Tasmacetus shepherdi

Geographic Range

Shepherd’s beaked whales ( Tasmacetus shepherdi ) are native to the coasts and open waters of southwestern Australia, the Chatham Islands, New Zealand, and Tasmania. These waters are a part of the southwest and east regions of the Pacific, Atlantic, and Indian Oceans. This also includes the Ethiopian and Neotropical biogeographic regions. Shepherd’s beaked whales have been found stranded as far as 30° south latitude and just north of 50° south latitude. Sightings have also been recorded off the coast of Argentina, Juan Fernandez Islands in the South Pacific Ocean, and Tristan da Cunha in the South Atlantic.

• Biogeographic Regions
• ethiopian ethiopian
  • native native
• neotropical neotropical
  • native native
• australian australian
  • native native
• indian ocean
  • native native
• atlantic ocean atlantic ocean
  • native native
• pacific ocean pacific ocean
  • native native

Habitat

Shepherd’s beaked whales are a deep-diving species that stay in cold temperate marine waters. This species is thought to occasionally inhabit the continental shelf and canyons that are close to the coast. Donnelly et al. (2018) reported a group of 12 individuals off the coast of Western Victoria, Australia at a depth of 2000m below the water’s surface. The maximum depth this species has been recorded at is 3940m west of Kangaroo Island, Australia. Shepherd's beaked whales have also spotted at the water's surface.

• Habitat Regions
• saltwater or marine saltwater or marine

• Aquatic Biomes
• pelagic pelagic
• coastal coastal

Physical Description

A defining feature of both sexes of Shepherd’s beaked whales is that their upper and lower jaws have full sets of functional teeth and lack the two bones within the skull that form parts of the eye sockets and the nasal cavity in their palates.

Both males and females have apical teeth at the top of the lower jaw; in males, these teeth erupt from the gums and point forward, but for females they remain unerupted. Other defining features include dark patches around the eyes, paleness in the coloring around the head, and mid-dorsal line ventral to the blowhole.

Mature Shepherd’s beaked whales average total lengths of 6 to 7 meters, and males are typically larger than females. Both sexes have blue-brown and grey coloring along the ventral part of the body and the fluke (tail), not including the head or a patch between the dorsal fin and the fluke that is white and fades into dark blue-brown and grey. White coloring covers the dorsal portions of the whale around the throat, posteriorly to the belly, pectoral fins, and fades into the base of the fluke. The coloring pattern causes a “U” shape along the lateral part of the body. Adult whales are often found with scratches and scarring from what is believed to be boats or fishing nets.

Best et al. (2006) described a stranded juvenile male with a total length of 3.4m. Features such as skin roll lines on the flank (ribs) suggest that the calf might have still been paired with its mother. The juvenile did not have a major difference in color pattern, only described as having a muted coloring and lack of defining detail as compared to adults. The dark blue-grey and brown portions of the adults are described as appearing more olive green and blue in color in this juvenile. There is no information about the length or mass at birth for Shepherd’s beaked whales or the mass of the adults.

• Other Physical Features
• endothermic endothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Reproduction

Due to their deep-diving nature, very little is known about the mating behaviors of Shepherd’s beaked whales or how mating behaviors affect their social structures. Research suggests that these whales could be polyandrous due to females being seen traveling with multiple males. Shepherd's beaked whales are also spotted more in the up-welling season (November to May) which is thought to be their mating season.

• Mating System
• polyandrous polyandrous

Shepherd’s beaked whales are thought to be seasonal breeders during the up-welling season (from November to May) when the colder water rises to the ocean’s surface. They can reproduce multiple times throughout their lifetime but only give birth to one live offspring per breeding season. Breeding intervals are thought to be every 2 to 3 years. The estimated gestation for Shepherd’s beaked whales is 1 year. When the calves are born, they are up to 46% of their mothers’ total length. Calves are thought to be weaned a year after the birth or sometimes longer; one 3.4-meter calf was still observed with its presumed mother, suggesting an extended time with the parent. There is no further information on the time to weaning. Due to limited research, the only known length for sexually-mature Shepherd’s beaked whale females is 6.6 m and 7.0 for males. New et al. (2013) suggested that because survival is the main priority for adult females if they must support a calf past weaning, the females will delay the implantation of another fetus.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• viviparous viviparous
• delayed implantation delayed implantation

Based on research showing the relationship between energy and reproduction rates in Shepherd’s beaked whales, if food sources run low and they don’t have enough energy to support gestation, these whales will terminate gestation or lactation. Research suggests that females can delay pregnancy to store more energy to ensure a successful reproduction in the future. As calves age, their daily energy provided by their mothers declines at a steady rate until they are weaned. Calves are born through live birth and thought to remain with their mothers for about a year. Males provide no parental care beyond mating.

• Parental Investment
• precocial precocial
• female parental care female parental care
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
• pre-weaning/fledging
  • provisioning
    • female
• pre-independence
  • provisioning
    • female

Lifespan/Longevity

No data exist on the lifespan of Shepherd’s beaked whales. These whales are not kept in captivity. Research suggests the average maximum age is between 27 to 39 years old for all beaked whales in the family Ziphiidae. Based on mortality, Shepherd’s beaked whales that have been found stranded were aged between 12-15 years old (Holyoake et al., 2013), and in one case the specimen was 23 years old (Grandi et al., 2005). These whales are presumed to live longer, on average, than these ages. The oldest recorded beaked whale was a male Baird’s beaked whale Berardius bairdii estimated to be 84 years old by tooth layers (Macleod and Amico, 2006).

Behavior

Sightings of at-sea interactions suggest that Shepherd’s beaked whales are a very social species. During these encounters, they seemed to swim towards vessels; one interaction was reported to have lasted for up to 2 hours. Also, during at-sea interactions, the beaked whales displayed noninvasive behavior. Similar to the gingko-toothed beaked whales Mesoplodon , also a member of the Ziphiidae family, when Shepherd’s beaked whales are surfacing they travel in synchronized groups of 2 to 14 individuals. These are tight groups with individuals staying within less than 5 body lengths apart. Some observations have seen these groups break into smaller subgroups, but still lightly packed and traveling in the same synchronized manner. Other at-sea behaviors that were observed include breaching, where the whole body leaves the water, lob-tailing which involves slapping the dorsal or ventral side of the tail against the water, and spy hopping, where they poke their head above the water to get a better view of their surroundings. Diving behaviors include dives ranging from 5 to 15 minutes long and surfacing in 4 to 17 minutes intervals. During surfacing, the beaked whales will blow in 9 to 13-second intervals.

• Key Behaviors
• natatorial natatorial
• diurnal diurnal
• motile motile
• social social

Home Range

The home range of the Shepherd's beaked whale is unreported. They are not suspected to defend a territory.

Communication and Perception

There are two types of vocalizations known to be used by Shepherd’s beaked whales. For foraging and catching prey, echolocation is used to detect the distance and size of prey. Leunissen et al. (2018) recorded this species using another form of communication involving burst pulse clicks that could be used for socialization or in prey capture. Research suggests that these beaked whales may have their own distinct vocalization based on a low FM near the water’s surface at 100-300m. There are no current data on these vocalizations in deep waters.

Shepherd’s beaked whales use echolocation during foraging to detect their prey at frequencies above human hearing. Cetaceans are known for having good eyesight that adapts to diving into dark waters or resurfacing. All cetaceans also have the ability to taste and smell.

Shepherd’s beaked whales use tactile perception in social relationships, to care for their young, and for mating.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• ultrasound ultrasound
• echolocation echolocation
• chemical chemical

Food Habits

On average, Shepherd’s beaked whales eat about 758g of food a day. Based on the stomach contents of a male Shepherd’s beaked whale, Best et al. (2014) reportedly found 80 individuals from the cephalopod family and 64 fish. Also reported were eight fish species and 13 species of cephalopods in the stomach contents of two stranded whales. Of the Cephalopods, present there were six families of squid including: Histioteuthidae, Cranchiidae, Mastigoteuthidae, Enoploteuthidae, and Brachioteuthidae. Squid in the genus Octopoteuthis (family Octopoteuthidae) and one species Lycoteuthis lorigera (family Lycoteuthidae) also were included in this list. These cephalopods comprised 50.5% of the contents and included those from the Family Histioteuthidae (30.4%) and Family Octopoteuthidae (20.1%). Six families of fish were identified: Trachicichthyidae, Berycidae, Opisthoproctidae, Lophiidae, Ophidiidae, and Myctophidae. One species of spothead lantern fish Diaphus metopoclampus also was found in stomach contents, as was an unknown fish in order Gadiformes.

Based on the feeding habits of the Shepherd’s beaked whales, it is suggested that this species changes its feeding habits by moving back and forth between continental slopes and small geographic landforms underwater, known as seamounts, to take advantage of fish that swim in schools. Shepherd’s beaked whales use echolocation to find prey and then create suction using their beaks to pull in prey.

• Primary Diet
• carnivore carnivore
  • piscivore piscivore
  • molluscivore molluscivore

• Animal Foods
• fish
• mollusks

Predation

Shepherd’s beaked whales have no natural predators. However, due to human ( Homo sapiens ) activities such as fishing, boating, and acoustic sound pollution, many of these beaked whales have been found stranded or caught in fishing nets. There is no research that suggests that Shepherd’s beaked whales have developed any anti-predatory defense mechanisms.

Ecosystem Roles

Shepherd’s beaked whales eat a variety of organisms such as cephalopods and many species of fish. Shepherd’s beaked whales have no predators. In one dissection of a Shepherd's beaked whale, there were no parasites present (Mead and Payne, 1975).

Economic Importance for Humans: Positive

Because there is little information that is known about Shepherd’s beaked whales, they currently serve no economic benefit to humans.

Economic Importance for Humans: Negative

Shepherd’s beaked whales have been known to get caught in fishing nets, but there is no research providing more information about further possible negative economic impacts on humans.

Conservation Status

According to IUCN Red List, the ranking for Shepherd’s beaked whales is data deficient. CITES has included them in Appendix II, which states that the species is not endangered by extinction but can be threatened by trade unless it is controlled. These beaked whales have no special status on the US Federal List or State of Michigan List. More research is needed to find the impacts of threats on this species.

There are no major threats to Shepherd’s beaked whales because they are not hunted or intentionally fished and information about interactions with fisheries is limited. The stomach contents of Shepherd’s beaked whales have revealed that the intake of plastic has led to the death of stranded individuals. Like other whales, they are also sensitive to anthropogenic sounds that are generated by sonar and seismic surveys.

Conservation efforts for this species include action needed for research on population size, distribution patterns, life history, ecology, threats, and monitoring Shepherd’s beaked whales’ population trends. The IUCN Red List states that they are included in international legislation and subject to trade controls. Sightings, strandings, and a limited number of records suggest this species is rare.

Additional Links

Encyclopedia of Life

Contributors

Abigail Naughton (author), Radford University, Karen Powers (editor), Radford University, Victoria Raulerson (editor), Radford University, Christopher Wozniak (editor), Radford University, Genevieve Barnett (editor), Colorado State University.

References

Baumann-Pickering, S., M. McDonald, A. Simonis, A. Solsona Berga, K. Merkens, E. Oleson, M. Roch, S. Wiggins, S. Rankin, T. Yack, J. Hildebrand. 2013. Species-specific beaked whale echolocation signals. The Journal of the Acoustical Society of America , 134/3: 2293-2301.

Best, P., A. Pym, R. Pitman L., A. Van Helden. 2006. Shepherd's beaked whale (Tasmacetus shepherdi): Information on appearance and biology based on strandings and at-sea observations. Marine Mammal Science , 22/3: 744-755.

Best, P., M. Smale, J. Glass, K. Herian, S. Von Der Heyen. 2014. Identification of stomach contents from a Shepherd's beaked whale Tasmacetus shepherdi stranded on Tristan da Cunha, South Atlantic. Journal of Marine Biological Association of the United Kingdom , 94/6: 1093-1097.

Braulik, G. 2018. "Tasmacetus shepherdi" (On-line). The IUCN Red List of Threatened Species 2018: e.T21500A50377701. Accessed September 07, 2021 at https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T21500A50377701.en .

Donnelly, D., P. Ensor, P. Gill, R. Clark, K. Evans, M. Double, T. Webster, W. Rayment, N. Schmitt. 2018. New diagnostics descriptions and distribution information for Shepherd's beaked whale (Tasmacetus shepherdi) off southern Australia and New Zealand. Marine Mammal Science , 34/3: 829-840.

Grandi, F., A. Buren, E. Crespo, N. Garcia, G. Svendsen, S. Dans. 2005. Record of a specimen of Shepherd's beaked whale (Tasmacetus shepherdi) from the coast of Santa Cruz, Argentina, with notes on age determination. Lation Journal of Aquatic Mammals , 4/2: 97-100.

Groom, C., D. Coughran, H. Smith. 2014. Records of beaked whales (family Ziphiidae) in western Australian waters. Marine Biology Records , 50/7: 1-13.

Havia, M., D. Arcucci, J. Belgrano, F. Cipriano, M. Failla, C. Gasparrou, N. Hodgins, F. Krohling, F. Reyes, V. Tossenberger, M. Iniguez. 2011. Strandings of six beaked whales in Santa Cruz province, southern Argentina. Journal to Cetacean Resource Management , 7: 1-8.

Holyoake, C., D. Holley, P. Spencer, C. Salgado-Kent, D. Coughran, B. Lars. 2013. Northernmost record of Shepherd's beaked whale (Tasmacetus shepherdi) - A morphological and genetic description from a stranding from Shark Bay, Western Australia. Pacific Conservation Biology , 19/2: 169-174.

Jefferson, T., M. Webber, P. Pitmas. 2015. Marine Mammals of the World : A Comprehensive Guide to their Identification . Amsterdam, Netherlands: Elsevier.

Leunissen, E., T. Webster, W. Rayment. 2018. Characteristics of vocalisations recorded from free-ranging Shepherd’s beaked whales, Tasmacetus shepherdi. Journal of the Acoustical Society of America , 144/5: 2701-2708.

Macleod, C., A. Amico. 2006. A review of beaked whale behaviour and ecology in relation to assessing and mitigating impacts of anthropogenic noise. Journal Cetacean Research and Management , 7/3: 211-221.

Mead, J. 1985. Survey of reproductive data for the beaked whales (Ziphiidae). Report of the International Whaling Commission , 6: 91-96.

Mead, J., R. Payne. 1975. A specimen of the Tasman beaked whale, Tasmacetus shepherdi, from Argentina. Journal of Mammalogy , 56/1: 213-218.

New, L., D. Moretti, S. Hooker, D. Costa, S. Simmons. 2013. Using energetic models to investigate the survival and reproduction of beaked whales (family Ziphiidae). PLOS ONE , 8/7: e68725. Accessed October 12, 2021 at https://doi.org/10.1371/journal.pone.0068725 .

Riccialdelli, L., N. Viola, H. Panarello, N. Goodall. 2017. Evaluating the isotopic niche of beaked whales from the southwestern South Atlantic and Southern Oceans. Marine Ecology Progress Series , 581: 183-198.

Thompson, C., P. Bouchet, J. Meeuwig. 2019. First underwater sighting of Shepherd's beaked whale (Tasmacetus shepherdi). Marine Biodiversity Records , 12: 6. Accessed August 24, 2021 at https://doi.org/10.1186/s41200-019-0165-6 .

Environmental Protection Agency at Wellington. Exclusive economic zone and continental shelf (Environmental effects) Act 2012 (“the Act”). Ph 03 9405524. New Zealand: Royal Forest and Bird Protection Society of New Zealand Inc. 2017.