Subscribe free to our newsletters via your
. Earth Science News .




Subscribe free to our newsletters via your




















WHALES AHOY
Antarctic whales and the krill they eat
by Staff Writers
Washington DC (SPX) May 13, 2016


These are three fin whales diving up in a lunge feeding event in the Drake Passage. Image courtesy ITAW and Carsten Rocholl. For a larger version of this image please go here.

The Western Antarctic sector of the Southern Ocean is the regular feeding ground of a large number of fin and humpback whales of the Southern Hemisphere. Around 5,000 fin whales likely migrate to its ice-free waters during summer, along with at least 3,000 humpback whales.

These estimates follow a ship-based helicopter survey of whales in Antarctic waters. A net trawl survey for krill* was also conducted to see if the distribution of these whales and specific krill species are connected. The study was led by Helena Herr of the University of Veterinary Medicine Hannover in Germany, and is published in a special issue on "Antarctic Peninsula Shelf Biology" in Springer's journal Polar Biology.

Herr's team produced distribution maps that predict the densities in which humpback (Megaptera novaeangliae) and fin whales (Balaenoptera physalus) likely occur in the Bransfield Strait and Drake Passage.

It was found that the two whale species do not share the same habitat or feeding grounds around the West Antarctic Peninsula. An estimated 3,024 humpback whales frequented the coastal parts of the Bransfield Strait in summer 2013, while at least 4,898 endangered fin whales were found along the shelf edge in the Drake Passage.

The krill survey shows that Euphausia superba is the most widely distributed and abundant source of food available to whales in the area. The krill type Euphausia crystallorophias occurs sporadically in smaller numbers near the coast, and Thysanoessa macrura generally beyond the shelf edge.

The relationship between whales and the krill they feed on is not a simple one. At the time of the survey, fin whales fed in an area dominated by Thysanoessa macrura. They are also known to feed on Euphausia superba. Fin whales therefore seem to opportunistically feed on whatever prey aggregates around the shelf edge.

There isn't a clear relationship between humpback whales and the presence of a particular krill species either. The whales seemed to be located in all areas of the Bransfield Strait regardless of how much krill was available.

Humpback whales did however tend to occur in sectors with at least a medium concentration of Euphausia superba. Humpback whales seem to have adopted migration patterns and foraging strategies that lead them to areas likely to provide, on average, sufficient amounts of prey.

"In the light of increasing effort by the commercial krill fishery and climate change-related effects on krill biomass, dedicated surveys that target both krill and their main predators, such as baleen whales, need to be undertaken concurrently.

"This is to monitor and ensure that habitats in the Southern Ocean will continue to support a humpback whale population that has just touched pre-exploitation numbers," says Herr.

Efforts should also be strengthened to investigate the ecology and feeding strategies of endangered Southern Hemisphere fin whales, since little is known about their connection to and dependency on local prey stocks.

Herr, H. et al. (2016). Horizontal niche partitioning of humpback and fin whales around the West Antarctic Peninsula: evidence from a concurrent whale and krill survey, Polar Biology, DOI 10.1007/s00300-016-1927-9

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
Springer
Follow the Whaling Debate






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
WHALES AHOY
Study links baby dolphin deaths to BP oil spill
Miami (AFP) April 12, 2016
An unusually high number of baby dolphins were found dead in the Gulf of Mexico following the 2010 Deepwater Horizon disaster, and a study Tuesday blamed chronic illnesses in mothers exposed to the oil. The study probing dolphin deaths from 2010-2014 in the coastal areas of Louisiana, Mississippi and Alabama was published in the journal Diseases of Aquatic Origin. Researchers found "subs ... read more


WHALES AHOY
Belgian prisons 'like North Korea' as strike crisis hits

Rush on pillows at Canada evacuation center

Tensions simmer at Canada fire evacuee centers

Haiti preparing for major earthquake, tsunami

WHALES AHOY
Design tool enables novices to create bendable input devices for computers

Molybdenum disulfide holds promise for light absorption

Accelerating complex computer simulations: thinking beyond ones and zeros

Machine learning accelerates the discovery of new materials

WHALES AHOY
Sustainable seafood surging, but not everywhere: report

Rapid marsh bank sediment build up does not equate land loss resilience

Daily up and down of the plankton animals in the sea

Most streamflow in the upper Colorado River basin originates as groundwater

WHALES AHOY
The genetic history of Ice Age Europe

Influence of sea-ice loss on Arctic warming shaped by Pacific temps

Study finds ice isn't being lost from Greenland's interior

What lies beneath West Antarctica

WHALES AHOY
Agricultural ammonia emissions disrupt earth's delicate nitrogen balance

How algae could save plants from themselves

Study reveals genetic origins of carrots' orange color

Rising Carbon Dioxide Levels Will Help and Hurt Crops

WHALES AHOY
Over a dozen people killed in Uganda landslides

Landslides kill nearly 50 in Rwanda

World's shallowest slow-motion earthquakes detected offshore of NZ

Floods following drought worsen Ethiopian hunger

WHALES AHOY
Senegal's child beggars show limits of 'apptivism'

S.Africa may re-consider regulated rhino horn trade in future

Climate-exodus expected in the Middle East and North Africa

Severe drought forces Zimbabwe to sell off wildlife

WHALES AHOY
Drawing the genetic history of Ice Age Eurasian populations

Hominins may have been food for carnivores 500,000 years ago

Neandertals and Upper Paleolithic Homo sapiens had different dietary strategies

Chimp study explores the early origins of human hand dexterity




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement