The fin whale, Balaenoptera physalus, is a large baleen whale, recognized as the second-longest animal on Earth. These elongated marine mammals are characterized by their distinctive V-shaped head and a prominent dorsal fin located far back on their body. Fin whales are a widespread marine mammal, found across various oceanic environments globally.
Global Distribution of Fin Whales
Fin whales are truly cosmopolitan, inhabiting all major ocean basins from polar to tropical waters. Their highest population densities occur in temperate and cool waters of both the Northern and Southern Hemispheres. While found globally, populations in the North Atlantic and North Pacific are largely distinct from those in the Southern Hemisphere, as their migration schedules are six months out of phase, preventing intermingling.
In the North Atlantic, fin whales are found from Baffin Bay and the Irminger Sea south to the Gulf of Mexico and the Greater Antilles, as well as across to Iceland, the Azores, and the Iberian Peninsula. The Mediterranean Sea also hosts a significant resident fin whale population. Pacific populations extend from central Baja California northward to Japan and the Chukchi Sea, with high densities in areas like the northern Gulf of Alaska and southeastern Bering Sea. Southern Hemisphere fin whales inhabit the Antarctic and Indian Ocean, reaching coasts of New Zealand, Peru, and South Africa, particularly during the austral summer months.
Preferred Habitats and Environmental Factors
Fin whales consistently favor areas characterized by high marine productivity, which are regions where ocean currents, upwelling, and seasonal changes create conditions for abundant prey. They generally prefer open ocean, deep offshore waters, and the edges of continental shelves, typically found in depths ranging from 400 to 2,000 meters. These shelf edges, along with submarine canyons and seamounts, are significant because they channel nutrients, supporting rich marine ecosystems and creating feeding hotspots for their prey.
The presence of cold, productive waters is also a factor, as these environments are rich in the fin whale’s primary food sources. Their diet primarily consists of small schooling fish like herring, capelin, and sand lance, along with krill and copepods. This preference for nutrient-rich waters directly correlates with the availability of their prey, which aggregates in dense swarms in these specific habitats.
Seasonal Movements and Migration
Fin whales are known for their extensive seasonal migrations, typically moving between high-latitude feeding grounds in the summer and lower-latitude breeding grounds during winter months. While the precise migration patterns can vary among populations, the general trend involves a poleward movement for feeding and an equatorial movement for breeding.
In the North Atlantic, fin whales travel from summer feeding areas like the Gulf of Maine, Labrador Sea, and Norwegian waters south towards the Caribbean Sea, Gulf of Mexico, or Mediterranean Sea for breeding. Similarly, Pacific populations feed in Alaskan and Canadian waters before heading to warmer Pacific regions, such as off the coast of Baja California. Southern Hemisphere fin whales migrate between Antarctic waters in summer and warmer Southern Ocean areas for breeding and calving. Though their breeding grounds are generally in temperate or tropical areas, their exact locations are less well-known compared to their feeding areas, as they tend to occur in the open ocean. Some populations, such as those in the Mediterranean and Gulf of California, exhibit more resident behavior and can be found year-round.