Bryde's Whale (Balaenoptera edeni)
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Photo: NOAA's Southeast Fisheries Science Center
Species: edeni - edeni, brydei, omurai
Omura's Whale (Balaenoptera omurai) - a "pygmy form" of the bryde's whale only recently described, in 2003, as Omura's whale
|Weight:||about 90,000 lbs (40,000 kg)|
|Length:||40-55 ft (13-16.5 m)|
|Appearance:||large yet sleek body that is dark gray with white , they have 3 ridges near their blow hole|
|Lifespan:||unknown, but sexually mature at 8-13 years|
|Diet:||plankton (like krill and copepods), crustaceans (like red crabs and shrimp), schooling fish (like anchovies, herring, mackerel, pilchards, and sardines)|
|Behavior:||usually sighted individually or in pairs|
Bryde's (pronounced "broodus") whales are members of the baleen whale family and are considered one of the "great whales" or rorquals. These rorquals can reach lengths of about 40-55 ft (13-16.5 m) and weigh up to about 90,000 lbs (40,000 kg). Males are usually slightly smaller than females.
The taxonomic status and relationships within the Bryde's whale species is very complex and poorly understood due to several genetically distinct species/subspecies/morphologies recognized, discussed, and debated in the scientific literature. Some scientists suggest that there may be up to 3 species (Bryde's whale Balaenoptera brydei, Bryde's/Eden's whale Balaenoptera edeni (Olsen, 1913), and Omura's whale Balaenoptera omurai (Wada, Oishi, and Yamada, 2003)) based on geographic distribution, inshore/offshore forms, and a pygmy form. For at least two of the species, the scientific name B. edeni is commonly used. The Bryde's whale's "pygmy form" (max. about 37.5-39 ft or 11.5-12 m in length) has only recently been described and is now known as Omura's whale.
Bryde's whales are large animals (considered medium-sized for balaenopterids) that have a sleek body that is dark gray in color and white underneath. They look similar in appearance to sei whales, but can be distinguished by three distinct prominent longitudinal ridges located on the animal's rostrum in front of the blowhole. Sei whales, like other rorquals, have a single median ridge on their rostrum. The little known Omura's whale, which is believed to occur in the western Pacific and southeast Asia, has been described as missing the characteristic rostrum ridges of typical Bryde's whales and having asymmetrical pigmentation on the head, similar to the appearance of fin whales. The head of Bryde's whales makes up about one quarter of the whale's entire body. These whales have an erect, "falcate" "dorsal" fin located far down the animals back and broad flukes. On each side of Bryde's whales mouths are 250-410 gray colored coarse baleen plates (generally less than 40 cm long). Between 40-70 ventral pleats are located on the animal's underside. Omura's whales' mouths contain 180-210 baleen plates on each side of their jaw and 80-90 ventral pleats on the throat to navel area.
When at the water surface, these animals can be sighted by a columnar or bushy blow that is about 10-13 ft (3-4 m) in height. Sometimes these blows or exhales occur underwater. Bryde's whales are often characterized by field biologists as displaying erratic and strange behavior compared to other baleen whales because they surface for irregularly spaced time intervals and can unexpectedly change directions.
These large baleen whales are usually sighted individually or in pairs, but there are reports of loose aggregations of up to twenty animals associated with feeding areas. These whales opportunistically feed on plankton (e.g., krill and copepods), and crustaceans (e.g. pelagic red crabs, shrimp) as well as schooling fish (e.g., anchovies, herring, mackerel, pilchards, and sardines). Bryde's whales use different methods to feed, including skimming the surface, lunging, and creating bubble nets. They regularly dive for about 5-15 minutes (max of 20 min) after 4-7 blows at the surface. Bryde's whales are capable of reaching depths up to 1,000 ft (300 m) during dives. When diving, these whales do not display their flukes. Bryde's whales commonly swim at 1-4 mph (2-7 km/hour), but are capable of reaching speeds up to 12-15 mph (20-25 km/hour). They sometimes generate short (0.4 seconds) powerful vocalizations that have low frequencies and sound like "moans."
Bryde's whales become sexually mature at 8-13 years of age and may mate year round. The peak of the breeding and calving season may occur in the autumn. Females breed every second year, with a usual gestation period of 11-12 months. Females give birth to a single calf that is about 11 ft (3.4 m) in length, that is nursed for about 6-12 months.
Bryde's Whale Range Map
(click for larger view PDF)
Bryde's whales prefer highly productive tropical, subtropical and warm temperate waters worldwide (61-72° F or 16-20° C). The smaller form of this species may prefer waters near the coast and continental shelf.
Bryde's whales likely have a cosmopolitan distribution and occur in tropical and warm temperate oceans (Atlantic, Indian, and Pacific) around the world. They can be found globally in all oceans from 40° South to 40° North. Some populations of Bryde's whales may migrate seasonally, moving towards higher latitudes during the summer and towards the equator during the winter. Other populations of Bryde's whales are residents and do not migrate; this is unique among baleen whales. The distribution of Omura's whales includes the nearshore and continental shelf waters of the southeast Asia, eastern Indian, and western Pacific Ocean.
Photo: Sophie Webb, NOAA's Southeast Fisheries Science Center, STAR 2006
For management purposes, Bryde's whales inhabiting U.S. waters have been divided into three stocks: the Eastern Tropical Pacific stock, Hawaiian stock, and Northern Gulf of Mexico stock. The estimated population of Bryde's whales in the eastern tropical Pacific is 11,000-13,000, in the Hawaiian Islands is 350-500, and in the northern Gulf of Mexico is 25-40. Also, there is an estimated population of 12 animals in the coastal waters of California, Oregon, and Washington. There may be up to 90,000-100,000 animals worldwide, with two-thirds occurring in the Northern Hemisphere. There are insufficient data to determine the population trends for this species.
- ship strikes
- underwater sounds and anthropogenic noise are an increasing concern for Bryde's whales, and all baleen whales, which use low-frequency sounds to communicate with one another
- whaling outside the U.S.
- As part of their scientific research whaling program, the Japanese continue to hunt this species
- Artisanal whalers have hunted and taken Bryde's whales off the coasts of Indonesia and the Philippines
The IUCN Red List of Threatened Species considers this species "Data Deficient" due to insufficient information on population status and trends. Omura's whale is not listed by the IUCN.
This species is protected under the Marine Mammal Protection Act of 1972, as amended.
|Petition to list the Gulf of Mexico DPS as endangered||n/a||09/2014|
|Stock Assessment Reports||n/a||various|
- NMFS National Marine Mammal Laboratory Baleen Whale Information
- American Cetacean Society: Sei and Bryde's Whale Fact Sheet
- Animal Diversity Web: Bryde's Whale Information
- Ocean Biogeographic Information System (OBIS-SEAMAP) Bryde's Whale Species Profile
- Jefferson, T. A, M. A. Webber, and R. L. Pitman. (2008). Marine Mammals of the World, A Comprehensive Guide to their Identification. Amsterdam, Elsevier. p.54-58.
- Reeves, R. R., P. A. Folkens, et al. (2002). Guide to Marine Mammals of the World. New York, Alfred A. Knopf. p.222-225.
- Shirihai, H. and B. Jarrett (2006). Whales, Dolphins and Other Marine Mammals of the World. Princeton, Princeton University Press. p.58-61.
Updated: September 30, 2014