Studying members of a large population of loggerhead sea turtles that nest on the Cape Verde islands off of West Africa, researchers have found an unexpected dichotomy in turtle behavior: While some turtles leave the nesting grounds to feed on bottom-dwelling sea life in shallow coastal waters, others leave Cape Verde to roam the much deeper open ocean along the African coast and exhibit a distinct feeding strategy. Interestingly, while adults compose both groups, the coastal feeding strategy correlates with larger animal size. These new findings revise our understanding of the turtle’s life history and indicate that a multifaceted approach to fishing regulation--in both coastal and oceanic waters--will be required to effectively conserve these animals.
The findings are reported by Brendan Godley and colleagues at the Marine Turtle Research Group at the University of Exeter in Cornwall, Michael Coyne of the Marine Geospatial Ecology Lab at Duke University, and other members of an international team of researchers. The paper appears in the May 23rd issue of Current Biology.
Past studies had indicated that the loggerhead sea turtle (Caretta caretta), which reaches sexual maturity at about 30 years of age, typically undergoes a shift from an oceanic juvenile stage to a shallow-water, coastal adult stage. But the new findings--obtained by newly-improved methods for satellite tracking of the adult turtles’ geographical movements and diving patterns--show that the sexually mature adult population also includes oceanic animals and thereby reveal that adults in the eastern Atlantic occupy very different habitats and undertake two distinct foraging strategies.
The differing strategies correlate with body size, which may be linked to the different diets of the two groups. Turtles migrating to shallow coastal waters-the so-called neritic environment-were larger, and they feed on the arthropods and mollusks that are normally abundant in this food-rich ecosystem. In contrast, adults foraging in the open ocean are smaller, have a more limited capacity for diving, and most likely feed on a somewhat different set of prey that includes small, floating plants and animals.
Importantly, the correlations in animal size and foraging strategy suggest that the majority of adults in the Cape Verde population may undertake the oceanic strategy, rather than the primarily coastal existence previously thought to characterize adulthood. This means that two adult populations will need to be monitored for conservation efforts. And critically--because commercial and artisanal fishing occur in both the open ocean and coastal waters--the findings indicate that appropriate measures will be needed to regulate fishing efforts to reduce by-catch in the different environments. The fact that the oceanic adults were found in a large area, including international waters and waters from Mauritania to Guinea Bissau, indicates that efforts toward regulation and population monitoring will need to take place on a large scale.
Multi-institutional collaboration uncovers how molecular machines assemble
02.12.2016 | Salk Institute
Fertilized egg cells trigger and monitor loss of sperm’s epigenetic memory
02.12.2016 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water
In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...
The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.
Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
02.12.2016 | Medical Engineering
02.12.2016 | Agricultural and Forestry Science
02.12.2016 | Physics and Astronomy