Fin whale (Balaenoptera physalus) COSEWIC assessment and status report: chapter 2

• Previous page
• Table of contents
• Next page

COSEWIC Executive Summary

Species information

Southern and northern hemisphere fin whales are considered subspecies based on slight morphological differences and suspected reproductive isolation: B. p. physalus in the northern hemisphere and B. p. quoyi in the southern hemisphere. Common English names include finback and finner. French common names include rorqual commun, baleine à nageoires and baleinoptère commune.

The fin whale is the second largest member of the Balaenopteridae family, after the blue whale (B. musculus), and is characterized by its fast swimming speed and streamlined body. The most distinguishing feature is the asymmetrical pigmentation on the lower jaw – dark on the left and light on the right. This asymmetry continues through a portion of the baleen plates.

In Canadian waters, fin whales are most likely to be confused with blue or sei whales. Considerable overlap exists with sei whales with regard to body size, colouration and dorsal fin shape.

Distribution

Fin whales are found in all oceans of the world and generally make seasonal migrations from low-latitude wintering areas to high-latitude summer feeding grounds. Winter distribution appears to be less concentrated. The locations of the wintering grounds are poorly known. Summer concentrations in the western North Atlantic are in the Gulf of St. Lawrence, on the Scotian Shelf, in the Bay of Fundy, in the nearshore and offshore waters of Newfoundland, and off Labrador. In the eastern North Pacific, fin whales are assumed to migrate through Canadian waters, although significant numbers are observed feeding in British Columbia waters throughout the summer.

Habitat

Fin whales are associated with low surface temperatures and oceanic fronts during summer months. In the western North Atlantic, they are found from close inshore to well beyond the shelf break. In the Pacific, only 17% of the commercial catch of fin whales by shore whaling stations was on the continental shelf. The defining characteristic of fin whale feeding habitat is likely high concentrations of prey, particularly euphausiids and small schooling fish. Characteristics of preferred breeding grounds are unknown.

Biology

Fin whales reach sexual maturity at 5-15 years of age, and physical maturity at about 25. The average length at sexual maturation is about 17 m. Adult animals range from 20-27 m, with animals in the northern hemisphere somewhat shorter (mean length of 24 m), and lighter (40-50 tonnes) than those in the southern hemisphere. Conception and calving are believed to occur in the winter at low latitudes. After a gestation of 11-12 months, calves are born at an average length of 6 m, and are weaned after about 6 months, making the breeding cycle about 2 years long. There is little information on mortality rates.

A staged seasonal migration, with pregnant females moving into high-latitude feeding areas in advance of adult males and resting females, has been reported, but in comparison to the migration pattern of humpback whales, for example, that of fin whales appears diffuse. Not all individuals migrate every year; some spend extended periods on the feeding grounds.

Fin whales have a fairly diverse diet. In the North Pacific, they eat mainly euphausiids, followed by copepods, with some fish and squid. In the North Atlantic, they eat euphausiids, capelin and herring, with considerable variation by location and time of year.

Population sizes and trends

Pre-commercial whaling estimates of fin whale numbers in the North Pacific are in the order of 40,000 – 45,000. By the time commercial whaling there ended, perhaps 13,000 – 19,000 remained, most of them in the eastern half of the basin. Whaling stations in British Columbia took more than 7,600 fin whales. The most recent minimum population estimate for the California/Oregon/Washington region (early 2000s) is about 2,500, and about 5,000 were estimated in the Bering Sea in 1999.

Pre-commercial whaling estimates for the North Atlantic population are also in the order of 30,000 – 50,000. The best available recent estimates for parts of the western North Atlantic are 2,814 (CV=0.21) between Georges Bank and the mouth of the Gulf of St. Lawrence in 1999 and about 380 in the Gulf of St. Lawrence in the mid-1990s.

No good evidence of trend is available for either population.

Limiting factors and threats

The most significant direct threats are ship strikes and entanglement in fishing gear. Fin whales may also be negatively affected by ecological interactions with fisheries but these have not been clearly specified or validated. Human-generated underwater noise similarly may degrade fin whale habitat and impair communication but details are uncertain. The ways and degrees to which fin whale populations are being affected by chemical pollution and climate change are also unknown.

Special significance of the species

The fin whale is the second largest animal on Earth. It was a pillar of the modern whaling industry. Nowadays fin whales are economically important to whale-watching enterprises in Atlantic Canada, particularly in the lower Bay of Fundy and the St. Lawrence Estuary.

Existing protection or other status designations

The fin whale is listed by IUCN as “endangered” on the basis of large and rapid population declines caused by 20^th century whaling. CITES lists the species in Appendix 1, meaning that products are prohibited in commercial trade. The species is listed as “endangered” under the United States Endangered Species Act. The International Whaling Commission’s “moratorium” on commercial whaling remains in effect. Fin whales are hunted under an IWC-sanctioned “subsistence” quota in Greenland.

In Canada, federal Marine Mammal Regulations (Fisheries Act) prohibit disturbance of marine mammals, while three federal agencies (Fisheries and Oceans Canada, Parks Canada, and Environment Canada) have separate enabling legislation to designate protected areas in the marine environment.

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal agencies (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government members and the co-chairs of the species specialist and the Aboriginal Traditional Knowledge subcommittees. The Committee meets to consider status reports on candidate species. 

Definitions (November 2004)

Wildlife Species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)^Footnotea

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)^Footnoteb

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)^Footnotec

A wildlife species for which there is inadequate information to make a direct, or indirect, assessment of its risk of extinction.