There are no known negative impacts of Blainsville's beaked whales on humans.
There are no records of any predation of Blainville's beaked whales.
Blainville's beaked whales have long and narrow bodies, similar to the other species in the genus Mesoplodon. Their fusiform bodies are widest near the middle and taper at each end. They weigh 820 to 1,030 kg and have an estimated lengths of 4.5 to 4.6 m. The longest recorded length was a female with a length of 4.7 meters. At birth, they are roughly 2 m long and weigh around 60 kg.
Blainsville's beaked whales have a moderately flat melon, somewhat long beak, thick rostrum, a small falcate dorsal fin located roughly two-thirds down the back, and a pair of throat grooves found under the lower jaw. Their blowhole tends to be semi-circular with the open side aimed toward its head. Blainville's beaked whales are dark bluish gray color on the dorsal and lateral regions and lighter gray on the ventral side. They are very difficult to distinguish from other members of their genus because they are so similar in appearance.
Males have a heavily arched rear half of their lower jaw, unlike juveniles and females. Males also have large teeth that project out from the lower jaw and rise above the upper jaw. Single-stalked barnacles often bind to these exposed teeth in small clusters. Females and juveniles also have teeth, but they are not easily seen because they are beneath the tissue of the gum within the mouth. Males often have scars present on their bodies, which studies suggest result from competing with each other for access to females.
Average mass: 820-1,030 kg.
Average length: 4.5-4.6 m.
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 1.088e+06 g.
The lifespan of Blainville's beaked whales is unknown.
Average lifespan
Sex: female
Status: wild: 27.0 years.
Blainville's beaked whales seem to prefer warm temperates and tropical waters, avoiding the Arctic and Antarctic Oceans. They prefer water temperatures from 10°C to 32°C. Preferred depths range from 700 to 1000 meters, often alongside much deeper waters. They seem to favor areas that are topographically diverse. Along with temperature, depth, and topography, their habitat is dependent on the level of productivity in the water. Blainville's beaked whales were once thought to avoid coastal regions and shallow waters, however, recent studies suggest that they seem to be more pelagic than other species of beaked whales and are the most frequently spotted of all beaked whales near tropical islands.
Average depth: 700-1000 m.
Habitat Regions: temperate ; tropical
Blainville's beaked whales are thought to have the widest range of all species in their genus Mesoplodon. This cosmopolitan species occurs in every ocean with exception of the Arctic. Blainville's beaked whales prefer tropical and warm temperate waters, and their distribution may vary with the movements of warm-water currents. In the Western Atlantic, their range stretches from the Gulf of Mexico and the Caribbean Sea to Nova Scotia. A number of strandings have been reported from Florida to Nova Scotia, and also in Puerto Rico. In the eastern Atlantic, they have been recorded off the coasts of Spain, the Netherlands, Portugal, the United Kingdom, and the Canary Islands. The farthest north they have been recorded in the eastern Atlantic is Aberaeron, Wales. In the Pacific, Blainville's beaked whales range from California to Taiwan. Records of strandings and sightings in the Pacific include the Line Islands, the Philipines, the mainland coast of China, Japan, the Ryukyu Islands, Midway, the Cook Islands, the Solomon Islands, New Caledonia, and the Hawaiian Islands. There are few records of Blainville's beaked whales in the Indian Ocean, likely due to a low observation effort. They have been recorded in Seychelles, Nicobar Islands, and the Maldives. Strandings have also been reported on the island of Mauritius in the southwest Indian Ocean.
Biogeographic Regions: nearctic ; palearctic ; oriental ; ethiopian ; neotropical ; australian ; oceanic islands ; indian ocean; atlantic ocean ; pacific ocean ; mediterranean sea
Other Geographic Terms: cosmopolitan
Most of the information on the food habits of Blainville's beaked whales is collected from the stomach contents of stranded individuals. The primary prey is thought to be cephalopods (Cephalapoda), as they eat armhook squid (Gonatidae), glass squid (Cranchiidae), and cock-eyed squid (Histioteuthidae). However, they most likely consume a significant quantity of other fish and invertebrates.
Animal Foods: fish; mollusks; other marine invertebrates
Primary Diet: carnivore (Eats other marine invertebrates)
Blainsville's beaked whales prey on cephalopods, but are not known to be eaten by any other animals. Barnacles (Cirripedia) attach themselves to the tusk-like teeth of males.
Commensal/Parasitic Species:
Blainville's beaked whales are sometimes hunted by small cetacean hunters in various locations. Occasionally, they are also taken accidentally by Japanese tuna boats.
The IUCN Red List classifies Blainsville's beaked whales as "Data Deficient," meaning that there is insufficient information to determine the stability of their population or its trend. However, they appear to be fairly common in most warm waters, and are the most common of all the whales in their genus (Mesoplodon). Current threats include accidental and intentional hunting and ingesting pollution. Confusion by military sonar has caused them to wash up on beaches in large numbers. They may also be affected by climate change, but the potential impacts are not yet certain.
CITES: appendix ii
IUCN Red List of Threatened Species: data deficient
Blainville's beaked whales use echolocation to locate prey on deep dives. They produce two types of clicking sounds, each associated with a specific foraging phase. Search clicks, between 0.2 and 0.4 seconds, are sent during their diving phase in search of prey. Short burst clicks are buzz clicks emitted while capturing prey.
Communication Channels: acoustic
Perception Channels: tactile ; echolocation ; chemical
Fighting among males for access to females is believed to be common, as numerous long narrow scars are found on males. These are likely caused by the large, tusk-like teeth of males. Studies suggest they form harems, which consist of several females and a single dominant male.
Knowledge about reproduction habits of Blainville's beaked whales is very scarce. The estimated age of sexual maturity is 9 years. Mature females give birth to a single calf. Newborn calves are estimated to weigh around 60 kg and measure 1.9 to 2.6 m in length.
Average number of offspring: 1.
Average age at sexual or reproductive maturity (female): 9 years.
Average age at sexual or reproductive maturity (male): 9 years.
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual
Average age at sexual or reproductive maturity (female)
Sex: female: 3287 days.
Little is known about parental investment in this species, but female whales typically nurse calves. There is little parental investment in this species.
Blainville's beaked whale (Mesoplodon densirostris), or the dense-beaked whale, is believed to be the widest ranging mesoplodont whale. The French zoologist Henri de Blainville first described the species in 1817 from a small piece of jaw — the heaviest bone he had ever come across — which resulted in the name densirostris (Latin for "dense beak"). Off the northeastern Bahamas, the animals are particularly well documented, and a photo identification project started sometime after 2002.[3]
The body of Blainville's beaked whale is robust, but also somewhat compressed laterally compared with other mesoplodonts.[3] The males have a highly distinctive appearance, the jaws overarch the rostrum, like a handful of other species, but does it towards the beginning of the mandible and then sloped down into a moderately long beak. In adult males the crown of a tooth erupts from each side of the lower jaw as they reach maturity. Barnacles are often attached to the exposed tooth.[3] One of the more remarkable features of the whale is the extremely dense bones in the rostrum, which have a higher density and mechanical stiffness than any other bone yet measured. At present, the function of these bones is unknown, as the surrounding fat and the brittleness of the bone make it unlikely to be used for fighting. It has been suggested that it may play a role in echolocation or as ballast, but without sufficient behavioral observation, this cannot be confirmed.[4] The melon of the whale is flat and comparatively small. Coloration is dark bluish grey on top and lighter gray on the bottom, and the head can be brownish shading to light grey around the lip and the jaw.[3] Skin discoloration might be caused by diatoms.[5] They might have white oval scars possibly caused by cookie-cutter sharks. Adult males can also have long white ‘scratch’ scars. Males reach at least 4.4 m (14 ft 5 in) and 800 kg (1,800 lb), whereas females reach at least 4.6 m (15') and 1 tonne (2200 pounds). Juveniles are 1.9 m (6 ft 3 in) long when born and weigh 60 kg (130 lb). No data on lifespan is available.[3]
This species of beaked whale is found in tropical and warm waters in all oceans, and is considered to be the most extensively distributed member of Mesoplodon genus.[5] Sightings occur in higher latitudes probably in relation to warm water currents such as Gulf Stream and the Agulhas Current. Groups are regularly seen in at least three locations: Waianae coast, Hawaii; Society Islands of the South Pacific; northeastern Bahamas.[3]
The mean group size is 4.1 individuals.[6] There is no evidence of seasonal migration.[3] It inhabits deep, offshore water (656 to 3281 feet deep) and is associated with steep underwater geological structures.[5] Sub-adult males are found further offshore and in deeper water than adult males due to dominance hierarchy.[6] Blainville’s beaked whales have a long-term site fidelity meaning they return to the same area repeatedly or stay in the area for extended periods of time. Resight rate is higher for females than males as they are more likely to base their distribution based on prey abundance when males follow females to increase mating opportunity [7]
This species feeds primarily on squid and small fish[3] and cephalopods.[8]
Blainville's beaked whales do not capture prey by biting. They use suction feeding to capture prey. They create low pressure in the mouth by retracting tongue, and using throat grooves to expand throat volume. This creates a lower pressure in the mouth than the surrounding waters, allowing the whale to suck in water and whole prey.[9]
Blainville’s beaked whale shows similar foraging behaviour during the day and night, however the time spent on surface is greater during the night.[10]
Blainville's beaked whales can live in small cohesive groups of 3 to 7 individuals.[3] Groups consist of both sexes and combination of ages or might be segregated. Harems of several females and a single mature male have been observed in productive continental shelf areas (eg. Bahamas). Males compete for females which probably causes scarring on individuals.[5] The function of the group formation is protection (for females with small calves) and mating opportunity (for adult males).[11]
Two signals were identified with possible communicative function: fast series of ultrasonic frequencies modulated by clicks and harmonical rich short whistles with mean fundamental frequency of 12 kHz. Because Blainville's beaked whales almost exclusively vocalize while on their dives, most believe that they are using sound to help their foraging. However, while on their dives they will produce whistles which are most commonly known for communication among odontocetes rather than echolocation for foraging. [12]
Blainville’s beaked whales remain silent for up to 80% of the time, especially in depth shallower than 170m and during silent ascent from vocal dives. This behaviour might be a protection mechanism against shallow-diving predators such as killer whales.[12]
There is no evidence of seasonal migration.[3]
Beaked whales are among the longest and deepest divers of any cetaceans. Mean diving depth for Blainville’s beaked whale is 922m with maximum 1408 m. The species dives primarily to forage for food in the deep ocean, usually diving>800 m when foraging and can stay underwater for 48-68 min. For longer dives ascent rates are slower than descent rates. After a dive they spend an extensive period of time (66-155min) in the upper 50 m of the water column. [13]
In a study published in 2008, diving statistics of beaked whales were analyzed and no significant difference was found in diving behavior between day and night. For example, mean and max duration, number of deep dives, max depth, and ascent and descent rates were all calculated as equal during the day and night. However, the number of mid-depth dives was recorded to be six times higher during the day than at night. These results suggest that Blainville's beaked whales forage the same amount during the day and night, but switch to deeper-water prey at night.[14]
Lifespan estimate is unknown.[3] Sexual maturity might be reached at 9 years old.[5] Calving interval and gestation period are unknown.[15]
In 1817 Blainville named the species Delphinus densirostris, based on the description of a nine-inch piece of rostrum of unknown origin housed in the Paris Museum. It became one of the first beaked whales to be identified.[15] The second specimen, a complete skull sent from the Seychelles by a M. Leduc in 1839, was named Ziphius seychellensis by the English zoologist John Edward Gray in 1846; the French scientist Paul Gervais later placed this specimen in the genus Dioplodon ("two-toothed").[16][17] Sometimes called dense-beaked whale as the current Latin name (Mesoplodon densirostris) derives from densus for ‘dense’ and rostrum for ‘beak’ .[3] For management purposes, Blainville's beaked whales inhabiting U.S. waters have been divided into the Hawaiian, northern Gulf of Mexico, and western North Atlantic stocks.[5]
NOAA Fisheries presents estimates of population size of U.S. stocks (Hawaiian, northern Gulf of Mexico, western North Atlantic) in stock assessment reports .
Blainville’s Beaked Whale is protected throughout its range by CITES Appendix II and MMPA Protected.[5] The Blainville's beaked whale is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic Sea, North East Atlantic, Irish and North Seas (ASCOBANS) [18] and the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS).[19] The species is further included in the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (Western African Aquatic Mammals MoU) [20] and the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MoU).[21]
The beaked whale has occasionally been hunted, but has never been a specific target.[22]
Beaked whales are susceptible to detrimental effects of anthropogenic noise pollution because they use sound for hunting, communication and navigation.[23] The broadband ship noise can cause a change in beaked whale behaviour up to 5.2 km from the boat. Whales have been reported to move away from the noise source and decrease their activity level.[23] Sonar use during naval military activities have been associated with multiple strandings throughout their range.[5] Infrequent and unpredictable noise is perceived as a threat and influences whale behaviour. Response is especially strong in noise-free areas where whales show avoidance of the noise which might be associated with life-threatening increased energetic costs.[24]
Blainville’s beaked whales are occasionally reported as a bycatch throughout its range.[5][25]
Marine debris has been identified in the stomach of stranded Blainville’s Beaked Whale.[26] Marine debris ingestion was reported as a cause of death of beaked whales.[5]
For more information about ongoing work on Blainville’s Beaked Whale check BMMRO and Cascadia Research Collective
Adult male (in the Bahamas)
Mouth of adult female
A cow-calf pair surfacing
Blainville's beaked whale (Mesoplodon densirostris), or the dense-beaked whale, is believed to be the widest ranging mesoplodont whale. The French zoologist Henri de Blainville first described the species in 1817 from a small piece of jaw — the heaviest bone he had ever come across — which resulted in the name densirostris (Latin for "dense beak"). Off the northeastern Bahamas, the animals are particularly well documented, and a photo identification project started sometime after 2002.
