PLoS One 8:e Biotelemetry 3, 1— Hays, G. Satellite telemetry suggests high levels of fishing-induced mortality in marine turtles. Global patterns for upper ceilings on migration distance in sea turtles and comparisons with fish, birds and mammals. Henkel, J. Oil spill: can local disturbance affect distant ecosystems through migratory shorebirds?
Bioscience 62, — Henkel, S. Shields and A. Payne Dordrecht: Springer , 93— Howard, E. The fall migration flyways of monarch butterflies in eastern North America revealed by citizen scientists. Insect Conserv. Jenni-Eiermann, S. Fuel supply and metabolic constraints in migrating birds.
B Biochem. Jones, F. Cumulative effects assessment: theoretical underpinnings and big problems. Jonsen, I. State space models for bio-loggers: a methodological road map.
Deep Sea Res. Meta-analysis of animal movement using state-space models. Ecology 84, — Identifying leatherback turtle foraging behaviour from satellite telemetry using a switching state-space model.
Keller, J. III, eds J. Wyneken, K. Lohmann, and J. LaBrecque, E. Biologically important areas for cetaceans within U. Lewison, R. Putting longline bycatch of sea turtles into perspective. Luschi, P. A review of long-distance movements by marine turtles, and the possible role of ocean currents. Oikos , — Sea Turtle Research Techniques Manual. Patterson, T. State-space models of individual animal movement. Trends Ecol. Pedler, R. Extreme nomadism in desert waterbirds: flights of the banded stilt.
Pendoley, K. Protected species use of a coastal marine migratory corridor connecting marine protected areas. R Core Team Sasso, C. Seasonal sea turtle mortality risk from forced submergence in bottom trawls. Schuyler, Q. Risk analysis reveals global hotspots for marine debris ingestion by sea turtles. Shaver, D. Soldevilla, M. Southwood, A. Physiological, behavioral, and ecological aspects of migration in reptiles. Steiniger, S. Free and open source geographic information tools for landscape ecology.
A scaled line-based kernel density estimator for the retrieval of utilization distributions and home ranges from GPS movement tracks. A risk-based approach to cumulative effect assessments for marine management.
Total Environ. Vander Zanden, H. Many people believe that while laying her eggs a sea turtles goes into a trance from which she can not be disturbed. This is not entirely true. A sea turtle is least likely to abandon nesting when she is laying her eggs, but some turtles will abort the process if they are harassed or feel they are in danger.
For this reason, it is important that sea turtles are never disturbed during nesting. Once all the eggs are in the chamber, the mother turtle uses her rear flippers to push sand over the top of the egg cavity. Gradually, she packs the sand down over the top and then begins using her front flippers to refill the body pit and disguise the nest. By throwing sand in all directions, it is much harder for predators to find the eggs.
After the nest is thoroughly concealed, the female crawls back to the sea to rest before nesting again later that season or before beginning her migration back to her feeding ground.
Once a female has left her nest, she never returns to tend it. Incubation takes about 60 days, but since the temperature of the sand governs the speed at which the embryos develop, the hatching period can cover a broad range.
Essentially, the hotter the sand surrounding the nest, the faster the embryos will develop. Cooler sand has a tendency to produce more males, with warmer sand producing a higher ratio of females.
Unlike baby alligators, which are liberated from their nest by their mother, sea turtle hatchlings must do it all themselves. Digging out of the nest is a group effort that can take several days. Hatchlings usually emerge from their nest at night or during a rainstorm when temperatures are cooler.
Once they decide to burst out, they erupt from the nest cavity as a group. The little turtles orient themselves to the brightest horizon, and then dash toward the sea. Once in the water, they typically swim several miles off shore, where they are caught in currents and seaweed that may carry them for years before returning to nearshore waters.
There are many obstacles for hatchlings in the open ocean. Sharks, big fish and circling birds all eat baby turtles, and they die after accidentally eating tar balls and plastic garbage. The obstacles are so numerous for baby turtles that only about one in 1, survives to adulthood. The ability of a sea turtle to migrate hundreds and occasionally thousands of miles from its feeding ground to its nesting beach is one of the most remarkable acts in the animal kingdom. That adult females return faithfully to nest on the very beach where they were born makes the feat even more amazing.
Research into where and how sea turtles migrate has been a focus of scientists for decades. The information collected is vital to the development of conservation strategies for the species. We now know that sea turtles undergo migration throughout their lives, beginning with the first frenzied swim as a hatchling. During its first critical 48 hours, a hatchling must travel from the beach to a place in the ocean where it is relatively safe from predators and where it can find food.
Many hatchlings in the Atlantic and Caribbean make their way into Gulf stream currents, which are filled with floating sargassum weed. There the young turtles find an ample food supply and few predators. After several years of floating around the Atlantic, these young turtles are big enough to venture back into nearshore waters.
In the diagram at left, the red lines indicate some possible migratory paths that different individuals may take. In addition, whereas most turtles appear to circle the gyre only once, some individuals may make more than one circuit, others may spend time in the Sargasso Sea, and a few have been captured in the Mediterranean.
Sea turtles typically spend their juvenile years eating and growing in nearshore habitats. Once they reach adulthood and sexual maturity, it is believed that they migrate to a new feeding ground.
It is in this primary feeding area where adult turtles probably remain throughout their lives, except during breeding season. When it is their time to mate and nest, both males and females leave their feeding grounds and migrate to the nesting beach. This periodic migration will continue throughout their lives. In the open ocean, sea turtles encounter strong currents; they have only modest vision, they can only raise their heads several inches out of the water, and there are often no visible landmarks.
Even with these limitations, sea turtles regularly navigate long distances to find the same tiny stretch of nesting beach. How they do it is one of the greatest mysteries in the animal kingdom, and finding an answer has been the focus of generations of researchers.
Loggerheads migration happens over different stages; they tend to spend more time traveling the currents. Hawsksbills tend to head towards coastal reefs. Except Leatherbacks, they prefer the open ocean. Once these turtles get bigger they will sometimes do daily migrations. During the day they will head toward shallower waters to feed, and then at night head to deeper waters to find shelter to rest.
Some sea turtles are seasonal travelers. They like to find their food up north during summer months. These same turtles will then travel south for the winter where the water is much warmer.
Once the females become adults, every few years they will then migrate to the beach they were born, this is called their natal beach.
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