Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Whale-sized genetic study largest ever for Southern Hemisphere humpbacks

15.10.2009
DNA from more than 1,500 whales examined

After 15 years of research in the waters of the South Atlantic and Indian Oceans, scientists from the Wildlife Conservation Society, the American Museum of Natural History, and an international coalition of organizations have unveiled the largest genetic study of humpback whale populations ever conducted in the Southern Hemisphere.

By analyzing DNA samples from more than 1,500 whales, researchers can now peer into the population dynamics and relatedness of Southern Hemisphere humpback whales as never before, and help inform management decisions in the sometimes politically charged realm of whale conservation.

The results of the massive analysis appear in PLoS One, an interactive open-access journal for scientific and medical research. Other contributors to the study include: Columbia University; University of Pretoria; Environment Study of Oman; Instituto Baleia Jubarta and PURCS (Brazil); University of Cape Town; Marine and Coastal Management (South Africa); Faculdade de Biociências; Agence Nationale des Parcs Nationaux (Gabon); Association Megaptera (France); Université de La Rochelle (France).

"Humpback whales are perhaps the most studied species of great whale in the Northern Hemisphere, but many of the interactions among Southern Hemisphere populations are still poorly understood," said Dr. Howard Rosenbaum, Director of the Wildlife Conservation Society's Ocean Giants Program and lead author of the study. "This research illustrates the vast potential of genetic analyses to uncover the mysteries of how humpbacks travel and form populations in the southern ocean basins."

So little is known about southern ocean basin humpbacks that researchers initially used old whaling records for insights into whale population boundaries.

Researchers collected skin samples from 1,527 whales from fourteen sampling sites from the Southwestern and Southeastern Atlantic Ocean, and the Southwestern and Northern Indian Oceans. The populations are known as Breeding Stocks A (Southwest Atlantic Ocean), B (Southeast Atlantic Ocean), C (Southwest Indian Ocean), and X (Northern Indian Ocean), based on information amassed and designated by the International Whaling Commission, including data from 19th and 20th Centuries commercial whaling.

The scientists collected samples from living whales with biopsy darts fired from crossbows. The darts harmlessly bounce off the marine mammals as they surface to breathe. Samples came also from skin which is continually sloughed off by the animals and collected by the research teams.

Once collected, the samples were brought to the lab at the AMNH Sackler Institute for Comparative Genomics and examined through a technique called polymerase chain reaction (PCR), which "amplifies" specific regions of DNA which then can be used to statistically inform researchers about gene flow between populations. The research team specifically focused on mitochondrial DNA, which is passed through maternal lines of a population, in order to measure interchange between groups.

The findings so far have revealed:

The highest rate of gene flow between populations is between whales that breed on either side of the African continent (Breeding Stocks B and C), with an estimated one or two reproductively active whales every year swimming from one ocean to join whales in another breeding ground. Authors of the current study previously identified the same individual whale in both Atlantic and Indian Ocean breeding grounds at different times, the first recorded instance of a humpback whale traveling between these two oceans.

A lower rate of gene flow between humpbacks breeding on opposite sides of the Atlantic (one population along coastal Brazil and the other along the coast of Southern Africa). While no individual whales have been detected traveling across the Southern Atlantic to both breeding grounds, genetic similarities reveal a slight degree of populations interacting. Interestingly, an examination of humpback whale songs between the two populations are similar, another hint at interchange between the two groups, most likely in the whales' feeding grounds in Antarctic waters.

Breeding Stock X, which inhabits the northern Indian Ocean off the Arabian Peninsula, numbers fewer than 200 whales and is the most distinct in terms of genetics and migratory behavior. Unlike the other humpback populations, it is non-migratory and only distantly related to the nearest group of humpbacks (which breed off Madagascar and the eastern coast of Southern Africa). As a small, insular group, the "X" population is unique and therefore a conservation priority.

In addition to examining the population boundaries of humpbacks in the Southern Hemisphere, the study also gives scientists some insight into the mysterious and mercurial nature of marine ecosystems, with currents, water depth, and other unseen factors serving as shifting conduits and barriers between marine populations and ecosystems.

On an interesting historical note, Rosenbaum and his co-authors used old whaling records to guide their research on whale populations. One set of charts—titled "The Distribution of Certain Whales as Shown by Logbook Records from American Whale Ships"—was compiled by Charles Townsend of the New York Zoological Society (now WCS) and recorded the locations of more than 50,000 whale captures (including humpback whales) between 1761-1920. According to the charts, many humpback whales were captured in the Gulf of Guinea, Southeastern African and northeastern Madagascar, the same locations where humpbacks congregate today. "Townsend was attempting to identify distribution and possible boundaries between whale populations or 'breeding stocks,'" noted Rosenbaum. "We're still trying to answer the same question with molecular technology in concert with whaling logbook records."

"Understanding the needs of humpbacks and other whale species can be challenging in terms of direct observations of these animals in the wild. Molecular technology gives us a window into the lives of whales that can help us understand the ecological forces shaping their movements and distribution," added Rosenbaum. "We can also use our findings to inform management decisions for a species that is only now beginning to recover from centuries of commercial whaling."

The humpback whale is a baleen whale that grows up to approximately 50 feet in length. The species has distinctively long pectoral fins and a head with knobs on the top and lower jaw. The humpback is also known for its acrobatics (such as full body breaching) and haunting songs, typically sung by males and possibly a mating behavior. The slow-swimming species was hunted commercially until the International Whaling Commission protected the species globally in 1966. Current estimates for humpback whale numbers are widely debated. While they are recovering, total population sizes may only perhaps be a small percent of the original global population.

This study was generously supported by The Eppley Foundation For Research, Flora Family Foundation, and Lenfest Ocean Program.

John Delaney | EurekAlert!
Further information:
http://www.wcs.org

More articles from Ecology, The Environment and Conservation:

nachricht Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung

nachricht Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Quantum optical sensor for the first time tested in space – with a laser system from Berlin

For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.

According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

Tracking movement of immune cells identifies key first steps in inflammatory arthritis

23.01.2017 | Health and Medicine

Electrocatalysis can advance green transition

23.01.2017 | Physics and Astronomy

New technology for mass-production of complex molded composite components

23.01.2017 | Process Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>