Conservationists from the Wildlife Conservation Society, the American Museum of Natural History, and other conservation and research groups have discovered that groups of dolphins in the western Indian Ocean do not mix freely with one another. In fact, dolphin populations are kept separate by currents and other unseen factors.
Specifically, the researchers have found that genetically distinct populations of the Indo-Pacific humpback dolphin may be formed in part by currents, surface temperature differences, and other environmental barriers, a finding made possible by using both genetic data from dolphins and environmental information from remote-sensing satellites.
The study appears in the advance online version of the journal Heredity. The study authors are: Martin Mendez of the American Museum of Natural History and the Wildlife Conservation Society; Ajit Subramaniam of Columbia University; Tim Collins of the Wildlife Conservation Society and the Environment Society of Oman; Gianna Minton of the Environment Society of Oman and the Institute of Biodiversity and Environmental Conservation, University Malaysia Sarawak; Robert Baldwin of the Environment Society of Oman; Per Berggren of Newcastle University; Anna Särnblad of Stockholm University; Omar A. Amir of the Institute of Marine Sciences, University of Dar es Salaam; Victor M. Peddemors of the University of KwaZulu-Natal and the Cronulla Fisheries Research Centre; Leszek Karczmarski of the University of Hong Kong; Almeida Guissamulo of Universidade Eduardo Mondlane, Museu de História Natural; and Howard C. Rosenbaum of the Wildlife Conservation Society.
The study represents a breakthrough in high-tech research on marine wildlife and a foundation for ensuring sound future management decisions on the Indo-Pacific humpback dolphin, a distant relative of the more familiar bottlenose dolphin. It is one of the first examinations of how environmental factors in marine environments can influence population structure in marine species, and can potentially enhance an understanding about the environmental factors that may drive the evolution of new species.
"Examining how environmental factors affect the population structure of marine species is a complex task. Doing this over entire regions is a challenge," said lead author Dr. Martin Mendez of the Sackler Institute for Comparative Genomics at the American Museum of Natural History. "Unlike studies of terrestrial species in easily observable environments, marine species are difficult to follow and the barriers they encounter are often invisible to us. Molecular technologies and remote sensing data can be combined to shed light on these mysteries."
The team started its examination of Indo-Pacific humpback dolphin populations using genetics, analyzing mitochondrial DNA data from more than 90 individual dolphins from the coastal areas of Oman, Mozambique, Madagascar, Tanzania, and South Africa. The scientists used this "genetic marker" to statistically measure gene flow between dolphin groups at different locations.
The researchers then compared their molecular findings with 13 years of data from NASA's satellites on environmental factors such as currents, temperature, turbidity, levels of chlorophyll, and dissolved organic matter.Dr. Mendez and his co-authors have succeeded in finding support for the hypothesis that environmental differences between regions could influence the population structure of marine species. Specifically, they found correlations between regional environmental differences and measurable genetic breaks between populations of dolphins from Mozambique and Tanzania in Africa, and Oman on the Saudi Arabian peninsula.
The researchers also found agreement on smaller spatial scales. Differences in temperature, chlorophyll, turbidity, and dissolved organic matter between regions also coincided with genetic differences between dolphin populations in Mozambique, Tanzania, and Oman. The two coastal regions without detectable genetic distinctiveness between dolphin populations—Mozambique and South Africa—also lacked significant environmental differentiation between them, a finding in agreement with the correlation of both genetic and environmental differences detected in other areas.
"With increasing development and potential threats to coastal habitats, understanding the population structure of the Indo-Pacific humpback dolphin in conjunction with environmental factors is an important step in formulating management recommendations and protection measures for the species," said Dr. Howard Rosenbaum, Director of the Wildlife Conservation Society's Ocean Giants Program.
Named for a distinctive hump under the dorsal fin of some individuals, the Indo-Pacific humpback dolphin grows up to 10 feet in length and ranges from dark gray to pink and/or white in color. The species generally inhabits coastal waters, deltas, estuaries, and occurs throughout the Indian Ocean basin to the coasts of Australia. The Indo-Pacific humpback dolphin is listed as "Near Threatened" by the International Union for Conservation of Nature (IUCN) and is threatened by habitat loss, disruption, and fishing activity.
John Delaney | EurekAlert!
Conservationists are sounding the alarm: parrots much more threatened than assumed
15.09.2017 | Justus-Liebig-Universität Gießen
A new indicator for marine ecosystem changes: the diatom/dinoflagellate index
21.08.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
21.09.2017 | Physics and Astronomy
21.09.2017 | Life Sciences
21.09.2017 | Health and Medicine