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New Jersey Endangered and Threatened Species Field Guide

Image of A Fin whale surfaces to breath.Zoom+ A Fin whale surfaces to breath. © Chris Buelow

Fin whale

Balaenoptera physalus

Species Group: Mammal

Conservation Status

State: Endangered

Federal: Endangered



The fin whale is a large baleen whale. It is the second largest animal alive today - only the blue whale is larger. It may reach a length of up to 75 feet in the Northern Hemisphere and 85 feet in the Southern Hemisphere. Adult females are larger than adult males. Fin whales can weigh up to 80 tons (160,000 pounds). It has a long, slender streamlined body that is primarily dark grey with a white underside. The fin whale's head is flat and there is a distinctive grayish-white chevron marking on the back behind the head. Its V-shaped snout has a single dorsal ridge running down its middle. Its mouth is also quite distinctive, with the right lower jaw lip white, in contrast to the black left lower jaw. Its upper right lip is often white while the left lips are dark. Such asymmetrical coloration is unique among whales.

Instead of teeth, it has great plates of horny baleen which extend from the upper jaw. These are used to strain food from large mouthfuls of water. It has two blowholes and grooves on the throat and chest. The baleen plates are white on the right side while the baleen on the left side are alternately striped yellowish-white and bluish-gray to grayish-white. The fin whale's blow is tall and columnar in shape.

The dorsal fin is situated far back on the body and is tall and steeply angled. A ridge runs behind the dorsal fin. The coloration and size of the chevron on the whale’s head is individually distinctive, similar to a human’s fingerprint. This and the shape and size of the dorsal fin allow researchers to identify and track individual whales.

Image of Range of the Fin whale off New Jersey's coast.Zoom+ Range of the Fin whale off New Jersey's coast.

Distribution and Habitat

Fin whales live within all of the major oceans of the world, primarily in temperate and polar waters. They are typically seen within deep, offshore waters, but they are often encountered within New Jersey’s coastal waters. Their migration patterns are poorly understood compared to some whale species, such as the humpback whale (Megaptera novaeangliae). It appears that fin whales may follow a similar migration as humpbacks within the western North Atlantic Ocean, feeding during spring, summer, and fall in northern latitudes and then spending the winter in the West Indies.

Summer feeding habitat is within cold waters where prey is abundant. Winter breeding and calving habitat is poorly understood for this species. Similar to humpback whales, it may be within warm subtropical or tropical waters. Their prey is largely absent from these waters which would require fin whales to go without any food during the months spent at the breeding grounds.


Fin whales primarily feed on tiny crustaceans known as krill as well as small schooling fish such as herring, capelin, and sand lance. They feed by filter feeding with their mouthful of baleen. They do so by taking a large mouthful of both prey and water, closing their mouth, and then pushing the water out of their mouth using their enormous tongue. The prey items are then left within the mouth, trapped by the strips of baleen, and ready to be swallowed.

Fin whales may often be seen feeding within groups of 2-7 individuals. In the North Atlantic Ocean, they will also be seen feeding near other species of whale, such as the humpback, and dolphins.

Life Cycle

During the summer, fin whales will spend most of their time feeding and building-up fat in the cold waters of the North Atlantic. These fat stores will be necessary for the long migration to their winter breeding and calving grounds. The winter breeding grounds are most likely located in warmer subtropical or tropical waters, where no feeding will take place during the entire time they are there.

Little is known about the fin whale mating. Like other baleen whales, it is likely that long-term bonds are rare. Males are sexually mature at 6-10 years of age while females are at 7-12 years of age. Fin whale pregnancy lasts for 11-12 months. New born calves are approximately 18 feet long, weigh up to 2 tons, and grow quickly feeding on the milk of their mother. Males play no role in raising their young.

Fin whales are known as the greyhounds of the sea because they are very fast swimmers. Their only predator, aside from humans, is the killer whale (Orchinus orca). Fin whales may live to an age of 80-90 years.

Current Threats, Status, and Conservation

All of the large whale species have been at risk of extinction due to a long history of whaling. The principal attraction of whaling was the whale's blubber, which yielded oil ideal for lamp oil and, much later, in the production of margarine. Baleen was also of value. Whalebones were also used in the manufacture of glue, gelatin and manure. Besides being eaten by humans, the meat has also been used in dog food and, when dried and crushed, cattle feed.

Commercial whaling of fin whales ended in 1987 due to the decline of the species. It was listed by the federal government as endangered in 1970 and, as a result of that federal status, was automatically added to the New Jersey endangered species list following enactment of the New Jersey Endangered and Nongame Species Conservation Act in 1973. Fin whales are provided with additional protection with the Marine Mammal Protection Act of 1972.

Despite the ban on hunting, fin whales face a number of threats, all of which are caused by humans. These threats include entanglement in fishing gear, collisions with ships, harassment by whale watchers, habitat impacts, and proposals to allow for a commercial hunt once again.

One of the greatest threats to fin whales is entanglement in fishing gear. Fin whales may become wrapped-up in nets and/or fishing line around their tail, mouth, or other body part. Discarded nets and lines may float at sea for decades or become snagged on rocks or debris at the ocean bottom. Once entangled in fishing gear, the whale may face an agonizing death, pulling the gear along while it swims for many days, months, or even years, as the gear slowly cuts through their body and causes swimming to become more difficult. Scars on whale bodies are often an indication of a previous entanglement from which they escaped.

Collisions with ships are an increasing threat to fin whales. The increasing number of large and fast ships, especially near busy ports such as the port of New York/New Jersey, results in whales and ships being in close proximity more often. Unfortunately, whales do not always know or have time to react to the approach of large ships and they get hit, usually resulting in their death.

Whale watching vessels may stress or accidently strike whales. There are whale watching guidelines in place which restrict ships’ approach distance and direction to whales and it is against the law to violate these. Unfortunately, some countries throughout the world do not impose such regulations on whale watching, resulting in the whales being harassed by too many vessels at too short a distance from the whale.

Negative impacts to whale habitat may take the form of development, pollution, noise, overfishing, and climate change. Shipping channels, aquaculture, offshore energy development, and recreational use of marine areas may destroy whale habitat or displace whales which would normally use the area. Oil spills and other chemical pollutants are also a threat to whales and the prey which they feed on.

Another form of pollution is noise pollution. Whales’ primary means of communication, navigation, locating food, locating mates, and avoiding predators and other threats is through their sense of hearing, which is much more highly developed than that of humans. Noise pollution created by ship traffic or offshore construction may negatively impact whales by disrupting otherwise normal behaviors associated with migration, feeding, alluding predators, rest, breeding, etc. Any changes to these behaviors may decrease survival, simply by increasing efforts directed at avoidance of the noise and the perceived threat. Active sonar, such as that used by the Navy, also threatens marine mammals by disrupting navigation, foraging and communication abilities. There have been instances of whale stranding and death caused by acoustic trauma. This may be due to a fatal injury within the structure of the ear, or may result from the distressed animal surfacing too rapidly and developing nitrogen bubbles within their blood (decompression sickness). In addition to the direct threat posed by active sonar, it may indirectly harm marine species by causing changes in behavior.

Overfishing of the small fish which fin whales feed upon is another potential cause for concern as well as the potential impacts of global climate change. This issue may be the greatest long-term threat to the marine habitat and its species. Climate change may significantly alter the chemical balance of the seas, off-shore currents, and plankton distribution and abundance, thereby affecting migration routes of marine species and impacting the entire food web.

It is unknown whether fin whales are recovering throughout much of their range. Ship strikes and entanglements may be slowing their recovery. Within the western North Atlantic Ocean, the best available estimate of their population is approximately 1,678 individuals. There is still no commercial hunt for fin whales although several countries are interested in hunting them commercially again. Several countries currently allow hunting for this species. In Greenland, hunting is allowed for native peoples, subject to catch limits. Japan also hunts the species, claiming it does so for “scientific” purposes. The population today, however, remains endangered and such hunts may be setting back decades of recovery.

Although fin whales are large animals, we don’t currently know a great deal about their habitat use off the coast of New Jersey. It is unknown whether they may be using New Jersey waters as a migratory pathway between their summer feeding grounds in the north and their winter breeding grounds in the south. Surveys are currently being conducted off the New Jersey coastline in order to determine where whales are located, how many individuals are there, and during what time of year. Based on these findings, further knowledge regarding their habitat use in New Jersey waters may be gained and attention may then focus on protecting important habitats.

Text derived from the book, Endangered and Threatened Wildlife of New Jersey. 2003. Originally edited by Bruce E. Beans and Larry Niles. Edited and updated Michael J. Davenport in 2010.

Scientific Classification

Kingdom: Animalia
    Phylum: Chordata
       Class: Mammalia
          Order: Cetecea
             Family: Balaenopteridae
                Genus: Balaenoptera
                   Species: B. physalus

Find Related Info: Endangered, Mammals

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