Fin Whale

The fin whale is the second-largest species of whale. It is found throughout the world’s oceans. It gets its name from an easy-to-spot fin on its back, near its tail.

Like all large whales, fin whales were hunted by commercial whalers, which greatly lowered their population. Whalers did not target them at first, because of they were fast and lived in open ocean habitats. But, as whaling methods modernized with steam-powered ships and explosive harpoons, and whalers over-hunted other species of whales they had used for oil, bone, and fat, whaling turned to fin whales, killing a huge number during the mid-1900s—725,000 in the Southern Hemisphere alone.

Whaling is no longer a major threat for this species. (Commercial whaling ended in the 1970s and 1980s, though some hunting continues today in Greenland through subsistence whaling allowances from the International Whaling Commission.) Today, the biggest threat comes from vessel strikes. The fin whale is listed as endangered under the Endangered Species Act and depleted under the Marine Mammal Protection Act.

NOAA Fisheries and its partners are dedicated to conserving and rebuilding the fin whale population. We use innovative techniques to study, protect, and rescue these endangered whales. We engage our partners as we develop regulations and management plans that foster healthy fisheries and reduce the risk of entanglements, create whale-safe shipping practices, and reduce ocean noise.

A fin whale has a sleek, streamlined body with a V-shaped head. It has a tall, hooked dorsal fin, about two-thirds of the way back on the body, that rises at a shallow angle from the back. Fin whales have distinctive coloration: black or dark brownish-gray on the back and sides, white on the underside. Head coloring is asymmetrical—dark on the left side of the lower jaw, white on the right-side lower jaw, and the other way around on the tongue. Many fin whales have several light-gray, V-shaped “chevrons” behind their heads; on many of them, the underside of the tail flukes is white with a gray border. These markings are unique and can be used to identify Individual fin whales.

Fin whales are fast swimmers, and are often found in social groups of two to seven. In the North Atlantic, they are often seen feeding in large groups that include humpback whales, minke whales, and Atlantic white-sided dolphins.

During the summer, fin whales feed on krill, small schooling fish (including herring, capelin, and sand lance), and squid by lunging into schools of prey with their mouth open, using their 50 to 100 accordion-like throat pleats to gulp large amounts of food and water. They then filter the food particles from the water, using the 260 to 480 baleen plates (long, flat plates made of fingernail-like material) they have in place of teeth on each side of the mouth. Fin whales fast in the winter while they migrate to warmer waters.

Like other baleen whales, fin whales also skim the water, taking in huge volumes of water. When they close their mouths, the water is pushed out through the baleen and the prey is caught on the inside of the baleen. A fin whale eats up to 2 tons of food every day this way.

Fin whales are found in deep, offshore waters of all major oceans, primarily in temperate to polar latitudes. They are less common in the tropics. They occur year-round in a wide range of locations, but the density of individuals in any one area changes seasonally. Most migrate from the Arctic and Antarctic feeding areas in the summer to tropical breeding and calving areas in the winter. The location of winter breeding grounds is not known. Fin whales travel in the open seas, away from the coast, so they are difficult to track. There are three named subspecies of fin whale:

• B. physalus physalus in the North Atlantic and North Pacific.
• B. physalus quoyi in the Southern Ocean.
• B. physalus patachonica in the mid-latitude Southern Ocean.

In fact, most experts consider the B. physalus physalus in the North Atlantic and the North Pacific to be separate subspecies. The two populations rarely (if ever) mix, and there are geographical stocks within these ocean basins. Fin whales are migratory, moving seasonally into and out of feeding areas near the poles, but the overall migration pattern is complex and likely varies by region, and specific routes have been documented for some populations. Acoustic recordings from passive-listening hydrophone arrays indicate a southward “flow pattern” in the fall from the Labrador-Newfoundland region, past Bermuda, and into the West Indies. There may be resident groups of fin whales in some areas, such as the Gulf of California, the East China Sea, and the Mediterranean Sea.

Little is known about the social and mating systems of fin whales. As with other baleen whales, long-term bonds between individuals are rare.

Fin whales have long lives: they reach physical maturity at about 25 years, and their maximum lifespan is about 90 years. Males become sexually mature at 6 to 10 years of age and females at 7 to 12 years of age. After 11 to 12 months of gestation, a pregnant female gives birth to a single calf in tropical and subtropical areas during midwinter. Newborn calves are about 18 feet long, and weigh 4,000 to 6,000 pounds.

Fin whales sometimes mate with blue whales and hybrids have been documented.

Vessel Strikes

Inadvertent vessel strikes can injure or kill fin whales. The projected increase in ship traffic arising from the opening of trans-polar shipping routes (as arctic sea ice continues to decline) will increase the risk of vessel strike, and also increase ambient noise and pollution.

Entanglement

Fin whales can become entangled in fishing gear, either swimming off with the gear attached or becoming anchored. They can become entangled in many different gear types, including traps, pots, or gillnets. Once entangled, whales may drag and swim with attached gear for long distances, ultimately resulting in fatigue, compromised feeding ability, or severe injury, which may lead to reduced reproductive success and death.

Ocean Noise

Underwater noise threatens whale populations, interrupting their normal behavior and driving them away from areas important to their survival. Increasing evidence suggests that exposure to intense underwater sound in some settings may cause some whales to strand and ultimately die.