Scientists use a suction cup to humanely tag a minke whale. The NSF-funded analysis, which was carried out off the Antarctic Peninsula, was carried out below Nationwide Marine Fisheries Providers allow 808-1735 and Antarctic Conservation Act allow 2009-Zero14. Video courtesy of Ari Friedlaender.
Minke whales dive below sea ice to gobble up krill at unprecedented charges
By Peter Rejcek, Antarctic Solar Editor
Posted September 5, 2014
The primary research to characterize the feeding habits of minke whales within the Antarctic has discovered that they’ll forage slightly below sea ice – the one such species to reveal that capacity – and does so at a prodigious charge.
The analysis, revealed within the The Journal of Experimental Biology, noticed that Antarctic minke whales (Balaenoptera bonaerensis) will lunge after their prey as many as 24 occasions per dive, twice that of their baleen whale cousin, the humpback (Megaptera novaeangliae), and as much as six occasions greater than world’s largest animal, the blue whale (Balaenoptera musculus).
“They lunge over 100 occasions an hour, nearly as soon as each 30 seconds,” mentioned Ari Friedlaender , an affiliate professor at Oregon State University’s Marine Mammal Institute , in a press release from The Company of Biologists , a nonprofit group that publishes The Journal of Experimental Biology, amongst different scientific publications.
Friedlaender is the most recent co-principal investigator on the Palmer Long Term Ecological Research (LTER) program, an ongoing research of the altering ecosystem alongside the western facet of the Antarctic Peninsula. The Palmer LTER program not too long ago added whale analysis to its suite of ongoing research. [See earlier article — Leaping into new territory: Palmer LTER adds whales to marine ecosystem study of Antarctic Peninsula.]
A lot of the work by Friedlaender and colleagues within the Antarctic has targeted on the less-elusive and extra plentiful humpback whale, making new discoveries about its feeding and migratory behaviors. [See earlier article — Delayed response: Humpback whales found to remain in Antarctic feeding grounds longer than expected.]
Nevertheless, throughout the 2012-2013 austral summer time, scientists aboard the analysis vessel Level Sur chanced upon a pod of 35 to 40 minke whales in Wilhelmina Bay, a picturesque bay identified for its humpback whale congregations, in addition to giant numbers of krill, seals and penguins.
“We very not often see these giant teams, so we knew that this was a rare case,” Friedlaender mentioned. Scientists had been capable of maneuver a ship among the many torpedo-shaped mammals, which gave the impression to be socializing throughout the encounter, and deploy tags that document details about their actions and underwater communications.
One of many tags used is in regards to the measurement of a paperback novel, with sensors and a tough drive. The devices are able to recording the animal’s acceleration, motion, heading and even vocalizations.
The group ended up accumulating almost 30 hours of dive information, together with 650 dives and almost three,000 feeding occasions. The group – together with researchers from Stanford University, Duke University and the Australian Antarctic Division – discovered that not solely do minke whales feed extra usually per dive than some other whale, however that a few of their diving habits can also be distinctive.
The minkes had been noticed swimming simply beneath the floor of the water, feeding at an extremely excessive charge, skimming the underside of the ocean ice.
“The whales had been feeding simply beneath the floor the place the ocean ice meets the water and the place the krill had been aggregating,” Friedlaender mentioned.
The observations are necessary details about the ecology of this little-understood predator within the Antarctic marine ecosystem. They’re additionally important given the speedy warming underway alongside a part of the Antarctic Peninsula, the place subantarctic local weather and species are migrating south.
Sea ice, particularly, is nearly disappearing, with winter length lower down by three months in some areas.
“Sea ice within the space across the Antarctic Peninsula has decreased dramatically within the final 30 years,” Friedlaender famous. “But we have no idea how crucial the ocean ice is as a habitat for the whales.”
Friedlaender instructed Science information on-line that the noninvasive strategies employed by his group reveal that culling animals for analysis, such because the controversial Japanese whaling program within the Southern Ocean, isn’t obligatory.
“We discovered extra in two weeks of learning these animals within the Antarctic than the Japanese have ever produced,” Friedlaender says. “There are methods to check these animals and their feeding habits with out taking them out of the image.”
NSF-funded analysis on this article: Ari Friedlaender, Douglas Nowacek and David Johnston, Duke College, Award No. 1250208 . Analysis was carried out below Nationwide Marine Fisheries Providers allow 808-1735 and Antarctic Conservation Act allow 2009-Zero14.