About The Species

Minke whales are members of the baleen whale family and are the smallest of the "great whales" or rorquals. They are the most abundant rorqual in the world, and their population status is considered stable throughout almost their entire range (especially when compared to other species of large whales). Commercial whaling practices may have reduced minke whale populations in the western North Pacific and the northeastern North Atlantic may have been reduced by as much as half. Commercial whaling’s overexploitation of other larger whale species, however, may have allowed minke whales to prosper from the lessened competition and increased availability of food resources. The scientific names for minke whales translate to: "winged whale," (Balaenoptera) "sharp snout" (acutorostrata). They received their common name from a Norwegian novice whaling spotter named Meincke, who supposedly mistook a minke whale for a blue whale. Minke whales in the United States are not endangered or threatened, but they are protected under the Marine Mammal Protection Act. NOAA Fisheries and its partners are dedicated to conserving minke whales. We use a variety of innovative techniques to study and protect this species.

Status

The taxonomy, or classification, of minke whales is complex because there are at least two recognized species: the northern or common minke whale (Balaenoptera acutorostrata) and the Antarctic minke whale (Balaenoptera bonaerensis).

The dwarf minke is currently considered a northern minke subspecies, but it could potentially be a third species (which has not received an official scientific name). There are also several other subspecies. The northern minke whale is divided into two distinct subspecies. The North Pacific (Balaenoptera acutorostrata scammoni) and the North Atlantic (Balaenoptera acutorostrata acutorostrata).

The International Whaling Commission recognizes two stocks in the North Pacific as being of concern: the J-stock (East China Sea, Sea of Japan, and Yellow Sea) and the O-stock (Pacific waters and Sea of Okhotsk). Only a very small number of eastern North Pacific animals were taken for subsistence by Alaska Natives. Recently, the estimated population of minke whales has come into question, and it is possible that some stocks have been depleted because of modern whaling and hunting.

The latest stock assessment reports for U.S. minke whale stocks include population estimates for each minke whale stock in U.S. waters.

Protected Status

CITES Appendix I 1 distinct population segment All stocks except West Greenland

CITES Appendix II 1 distinct population segment West Greenland stock

MMPA Protected Throughout Its Range

Appearance

The minke whale is the smallest baleen whale in North American waters. These rorquals have a relatively small, dark, sleek body that can reach lengths of up to about 35 feet and weigh up to 20,000 pounds. Females may be slightly larger than males. Minke whales have a fairly tall, sickle-shaped dorsal fin located about two-thirds down their back. Their body is black to dark grayish/brownish, with a pale chevron on the back behind the head and above the flippers, as well as a white underside. Calves are usually darker in coloration than adults. Minke whales vary in body size, patterns, coloration, and baleen (long, flat keratin plates that hang from the whale’s mouth in place of teeth) based on geographical location. They may vary individually as well. Northern minke whales are distinguished from other rorquals by their relatively small size and a well-defined white band located on the middle of their dark flippers. They have 230 to 360 short, white/cream colored baleen plates on each side of their mouth and 50 to 70 abdominal pleats are located along their throat. Dwarf minke whales are a subspecies of the northern minke whale, but they are significantly smaller in size, growing up to lengths of about 26 feet and weighing up to 14,000 pounds. Their baleen plates have a thin black border. Dwarf minke whales can also be distinguished from other minke whales by a bright white patch on the upper part of their dark pectoral fin that extends up towards the shoulder and back area. They also have a dark half-collar that wraps around the head and reaches the throat grooves. Antarctic minke whales have 200 to 300 baleen plates on each side of their mouths. Their pectoral flippers are usually solid gray with a white leading edge, and the noticeable band seen in the northern and dwarf form is generally absent. Unlike other minke whales, the color of their baleen is asymmetrical, with fewer white baleen plates on the left side than on the right side of the forward part of their mouth. The rest of their baleen plates are dark gray. Antarctic minke whales also have 22 to 38 abdominal pleats located along their throat.

Behavior and Diet

Minke whales are usually sighted individually or in small groups of two to three, but loose groupings of up to 400 animals have been seen in feeding areas closer to the poles. The segregation and distribution of these Northern Hemisphere whales suggests a complex social and population structure, but less is known about the populations in the Southern Hemisphere. Minke whales feed by side-lunging into schools of prey and gulping large amounts of water. Sea birds, attracted to the concentrated prey just below the surface, are sometimes associated with minke whale feeding and foraging. Minke whales opportunistically feed on crustaceans, plankton, and small schooling fish (e.g., anchovies, dogfish, capelin, coal fish, cod, eels, herring, mackerel, salmon, sand lance, saury, and wolfish). In the Southern Hemisphere, krill constitutes most of the diet for the Antarctic species, while the dwarf minke whale subspecies feeds on a combination of krill and myctophid fish. Minke whales are known to vocalize and create sounds that include clicks, grunts, pulse trains, ratchets, thumps, and recently discovered "boings." These distinct vocalizations can vary depending on species and geographic area. Minke whales are often recognized in the field by surfacing snout-first, with a small and weak—but visible—bushy blow that is about 6.5 to 10 feet high. Unlike other rorqual species, they do not raise their flukes out of the water when they are diving. When surfacing, they have a quick fluid movement, which creates spray (sometimes described as a "roostertail") when traveling at high speeds. Before deep dives, they may arch and expose much of their back and body in a high roll above the surface. These whales can dive for at least 15 minutes but regularly submerge for 6 to 12 minutes at a time. Minke whales are often active at the surface, and are commonly seen breaching. They frequently poke their heads above the surface (or, “spyhop”) in areas of mobile ice in the Arctic and Antarctic. At sea, these animals may be curious and approach vessels, especially those that are stationary.

Where They Live

Minke whales prefer temperate to boreal waters but are also found in tropical and subtropical areas. They feed most often in cooler waters at higher latitudes and can be found in both coastal/inshore and oceanic/offshore areas. Their distribution is considered cosmopolitan because they can occur in polar, temperate, and tropical waters in most seas and areas worldwide. Minke whales, like some other species of cetaceans, migrate seasonally and can travel long distances. Some animals and stocks of this species have resident home ranges and are not highly migratory. The distribution of minke whales varies by age, reproductive status, and sex. Older mature males are commonly found in the polar regions in and near the ice edge—often in small social groups—during the summer feeding season. Mature females will also migrate farther into the higher latitudes, but generally remain in coastal waters. Immature animals are more solitary and usually stay in lower latitudes during the summer. Minke whales in Alaskan waters are migratory, but animals in the inland waters of California/Oregon/Washington are considered "residents" because they establish home ranges. Northern minke whales have a widespread distribution in the Northern Hemisphere and are found throughout the northern Atlantic and Pacific Oceans. Their range extends from the ice edge in the Arctic during the summer to near the equator during winter. Dwarf minke whales are distributed close to the polar region in the Southern Hemisphere, especially during the summer months, but are more common in temperate and warmer waters of middle and lower latitudes. They are frequently reported in areas off of Australia (such as the Great Barrier Reef), South America and South Africa. The distribution of the Antarctic and dwarf minke species partially overlaps, mostly in the lower latitudes of the Antarctic minke's range (in the Southern Ocean). The Antarctic minke whale also has a similar distribution in the Southern Hemisphere and has been reported as far south as 78° south in the Ross Sea during the summer. In the southern Atlantic Ocean, Minke whales are usually found between 20° and 65° south. Immature individuals generally do not travel past 42° south. These whales migrate far distances seasonally, feeding in and around the ice edge during the summer and moving to mating/calving grounds during the winter (7° S to 35° south).

World map providing approximate representation of the minke whale's range.

Lifespan & Reproduction

Minke whales become sexually mature at around 3 to 8 years of age (7 to 8 years for Antarctic minke whales), which is about when they reach 23 feet in size. Mating and calving most likely occurs during the winter. After a gestation period of 10 to 11 months, females give birth to a single calf that is about 8 to 11.5 feet in length and weighs 700 to 1,000 pounds. The calf is weaned from nursing after 4 to 6 months. The reproductive interval for females is estimated at 14 months, but calving may occur annually. Mother-calf pairs are usually sighted in the lower latitudes of the wintering grounds, but they are much rarer in the summer feeding grounds closer to the poles. The estimated lifespan of minke whales is up to 50 years.

Threats

Whaling Historically, whalers have exploited minke whales since at least the 1930s. Hunters had previously overlooked them because of their relatively small size. Since commercial whalers started targeting minke whales, several thousand have been hunted in the Northern Hemisphere, and at least 100,000 have been killed in the Southern Hemisphere. In the past, these whales were commercially hunted by China, Iceland, Korea, Russia and Taiwan. Today, whaling countries such as Greenland, Japan, and Norway still take minke whales for food and for scientific research. Entanglement in Fishing Gear Minke whales get entangled in fishing gear, including groundfish trawls in Alaska, as well as drift and set gillnets off California/Oregon/Washington. They also become entangled in driftnets, gillnets, herring weirs, lobster traps, and tuna purse seine nets from numerous fisheries in waters of the Northeast and Mid-Atlantic United States and Canada. Ocean Noise Underwater sounds and anthropogenic noise are an increasing concern for baleen whales, such as minke whales, which use low-frequency sounds to communicate with one another and to locate prey. Vessel Strikes Inadvertent vessel strikes can injure or kill minke whales. Minke whales are vulnerable to vessel strikes throughout their range, but the risk is much higher in some coastal areas with heavy ship traffic. The projected increase in vessel traffic arising from the opening of trans-polar shipping routes (as Arctic sea ice continues to decline) will increase the risk of vessel strikes, ambient noise, and pollution in the Arctic.

Scientific Classification