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Leatherback logging in the Atlantic

By JW Dowey - 27 Mar 2014 10:10:0 GMT
Leatherback logging in the Atlantic

In the winter, leatherbacks leave the colder waters and migrate to the Caribbean, where the larger animals are easily seen in the breeding areas, near hopefully-protected beaches. This individual is coming up for air near Curacao; Leatherback image; Credit: © Shutterstock

It seems leatherback turtles drive on the left. The west side off the Atlantic Ocean has been found to be the predominant habitat for most animals investigated with highly-accurate GPS-linked STDRs. The tags used were very user-friendly with hydrodynamic attachment, made by Wildlife Computers. Previous studies have found dive duration and speed affected negatively by harnesses and directly attached tags.

The NE US continental shelf seemed attractive to the turtles before they dispersed throughout the NW Atlantic. Few went north to the normally popular Canada shelf and none seemed to venture to the eastern half of the ocean. Canadian turtles who were in an older age-bracket, did come south however. As migrating distance depends on size and stored body fat, sub-adults could well have been near the northern limit of their range. Relevant studies on cod and bluefin tuna point to the same migratory limitation for sub-adult leatherbacks, which have been prove capable of penetrating further north than any other turtle. The larger leatherbacks do have their unique thermoregulation capability and insulation to help.

The annual migrations tend to be north in the summer and south towards the tropics in the winter. Sunfish, basking sharks, tuna and swordfish have similar habitat change preferences. Prey and temperature govern those choices of course, with gelatinous zooplankton and the large (Scyphozoan) jellyfish heavily influencing Dermatochelys. We have some background stories on the intake of plastic waste by turtles, mistaking it for gelatinous prey in Marine turtle ingestion of plastic investigated .

Sub-adults, small adult males and single females between nesting years stay in the deep ocean in summer according to the satellite data. Large males and reproducing females remove to the romantic coastal breeding areas. Small males in particular will seek out the less common regions for foraging in the warm winter seas. The sub-adults don't travel as far south as the others, but all except possibly this group have specific goals they will remember from previous experience in places they find useful for breeding or forage.

The role of leatherbacks as predators in our ecosystems is underplayed, but with this satellite telemetry of just 20 individuals, we have insights into how they gather at shelves near North American and Caribbean coasts where we can discern surface chlorophyll (phytoplankton) and many physical characteristics of their habitat. Now we have to prevent human activity at these sites from causing further interference.

We have some background stories on the intake of plastic waste by turtles, mistaking it for gelatinous prey in Marine turtle ingestion of plastic investigated .

Kara L. Dodge, Benjamin Galuardi, Timothy J. Miller and Molly E. Lutcavage of the Universities of New Hampshire and Massachusetts and the National Marine Fisheries Service in Woods Hole present their paper as Leatherback Turtle Movements, Dive Behavior, and Habitat Characteristics in Ecoregions of the Northwest Atlantic Ocean a> in the open-access journal PloS One.