Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Humpback Whales Staying in Antarctic Bays Later into Autumn

31.07.2012
Large numbers of humpback whales are remaining in bays along the Western Antarctic Peninsula to feast on krill late into the austral autumn, long after their annual migrations to distant breeding grounds were believed to begin, according to a new Duke University study.
The study, published today in the journal Endangered Species Research, provides the first density estimates for these whales in both open and enclosed habitats along the peninsula in late autumn.

It suggests that the little-studied bays are much more important late-season feeding grounds for humpback whales than scientists previously thought. It also highlights changes that are occurring in the region in response to the increasingly delayed arrival and reduced extent of annual winter sea ice cover, associated with rapid climate change.

“The old dogma is that by late autumn, the ice is heading in and the whales have headed out. But 70 percent of our surveying took place in waters with no ice, and we detected 371 groups of humpback whales over a 654-kilometer survey area, with density estimates of up to 1.75 whales per square kilometer,” said David W. Johnston, research scientist at Duke’s Nicholas School of the Environment and lead author of the paper.

At that density, Johnston said, “if you were to walk to the bridge of a ship and look around, you’d spot two whales within 500 meters of the boat. That’s higher than anyone expected.”

The scientists found the highest densities of whales in narrow, enclosed sections of Wilhelmina Bay, Andvord Bay and the Errera Channel. They found the lowest densities – as low as 0.02 whales per square kilometer – in the open water of the adjacent Gerlache Strait, which separates the Palmer Archipelago from the Western Antarctic Peninsula.

They conducted the study aboard the National Science Foundation (NSF) research vessel Laurence M. Gould in late April through early June of 2009. NSF funded the study.

Johnston’s co-authors are Ari S. Friedlaender, research scientist; Andrew J. Read, Rachel Carson Associate Professor of Marine Conservation Biology; and Douglas P. Nowacek, Repass-Rodgers University Associate Professor of Marine Conservation Technology. All four are stationed at the Duke University Marine Laboratory. Nowacek holds a joint appointment as associate professor of electrical and computer engineering at Duke’s Pratt School of Engineering. The study is online at http://www.int-res.com/articles/esr_oa/n018p063.pdf.

Scientists have long known the waters around the Western Antarctic Peninsula are important foraging grounds for humpback whales that feed on swarms of shrimp-like krill there, but previous studies have been conducted earlier in the season or in open waters farther from land.

“Establishing the autumn density of humpback whales in the inshore regions of the Western Antarctic Peninsula is crucial for understanding the role they play in this rapidly changing ecosystem,” said Friedlaender. “Our results provide a new perspective on the magnitude of predator-prey relationships in the region as the Antarctic winter sets in.

Being the first to estimate densities in the peninsula’s narrow in-shore waters was a challenge, Johnston said, because the line-transect techniques and distance sampling methods scientists traditionally use for this type of study weren’t well suited to the bays’ tight quarters, tricky currents and jutting shorelines.

“We had no idea that the whales were going to be packed up in these narrow channeles and passages. We had to think on our feet a bit and use alternative sampling approaches and incorporate data from other portions of the project,” he said. For instance, data collected from tagging the whales and tracking their underwater movements turned out to be inordinately useful for estimating densities, too.

“Once we knew their dive behaviors, we could establish how likely it was that we might miss them as we were traveling along the surface of the water,” Johnston said. “That’s not something we would have been able to do using only the traditional methods.”

Note: Photos from the research expedition to study humpback whales are available at http://www.nicholas.duke.edu/news/antarctic-2012

Tim Lucas | EurekAlert!
Further information:
http://www.duke.edu

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: 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...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

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

Helmholtz International Fellow Award for Sarah Amalia Teichmann

20.01.2017 | Awards Funding

An innovative high-performance material: biofibers made from green lacewing silk

20.01.2017 | Materials Sciences

Ion treatments for cardiac arrhythmia — Non-invasive alternative to catheter-based surgery

20.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>