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!
Scientists team up on study to save endangered African penguins
16.11.2017 | Florida Atlantic University
Climate change: Urban trees are growing faster worldwide
13.11.2017 | Technische Universität München
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses