The northern minke whale, Balaenoptera acutorostrata, is the smallest of the baleen whales at approximately 25-30 feet in length. We occasionally will see Minkes whales on our San Juan Islands whale watching and kayak tours. While its exhalations might sound similar to the breathing of surfacing orcas, minkes are distinct from Southern Resident orcas by their completely dark grey coloration, elongated and streamlined bodies, and small dorsal fins. In addition, their snouts are narrow and elongated, which differ from the blunt melon-like heads of orcas.
As a baleen whale species, minke whales feed on marine plankton, krill, and small fish such as sardines and herring. Instead of teeth, minkes possess tough, bristled plates in their mouths. Also known as “baleen”, these plates act as giant strainers that keep food in while water is expelled from their expandable throat cavities. Each whale has approximately 300 baleen plates in is mouth.
Minke whales are one of the most abundant baleen whales, and as such are a target for commercial whale hunting. While they can make dives for over 20 minutes, these whales usually surface to breath more frequently and thus are easily spotted from aboard large ships. Their predation by humans is still common in certain areas of the world, including Antarctic waters.
Most minke whales spotted in the inland coastal waters of Washington and British Columbia will be traveling singly or in small groups. On our kayaking and whale watching tours we have our best opportunities to see them off the west side of San Juan Island and on our four day kayak tour where we paddle to Jones Island. For the most part, these whales are shy of boat traffic and will often be more elusive than a large pod of orcas.
When sighting a minke whale, look for a low, dark back profile at the surface with a small, curved dorsal fin. Minke whales usually swim at speeds between 3-15 miles per hour, depending on their feeding patterns. While minkes are the smallest of baleen species, they can be extremely loud underwater – as loud, in fact, as a jet engine at takeoff (over 150 decibels)! These sounds may be used for echolocation or communication with other whales.
The two species of minke are the world’s most hunted whales. Japan targets about 950 a year for its “research” programs. Commercially, Norway issues quotas to hunt about 1,000 per year, while Icelandic boats catch about 50 per year. Greenland’s Inuit hunters can take up to 212 for subsistence purposes.
Estimates of minke numbers for the Southern Hemisphere are currently under scientific review, but current estimates put them at about 450,000. There are more than 145,000 in the North Atlantic and about 25,000 in the western North Pacific.