Minke whales extreme feeding habits observed for first time

first_img Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe One overcast morning in Antarctica, scientists caught a lucky break when they were able to cruise their small boat right into a group of about 40 minke whales. Working quickly, they attached data-gathering tags to as many of the normally elusive animals as they could—something no one had ever done before. Now, a year and a half later, data from the auspicious encounter show that minke whales have staked out a unique ecological niche that no other baleen whale can take advantage of: hunting krill under sea ice.With the sleek silhouette of a torpedo and measuring about  6 meters long, minkes are the smallest of the baleen whales. Normally, Antarctic minkes travel solo or in small groups, keeping well away from people and not lingering at the surface. Consequently, little is known about them, despite their being the most common whale in Antarctica and the objects of Japan’s controversial scientific whaling program.On the day the scientists cruised into the group, though, the minkes let them get close enough to attach data-gathering tags to their bodies. The team high-fived and hugged when they stuck the first tag onto one of the whales and “just went crazy” when it was still attached to its host’s back after a nerve-wracking dive beneath an ice floe, says Ari Friedlaender, a marine mammal ecologist at Oregon State University’s Marine Mammal Institute in Newport, who led the team. Click to view the privacy policy. Required fields are indicated by an asterisk (*) Emailcenter_img Sign up for our daily newsletter Get more great content like this delivered right to you! Country Friedlaender’s team managed to tag nine minkes that day and several more over the next few days. Most of the whales carried satellite transmitter tags that gathered location data, but two carried special tags suction-cupped to their skin that recorded pressure, temperature, acceleration, and magnetic field. Together, the suction-cup tags gathered 26 hours of data, including 650 dives and nearly 3000 feeding events.The tag data showed that the minkes did most of their feeding under the sea ice, often skimming just below the frozen water while rapidly snapping up krill swarms—a feeding style seen in no other whale, Friedlaender and his colleagues report online today in The Journal of Experimental Biology. Bigger, less maneuverable whales just can’t do that. Eighteen-meter-long humpbacks, for instance, are Antarctica’s other abundant baleen whales, but they stick to feeding in the open water and the edges of the sea ice. Dining separately may be what lets the two species coexist in Antarctica, Friedlaender says. But as Antarctic sea ice melts, minkes may find themselves with a smaller niche and suddenly competing for food with their larger cousins, spelling trouble for the species.The tagged minkes also gulped down a remarkable number of mouthfuls of krill per dive compared with other baleen whales, which all catch prey using a behavior known as lunge feeding. The minkes lunged up to 24 times during a single dive, nearly once every 30 seconds. By contrast, blue whales, the largest baleen whales, can lunge only a few times during a dive because they gulp down much larger mouthfuls relative to their body size, resulting in immense drag. “Minke whales feed in [an] extreme manner relative to all other baleen whales,”  Friedlaender says.The new information is “a big piece of the puzzle that was missing” and it neatly confirms scientists’ predictions about how lunge feeding scales with baleen whale body size, says Robert Shadwick, a comparative physiologist who studies whales’ feeding mechanisms at the University of British Columbia, Vancouver, in Canada, and was not involved in the research. Before this study, scientists had good data on lunge feeding in large and medium, but not small, baleen whales. Shadwick adds that simply attaching recording devices to the fast, maneuverable minkes under harsh Antarctic conditions is a feat in its own right that opens new research possibilities.Friedlaender says his research casts doubt on Japan’s scientific whaling program, which has purported to study minke feeding biology and has killed between 240 and 860 of the animals every year since 1988. “We learned more in 2 weeks of studying these animals in the Antarctic than the Japanese have ever produced,” Friedlander says. “There are ways to study these animals and their feeding behavior without taking them out of the picture.”The International Court of Justice halted the minke hunt in March, saying it was not structured to meet its stated scientific goals. However, the Japanese are reportedly revamping their program to resume hunting later this year.last_img

Leave a Reply

Your email address will not be published. Required fields are marked *