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Balaenoptera edeniBryde's whale

By Jessica O'Grady

Geographic Range

Bryde’s whales (Balaenoptera edeni) can be found in the Pacific, Indian and Atlantic oceans, but they are most commonly found in tropical and sub-tropical regions. These whales have not been found beyond 40° in either hemisphere. Due to their warm water preference, they have been observed migrating towards the equator in the winter. Some small populations are known to be sedentary, including a small population of about 12 individuals along the coast of California. Molecular evidence has suggested that the smaller coastal whales may be a different species than the larger whales that live in deeper waters. ("Bryde's Whale", 2012; Allen, et al., 2011; Jefferson, et al., 2008; Shirihai, 2006)

Habitat

Bryde's whales live in warm oceanic waters, with temperatures ranging from 15 to 20 degrees C. They are coastal and pelagic creatures that usually follow their food sources. While pursuing prey, they have been observed diving as deep as 300 m. (Allen, et al., 2011; Jefferson, et al., 2008; Shirihai, 2006)

  • Range depth
    300 (high) m
    984.25 (high) ft

Physical Description

Bryde's whales are small rorquals, whales of family Balaenopteridae, whose males range in size from 12 to 13 m, while females are slightly larger, ranging from 13 to 14 m. Both sexes weigh 13,600 to 15,000 kg. Their body is a dark smokey grey above, which then diffuses into a white below. Circular scars from lampreys and cookiecutter sharks have been spotted on the more migratory individuals. With a V-shaped rostrum, their head occupies 25% of their body and has 3 ridges on the top that run from the tip of their snout to the front of their blowhole. Underneath, 54 to 56 throat grooves lie between each flipper and extend beyond their navel. Inside their mouth, 285 to 350 slate gray coarse baleen plates are found on each side, the longest plate is 40 cm. Bryde's whales have 54 to 55 vertebrae, along with 13 to 14 broad, thin ribs; the first rib is double-headed. Their dorsal fin is slightly curved or hooked, while the other fins are short, narrow, and pointed. Their flukes are wide and occupy 24% of the body length. Older research had recognized a pygmy version of Bryde's whales, but since 2003 they have been classified as their own distinct species, Omura's whales. Physically, juveniles have similar characteristics. (Allen, et al., 2011; Jefferson, et al., 2008; Shirihai, 2006)

  • Sexual Dimorphism
  • female larger
  • Range mass
    13,600 to 15,000 kg
    to lb
  • Range length
    12 to 14 m
    39.37 to 45.93 ft

Reproduction

Research is lacking on the mating system of Bryde's whales. It is assumed that their breeding behavior is comparable to other related cetaceans.

Bryde's whales reach sexual maturity when they are 10 to 12 m long and 10 to 13 years old. The sedentary, inshore whales conceive throughout the year, while the more pelagic, offshore whales breed more often in the fall months. Much like other whales, their ovulation is spontaneous. Gestation lasts for 11 to 12 months, the first 4 months of pregnancy involves slow fetal development, while the remaining development is considerably faster. At birth, calves have an average length of 3.4 meters and weigh approximately 900 kg. Females have one calf per breeding season, and nurse the calf for 6 months. Females have a 6-month recovery period after the calf reaches maturity at 6 months of age, as evidenced by births occurring every other year. (Allen, et al., 2011; Jefferson, et al., 2008; Kerosky, et al., 2012; Shirihai, 2006; Tershy, 1992; Wiseman, et al., 2011)

  • Breeding interval
    Bryde's whales breed every other year.
  • Breeding season
    These whales can breed at any time in the year.
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    11 to 12 months
  • Average weaning age
    6 months
  • Average time to independence
    6 months
  • Range age at sexual or reproductive maturity (female)
    10 to 13 years
  • Range age at sexual or reproductive maturity (male)
    10 to 13 years

Females nurse their calves for 6 months, with no paternal influence. At the end of the weaning period, the mother leaves the calf to fend for itself. (Allen, et al., 2011; Jefferson, et al., 2008; Shirihai, 2006; Tershy, 1992)

Lifespan/Longevity

In the wild, Bryde's whales can live 50 to 70 years, the oldest recorded individual was 72 years old; nothing is known about their lifespan in captivity. (Allen, et al., 2011)

  • Range lifespan
    Status: wild
    72 (high) years
  • Typical lifespan
    Status: wild
    50 to 70 hours

Behavior

Bryde's whales are mostly solitary. Those living near the shore may have feeding groups of 15 or less, while those living off-shore may have groups of up to 30. When they travel, 93% of Bryde's whales are solitary, a much greater percentage than the closely-related sei whales. However, Bryde's whales feed with many other whale species, interacting inter- and intra-specifically without aggression while feeding. Although it is uncommon for these whales to produce a visible blow, when they do, it is 3 to 4 m tall and narrow. Their dives usually last 5 to 15 minutes, with a maximum of 20 minutes. Bryde's whales most commonly swim at 1.6 to 6.4 km/h, but they have been recorded to reach 19 to 24 km/h. ("Bryde's Whale", 2012; Allen, et al., 2011; Jefferson, et al., 2008; Kerosky, et al., 2012; Shirihai, 2006; Tershy, 1992; Wiseman, et al., 2011)

Home Range

Movements within their primary, or home range, depend on the presence of food rather than breeding. Bryde's whales do not defend a territory. (Kerosky, et al., 2012; Oleson, et al., 2003; Tershy, 1992; Wiseman, et al., 2011)

Communication and Perception

Bryde's whales have been recorded emitting short, but loud, low-frequency moans. Most of the sounds they produce include two types of calls emitted simultaneously. They can repeat these calls every 1 to 3 minutes, and many are produced while the whales are moving. Whales call back and forth, and the type of calls differ with the size of the group. Baleen whales, unlike toothed whales, are not known to echolocate, but researchers have found fat pockets in the ears of baleen whales that are known to help toothed whales echolocate. Although they likely have no sense of smell, their vision and hearing appear to be similar to that of other cetaceans. (Allen, et al., 2011; Heimlich, et al., 2005; Jefferson, et al., 2008; Yamato, et al., 2012)

Food Habits

Bryde's whales are unique among other whales with their generalist diet, which enables them to stay year-round in warm waters where they can always find food. As baleen filter-feeders, they use multiple strategies for feeding, including bubble nets, skimming, and lunging. Although there is no evidence of communication while feeding, multiple whales are usually found in the same feeding location. Bryde's whales have also been seen cleaning up after other predators by ingesting the leftovers. The inshore groups prefer fish, specifically anchovies, sardines, mackerels, and herring, while the offshore groups eat copepods and krill of genus Euphausia. They also ingest cuttlefish, squid, and octopi. Each whale generally eats about 660 kg a day, which equates to about 4% of their body weight. (Alves, et al., 2010; Murase, et al., 2007; Tershy, 1992)

  • Animal Foods
  • fish
  • mollusks
  • aquatic crustaceans
  • other marine invertebrates
  • zooplankton

Predation

Researchers have witnessed predation by killer whales and shark species. When Bryde's whales are approached or pursued by a predator, they try to quickly swim away. (Allen, et al., 2011; Ford and Reeves, 2008; Jefferson, et al., 2008; Shirihai, 2006)

Ecosystem Roles

Due to presumed impacts of intense whaling efforts, we do not know the true ecological impact of these large whales. Bryde's whales host several parasitic species including parasitic worms, commonly called helminths. Other species found on these large whales are sea lice, copepods, amphipods, barnacles, and sea lampreys. Unlike the other species, sea lampreys can cause death, due to organ failure caused by infections or blood loss. (Magalhães Pinto, et al., 2004; Priddle and Wheeler, 1998; Ólafsdóttir and Shinn, 2013)

Commensal/Parasitic Species

Economic Importance for Humans: Positive

Although whaling is illegal in many parts of the world, there are still countries that have not adopted any laws concerning this practice. The International Whaling Commission was started in 1986 to help eliminate the hunting and killing of whales for their meat, oil, and bones. Common minke whales are the primary hunted species, but Bryde's whales look very similar and often are caught. In the western North Pacific, it is estimated that from 1911 to 1987, 20,000 whales were caught annually, while in South Africa an estimated 2,000 whales were caught from 1911 to 1967. (Reilly, et al., 2013)

  • Positive Impacts
  • food
  • body parts are source of valuable material

Economic Importance for Humans: Negative

There are no known adverse effects of Bryde's whales on humans.

Conservation Status

Due to the lack of research on abundance and distribution, Bryde's whales have been named "Data Deficient" on the IUCN Red list. According to CITES, Bryde's whales are classified as Appendix I, the most endangered species, but applications have been put in to move them to Appendix II, animals that are not threatened now but may become so if they are not watched closely. Bryde's whales are protected under the Marine Mammal Protection Act (MMPA), which prohibits the removal of marine mammals from U.S. waters and their importation into the U.S. Real and perceived threats to this species include whaling (legal and illegal), run-ins with ships, and the yet-unknown effects of human-caused noises (including sonar), which have caused the beachings and deaths of whales and other cetaceans. Whaling harvests are sometimes hard to calculate because Bryde's whales are often grouped with similar-looking species. However, reports indicate that an active whaling country, Japan, lied about its Bryde's whale harvest to remain under the catch limits. Specifically, a 1981 to 1987 harvest report from Japan indicated that 2,659 whales were caught, when they actually harvested over 4,000. Therefore, despite international laws and treaties, this species may still be at risk from illegal over-harvesting. ("Bryde's Whale", 2012; Reilly, et al., 2013)

Contributors

Jessica O'Grady (author), Radford University, Karen Powers (editor), Radford University, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

Glossary

Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

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Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

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Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

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Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

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Neotropical

living in the southern part of the New World. In other words, Central and South America.

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Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

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acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

choruses

to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species

coastal

the nearshore aquatic habitats near a coast, or shoreline.

cosmopolitan

having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

filter-feeding

a method of feeding where small food particles are filtered from the surrounding water by various mechanisms. Used mainly by aquatic invertebrates, especially plankton, but also by baleen whales.

food

A substance that provides both nutrients and energy to a living thing.

migratory

makes seasonal movements between breeding and wintering grounds

mimicry

imitates a communication signal or appearance of another kind of organism

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

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pelagic

An aquatic biome consisting of the open ocean, far from land, does not include sea bottom (benthic zone).

piscivore

an animal that mainly eats fish

planktivore

an animal that mainly eats plankton

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

ultrasound

uses sound above the range of human hearing for either navigation or communication or both

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

year-round breeding

breeding takes place throughout the year

young precocial

young are relatively well-developed when born

zooplankton

animal constituent of plankton; mainly small crustaceans and fish larvae. (Compare to phytoplankton.)

References

2012. "Bryde's Whale" (On-line). NOAA Fisheries. Accessed November 13, 2013 at http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/brydeswhale.htm.

New Zealand Department of Conservation. Bryde's whales (Balaenoptera cf. brydei Olsen 1913) in the Hauraki Gulf and northeastern New Zealand waters. 1173-2946. New Zealand: Science &Technical Publishing. 2007.

NOAA. U.S Pacific Marine Mammal Stock Assessments: 2000. NOAA-TM-NMFS-SWFSC-300. United States: United States Government. 2000.

Allen, S., J. Mortenson, S. Webb. 2011. Field Guide to Marine Mammals of the Pacific Coast. California, US: University of California Press.

Alves, F., A. Dinis, I. Cascao, L. Freitas. 2010. Bryde's whale (Balaenoptera brydei) stable associations and dive profiles: New insights into foraging behavior. Marine Mammal Science, 26/1: 202-212.

Corkeron, P. 2009. Reconsidering the science of scientific whaling. Marine Ecology Progress Series, 375: 305-309.

Ford, J., R. Reeves. 2008. Fight or Flight: antipredator strategies of baleen whales. Mammal Review, 38: 50-86.

Heimlich, S., D. Mellinger, S. Nieukirk. 2005. Types, distribution, and seasonal occurrence of sounds attributed to Bryde's whales (Balaenoptera edeni) recorded in the eastern tropical Pacific, 1999-2001. Journal of the Acoustical Society of America, 118/3: 1830-1837.

Jefferson, T., M. Webber, R. Pitman. 2008. Marine Mammals of the World: a Comprehensive Guide to their Identification. London, England: Elsevier Publications.

Kerosky, S., A. Sirovic, L. Roche, S. Baumann-Pickering, S. Wiggins, J. Hildebrand. 2012. Bryde's whale seasonal range expansion and increasing in the Southern California Bight from 2000 to 2010. Deep-Sea Research I, 65: 125-132.

Magalhães Pinto, R., L. Muniz-Pereira, V. Alves, S. Siciliano. 2004. First report of a helminth infection for Bryde's whale, Balaenoptera edeni Anderson, 1878. Latin American Journal of Aquatic Mammals, 3/2: 167-170.

Murase, H., T. Tamura, H. Kiwada, Y. Fujise, H. Watanabe, H. Ohizumi, S. Yonezaki, H. Okamura, S. Kawahara. 2007. Prey selection of common minke (Balaenoptera actorostrata) and Bryde's (Balaenoptera edeni) whales in the western North Pacific in 2000 and 2001. Fisheries Oceanography, 16/2: 186-201.

Oleson, E., J. Barlow, J. Gordon, S. Rankin, J. Hildebrand. 2003. Low frequency calls of Bryde's whales. Marine Mammal Science, 19/2: 407-419.

Priddle, D., R. Wheeler. 1998. Hematology and blood chemistry of a Bryde's whale, Balaenoptera edeni, entrapped in the manning river New South Wales, Australia. Marine Mammal Science, 14/1: 72-81.

Reilly, S., J. Bannister, P. Best, M. Brown, R. Brownell, D. Butterworth, P. Clapham, J. Cooke, G. Donovan, J. Urbán, A. Zerbini. 2013. "Balaenoptera edeni" (On-line). IUCN Redlist. Accessed November 10, 2013 at http://www.iucnredlist.org/details/2476/0.

Salvadeo, C., S. Flores-Ramirez, A. Gomez-Gallardo, C. MacLeod, D. Lluch-Belda, S. Jaume-Schinkel, J. Urban. 2011. Bryde's whale (Balaenoptera brydei) in the southwestern Gulf of California: Relationship with ENSO variability and prey availability. Ciencias Marinas, 37/2: 215-225.

Shirihai, H. 2006. Whales, Dolphins, and Other Marine Mammals of the World. Princeton, NJ: Princeton University Press.

Siciliano, S., M. Cesar de Oliveira Santos, A. Vicente, F. Alvarenga, E. Zampirolli, J. Brito, A. Azevedo, J. Pizzorno. 2004. Strandings and feeding records of Bryde's whales (Balaenoptera edeni) in south-eastern Brazil. Journal of the Marine Biological Association of the United Kingdom, 84: 857-859.

Smultea, M., A. Douglas, C. Bacon, T. Jefferson, L. Mazzuca. 2012. Bryde's whale (Balaenoptera brydei/ edeni) sightings in the Southern California Blight. Aquatic Mammals, 38/1: 92-97.

Tershy, B. 1992. Body size, diet, habitat use, and social behavior of Balaenoptera whales in the gulf of California. Journal of Mammalogy, 73/3: 477-486.

Wiseman, N., S. Parsons, K. Stockin, S. Baker. 2011. Seasonal occurrence and distribution of Bryde's whales in the Hauraki Gulf, New Zealand. Marine Mammal Science, 27/4: 253-267.

Yamato, M., D. Ketten, J. Arruda, S. Cramer, K. Moore. 2012. The auditory anatomy of the minke whale (Balaenoptera acutorostrata): A potential fatty sound reception pathway in a baleen whale. The Anatomical Record, 295: 991-998.

Ólafsdóttir, D., A. Shinn. 2013. Epibiotic macrofauna on common minke whales, Balaenoptra acutorostrata Lacépéde, 1804, in Icelandic waters. Parasites & Vectors, 6/1: 105.

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