Featured Research

from universities, journals, and other organizations

Threatened Atlantic Leatherback Turtles Split Into Two Groups To Forage, Isotope Analysis Suggests

Date:
March 26, 2008
Source:
Public Library of Science
Summary:
The beaches of French Guiana constitute a major reproduction site for leatherback turtles. This sea turtle, although a protected species, is threatened by human activity. Female turtles return to the same beach every two to three years to lay their eggs; what happens in the interval remains a mystery. In a new study a group of French and Belgian scientists found that the turtles segregate into two distinct feeding units.

The beaches of French Guiana constitute a major reproduction site for leatherback turtles. This sea turtle, although a protected species, is threatened by human activity: it ingests plastics, get accidentally caught in fishing nets, sees its egg-laying sites destroyed and its adults hunted illegally for their meat and their eggs. Female turtles return to the same beach every two to three years to lay their eggs.

What happens in the interval remains a mystery. It is sometimes possible to spot them offshore in the North Atlantic. Some even swim to very high latitudes (Canada) in search of their favorite food (principally jellyfish). Argos beacons have recently revealed that some females were swimming in two principal directions: the north as would be expected, but also towards the African coast east of French Guiana.

The question is whether these locations represent two distinct feeding areas or simply an extra stopover in their migration to the far north.

Several French and Belgian scientists (University of Paris-Sud and the Laboratory for Oceanology of the University of Liège, respectively) have studied the question, in particular the carbon and nitrogen isotope ratios (d13C and d15N) in the blood and eggs of these turtles. Isotope ratios are indeed significant dietary markers and indicate, if conditions are favorable, the diet of the animals in recent days, weeks or months, depending on the tissue analyzed.

These analyses are the culmination of long and painstaking fieldwork carried out by the team from the University of Paris-Sud in Guiana. Researchers worked around the clock spotting the turtles, identifying them thanks to their tags (electronic chips serving to identify the animals), and taking blood and egg samples. Some of the sampled females had laid their eggs on the same beach two years previously, others three.

Analysis of the samples showed that the carbon and nitrogen isotrope ratios were different for each group, which suggests that the turtles had had a different diet before laying their eggs. These isotope ratios (especially the carbon ratios) are indicative of a dichotomy in the feeding areas of the two groups: one fed in the high latitudes of the North Atlantic's pelagic zone, the other in the low latitudes of the North Atlantic off the African and Iberian coasts.

The existence of these two distinct feeding areas remains to be confirmed over the long run (through the observation of sea turtles), but these preliminary results already show how urgent it is to determine the precise geographical feeding areas used by the leatherback turtles as well as the duration of their visit during the interval between egg-layings.

The fact that leatherback turtles use two distinct feeding areas over a long period has major implications as far as their preservation is concerned. If one of these two habitats were to be damaged because of overfishing, pollution, sea traffic, etc, this could have dramatic repercussions on the survival of the species.

Journal reference: Caut S, Guirlet E, Angulo E, Das K, Girondot M (2008) Isotope Analysis Reveals Foraging Area Dichotomy for Atlantic Leatherback Turtles. PLoS One 3(3): e1845. doi:10.1371/journal.pone.0001845


Story Source:

The above story is based on materials provided by Public Library of Science. Note: Materials may be edited for content and length.


Cite This Page:

Public Library of Science. "Threatened Atlantic Leatherback Turtles Split Into Two Groups To Forage, Isotope Analysis Suggests." ScienceDaily. ScienceDaily, 26 March 2008. <www.sciencedaily.com/releases/2008/03/080325203447.htm>.
Public Library of Science. (2008, March 26). Threatened Atlantic Leatherback Turtles Split Into Two Groups To Forage, Isotope Analysis Suggests. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2008/03/080325203447.htm
Public Library of Science. "Threatened Atlantic Leatherback Turtles Split Into Two Groups To Forage, Isotope Analysis Suggests." ScienceDaily. www.sciencedaily.com/releases/2008/03/080325203447.htm (accessed August 21, 2014).

Share This




More Plants & Animals News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) — An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Newsy (Aug. 21, 2014) — According to a new study, spiders that live in cities are bigger, fatter and multiply faster. Video provided by Newsy
Powered by NewsLook.com
California Drought Stings Honeybees, Beekeepers

California Drought Stings Honeybees, Beekeepers

AP (Aug. 21, 2014) — California's record drought is hurting honey supplies and raising prices for consumers. The lack of rainfall means fewer crops and wildflowers that provide the nectar bees need to make honey. (Aug. 21) Video provided by AP
Powered by NewsLook.com
Possible Ebola Patient in Isolation at California Hospital

Possible Ebola Patient in Isolation at California Hospital

Reuters - US Online Video (Aug. 20, 2014) — A patient who may have been exposed to the Ebola virus is in isolation at the Kaiser Permanente South Sacramento Medical Center. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins