Fin Whale

## Description

The fin whale (Balaenoptera physalus ), also known as finback whale or common rorqual and formerly known as herring whale or razorback whale, is a cetacean belonging to the parvorder of baleen whales. It is the second-longest species of cetacean on Earth after the blue whale. The largest reportedly grow to 27.3 m (89.6 ft) long with a maximum confirmed length of 25.9 m (85 ft), a maximum recorded weight of nearly 74 tonnes (73 long tons; 82 short tons), and a maximum estimated weight of around 114 tonnes (112 long tons; 126 short tons). American naturalist Roy Chapman Andrews called the fin whale "the greyhound of the sea... for its beautiful, slender body is built like a racing yacht and the animal can surpass the speed of the fastest ocean steamship."

The fin whale's body is long and slender, coloured brownish-grey with a paler underside. At least two recognized subspecies exist, in the North Atlantic and the Southern Hemisphere. It is found in all the major oceans, from polar to tropical waters. It is absent only from waters close to the pack ice at the poles and relatively small areas of water away from the open ocean. The highest population density occurs in temperate and cool waters. Its food consists of small schooling fish, squid, and crustaceans including copepods and krill.

Like all other large whales, the fin whale was heavily hunted during the 20th century. As a result, it is an endangered species. Over 725,000 fin whales were reportedly taken from the Southern Hemisphere between 1905 and 1976; as of 1997 only 38,000 survived. Recovery of the overall population size of southern subspecies is predicted to be at less than 50% of its pre-whaling state by 2100 due to heavier impacts of whaling and slower recovery rates.

The International Whaling Commission (IWC) issued a moratorium on commercial hunting of this whale, although Iceland and Japan have resumed hunting. The species is also hunted by Greenlanders under the IWC's Aboriginal Subsistence Whaling provisions. Global population estimates range from less than 100,000 to roughly 119,000.

## Appearance

Fin whales are the fastest amongst the cetaceans and have been seen to breach completely out of the water. It is gray on the upper surface and white on the underside. Patterns on its jaw are asymmetrical: white on the right and dark on the left side, with large numbers of grooves extending along the throat to its naval. Its prominent dorsal fin has a strong curve. Males and females are very similar in appearance, with females slightly longer than males. Their baleen plates are gray to bluish in color, with white fringes. They have two blowholes, with a single, longitudinal ridge extending from the tip of their snout to where their blowholes begin.

## Distribution

This species is distributed throughout the globe, though it is rarely seen in tropical or icy polar seas. It is found in the Pacific, Indian, Atlantic and Arctic Oceans. It has two subspecies: the northern fin whale, which inhabits the North Atlantic; and the southern fin whale, which lives in the Southern Ocean. It is the only rorqual found commonly in the Mediterranean. They inhabit the polar and temperate zones of major and open seas as well as, less commonly, the tropical oceans. They more commonly live in shelf and coastal waters, never in water that is less than a depth of 200 meters.

## Behavior

Fin whales are one of the most sociable of whale species, often congregating in family groups of 6 to 10 members. Sometimes they gather in groups of almost 250 individuals during migration periods or near feeding grounds. This species is highly migratory: they usually live in colder feeding water during spring and early summer, and in autumn and winter they go back to warmer waters to breed. A fin whale is a filter feeder and hunts by swimming with its mouth open towards its prey, taking in large amounts of water as well as food. Fin whales communicate with loud low-pitched sounds. The purpose of these noises is unknown, but they may play a part in helping whales to locate each other or attract a mate.

## Diet

Fin whales mainly eat plankton-sized animals including fish, crustaceans, and squid.

## Reproduction

Fin whales are regarded as monogamous, often being seen during the mating season in pairs. Mating takes place in the northern hemisphere between November and January, and the southern hemisphere between June to September. After an 11-11.5-month gestation period, one calf is born. A calf is precocial at birth, and is able to swim as soon as it is born. A mother nurses her baby for 6 to 8 months. The calf is about 14 meters long when it is weaned, whereupon it travels to a polar feeding area with its mother, and learns there to feed independently of its mother. Males are sexually mature at 6 - 10 years old. Females give birth to a calf every two years once they reach sexual maturity between 3 to 12 years old.

## Population

### Population threats

Fin whales, like other large whales, are threatened by changes to the environment, including habitat loss, climate change and toxins. At present, fin whales are threatened by manmade injuries, the most serious being collisions with boats. They are also threatened by commercial whaling. The majority of whale meat is bought on the Japanese market.

### Population number

There are very rough estimates for specific regions: North Atlantic - 53,000 whales; Mediterranean Sea - fewer than 10,000 whales; North Pacific – 17,000 whales; Southern Hemisphere - 38,185 whales. Currently the Fin whale is classified as Endangered (EN).

### Ecological niche

Fin whales have a place at the top in the food chain and an important role as regards the marine environment's overall health, consuming vast amounts of plankton as well as other prey items.

## Fun Facts for Kids

Fin whales can expand their mouths and their throats while feeding due to the 100 or so pleats that go from the end of their bodies right to their mouths. The pleats enable the mouth cavity during feeding to engulf water, Fin whales being filter feeders, with 350 to 400 baleen plates that they use to catch very small up to medium-sized life that is suspended in the sea.

Fin whales can dive as deep as 230 meters and stay submerged for around 15 minutes. A fin whale's blow reaches six meters height and is shaped like a slim cone.

Fin whales like to leap completely above the surface of the water as they come up to breathe. Doing this enables them to dive approximately 800 feet back down into the water.

Since a calf is not able to suckle, the mother sprays her milk into the baby's mouth. Feeding occurs throughout the day at intervals of 8 to 10 minutes.

The Fin whale is the second largest animal in the world, the blue whale being the largest.

The shape of their backs and their small pointed dorsal fins have given these whales another name, which is razorback.