Minke whale

Distribution

Minke whales are widely distributed through most tropical, temperate and polar regions²  from approximately 65°S to 80°N³. Common minke whales are found in all ocean basins, with the dwarf minke whale subspecies more or less limited to the Southern Hemisphere.  Antarctic minke whales generally occur between 60 degrees South and the ice edge, although they can also occur inside the pack ice, making them difficult to study⁴.

Common minke whales are native to the following countries and territories: Anguilla; Antarctica; Antigua and Barbuda; Argentina; Australia; Bahamas; Bangladesh; Belgium; Bermuda; Bonaire, Sint Eustatius and Saba (Saba, Sint Eustatius); Brazil; Canada; Cape Verde; Chile; China; Cuba; Curaçao; Denmark; Dominica; Dominican Republic; Ecuador; Faroe Islands; France; French Guiana; Gambia; Greece; Greenland; Guadeloupe; Iceland; Indonesia; Ireland; Israel; Italy; Japan; Korea, Democratic People's Republic of; Korea, Republic of; Mauritania; Mexico; Morocco; Mozambique; Netherlands; New Caledonia; New Zealand; Norway; Papua New Guinea; Portugal; Puerto Rico; Russian Federation; Saint Martin (French part); Saint Pierre and Miquelon; Senegal; Sint Maarten (Dutch part); South Africa; Spain; Svalbard and Jan Mayen; Sweden; Taiwan, Province of China; Thailand; Tunisia; Turks and Caicos Islands; United Kingdom; United States; Uruguay; Virgin Islands, British; Virgin Islands, U.S.; Western Sahara:

Antarctic minke whales are native to the following countries or territories: Antarctica; Argentina; Australia; Brazil; Chile; French Southern Territories; Namibia; New Zealand; Peru; South Africa; South Georgia and the South Sandwich Islands; Uruguay

Biology and Ecology

Feeding

Common minke whales have varied diets, with many populations feeding on a vairety of small schooling fish ranging from anchovies to mackerel, herring, capeline and cod.  Some populations are also known to eat plankton, and krill is an important prey species for common minke whales off of Greenland.  Antarctic minke whales rely almost exclusively on krill – as do so many other species of blaeen whale that feed in Antarcitc waters².

Social structure reproduction and growth

Minke whale seasonal movements are less predictable and less well defined than many other species of baleen whales that have a very clear seasonal migratin pattern between summer feeding grounds and winter breeding grounds.  Although there may be some seasonal movement in some pouplations, breeding can occur year-round, and calves are born roughly 10 months after conception.  Calves remain with their mothers for 5-6 months, and females reach the age of reproduction at 7-8 years.  Female minke whales appear to be able to give birth to one calf every year, unlike many other baleen whales that produce only one calf every 2-3 years^2,5.

Threats and conservation status

Natural predators

Killer whales are the only known natural predator of minke whales. In fact, minke whales may form a major component of the diet of some forms of killer whales in the Antarctic². 

Human induced threats

Like most species of whales and dolphins, minke whales can become entangled in fishing gear^6,7.  Minke whale bycatch appears to be particularly high off the coasts of Japan and Korea³. Another potential threat is the  bioaccumulation of contaminants like organochlorines and DDT in minke whale blubber.^8-10 

Conservation status

Considered too small and too fast to be worth hunting, minke whales were overlooked by most whalers throughout the 19^th and 20^th centuries, and only became the focus of intensive whaling efforts when most other species were severely depleted and difficult to locate. As such, most minke whale populations were less severely affected by whaling than other species².  Today however, they are one of the few species of whale to still be hunted in significant numbers in countries that have lodged objections to the current IWC moratorium on whaling, such as Iceland and Norway, and by the Japanese who conduct scientific whaling programmes in the Antarctic and North Pacific.

Common minke whales are difficult to assess globally due their diffuse distribution.  However, they are designated as Least Concern under the IUCN Red List for threatened species, due primarily to the fact that they were less depleted by commercial whaling than other baleen whale species.   Some populations are subject to annual hunts which are deemed to be sustainable by the countries that implement the hunts (Iceland, Norway, and Japan).

Antarctic minke whales are considered Data Deficient under the IUCN Redlist.  Currently  they appear to number over 500,000^3,15.  Analyses revealed that their numbers increased from 1930 until the mid-1970s, declined over the period from the mid-1970s until about 1988, and then remained more or less stable over the past 20 years^11 6. In other words, the abundance estimated during the 1991/92 – 2003/04 southern hemisphere summer seasons was about 30% lower than that estimated during the 1985/86-1990/91 southern summer seasons¹⁵. .³  The reasons for this have not fully been explained.  Antarctic minke whales are listed under Appendix II on the convention on  Migratory Species (CMS). The eastern North Atlantic as well as the eastern north Pacific subspecies are included in Appendix II of CMS.

Minke whales and whale watching

Please see the IWC Whalewatching Handbook

Conservation status

Although gray whales have been legally protected from commercial whaling since the moratorium established by the International Convention for the Regulation of Whaling, a limited catch of eastern gray whales by aboriginal communities for cultural and subsistence purposes is permitted.  Most of these catches are made in Chukotka, Russian Federation, but a small portion of the IWC catch limit is allocated to the United States. 

The gray whale sub-population that feeds near Russia’s Sakhalin Island and Kamchatka Peninsula in the western Pacific is one of the smallest whale populations in the world.  Intensively hunted in the first half of the 20^th century, western gray whales are still listed by IUCN as Critically Endangered. Numbers off Sakhalin have slowly increased from an estimated 115 animals in 2004 to 174 in 2015⁷.  Although the increase gives cause for hope, the small  number of reproductive females in the population, ongoing pressures from oil and gas development near their prime feeding grounds and the risk of entanglement or entrapment in fishing gear off Japan¹ and elsewhere in Asia are of great concern for the eventual recovery of gray whales in the western Pacific.

The eastern population appeared to recover relatively quickly after protection from commercial whaling.  The population reached nearly 30,000 in 1997/98, but then dropped to roughly 18,000 following a mass mortality event in 2000-2002. Stranded and live whales observed at that time were alarmingly thin, and the mass die-off is thought to have been linked to food shortages resulting from a possibly climate –change related reduction in productivity on their feeding grounds¹ or from unusual persistence of ice cover which prevented access to primary feeding grounds⁸.  This population (which is taken to generally represent the species as a whole) is designated as Least Concern on the IUCN Red List of threatened species.

Gray whales and whale watching

Please see the IWC Whalewatching Handbook