Overview

Ziphius cavirostris – G. Cuvier, 1823

ANIMALIA – CHORDATA – MAMMALIA – ARTIODACTYLA – ZIPHIIDAE – Ziphius – cavirostris 

Common Names: Cuvier’s Beaked Whale, Goose-beaked Whale, Goosebeak Whale (English), Cuvier se Snoetwalvis (Afrikaans)

Synonyms: Ziphius cavirostris Cuvier, 1823; Hyperoodon capensis Gray, 1865 

Taxonomic Note:  

Cuvier’s Beaked Whale (Ziphius cavirostris) is the only species in the monotypic genus Ziphius (Rice 1998, Dalebout et al. 2005). During the 19th century numerous specimens of Cuvier’s Beaked Whales were described as new species but none of them have been accepted as valid and a single species is recognised to occur throughout its range. 

Red List Status: DD – Data Deficient, (IUCN version 3.1) 

Assessment Information

Assessors: James, B.S.¹ & da Silva, J.² 

Reviewer: Patel, T.³ 

Institutions: ¹University of Cape Town, ²South African National Biodiversity Institute, ³Endangered Wildlife Trust 

Previous Assessors: Cockcroft, V. & Relton, C. 

Previous Reviewers: Hofmeyr, G.J.G. 

Previous Contributors: Elwen, S., Findlay, K., Meÿer, M., Oosthuizen, H., Plön, S. & Child, M.F. 

Assessment Rationale 

There is no information pertaining to the population abundance of beaked whales within the assessment region, and they are generally considered to be naturally rare. The current threats to this species are climate change, whaling, military sonar, vessel noise, seismic airguns, echosounders, entanglement, vessel strikes, persistent organic pollutants, toxic metals, plastics and oil spills. In addition, marine noise pollution, usually in the form of seismic surveys, navy operations and marine construction have been identified as emerging and escalating threats to beaked whales. Anecdotal evidence suggests that beaked whales are more vulnerable to marine noise (particularly mid-frequency active sonar) than other cetaceans. The compounding influences of these threats could potentially cause beaked whale population declines. With the exception of the Southern Bottlenose Whale, beaked whales in the assessment region are listed as Data Deficient, which highlights the need for additional research, specifically on assessments of abundance, changes in abundance, distribution and anthropogenic threats, including marine noise pollution. In other parts of the world there have been repeated instances of mass strandings of Cuvier’s Beaked Whales associated with mid to low frequency active sonar. It has been suggested that these sonar effects could extend to seismic surveys (applicable to all beaked whale species). Within the assessment region, only 26 strandings have been recorded. Thus, although this species is presumably common and abundant in South African waters, we list as Data Deficient until abundance and the effects of marine noise pollution can be investigated. Reassessments should follow when new data are available.  

Regional population effects: Beaked whales are considered to be wide-ranging, seasonally migrating species. Those present within South African waters in summer presumably spend winters in the southern oceans, thus there are no barriers to dispersal, and rescue effects are possible. 

Reasons for Change 

Reason(s) for Change in Red List Category from the Previous Assessment: No change 

Red List Index 

Red List Index: No change 

Recommended citation: James BS & da Silva JM. 2025. A conservation assessment of Ziphius cavirostris. In Patel T, Smith C, Roxburgh L, da Silva JM & Raimondo D, editors. The Red List of Mammals of South Africa, Eswatini and Lesotho. South African National Biodiversity Institute and Endangered Wildlife Trust, South Africa.

Regional Distribution and occurrence

Geographic Range

R. Z.cavirostrisis distributed most extensively of all Ziphiidae species (Heyning 1989, 2002), occurring within all oceans from the tropics to cold temperate and the lower-latitude polar regions across both the northern and southern hemisphere (Jefferson et al. 1993), predominantly within deep, open waters. They are only absent from shallow waters and the high-latitude polar regions. They have also been recorded within enclosed seas, including the Gulfs of California and Mexico, the Mediterranean (Podesta et al. 2005) and Caribbean Seas, as well as the Sea of Okhotsk and the Sea of Japan. Within southern Africa, this species has been documented from Namibia, and the Western and Eastern Cape. Additionally, Ross (1984) recorded two individuals taken by whalers from the Durban land station in waters deeper than 1,000 m, as well as a sighting of this species 372 km due south of Cape St Blaise, South Africa in 1975, where the ocean depth exceeds 3,000 m. 

Elevation / Depth / Depth Zones 

Elevation Lower Limit (in metres above sea level): (Not specified) 

Elevation Upper Limit (in metres above sea level): (Not specified) 

Depth Lower Limit (in metres below sea level): (Not specified) 

Depth Upper Limit (in metres below sea level): (Not specified) 

Depth Zone: (Not specified) 

Map

Figure 1. Distribution records for Cuvier’s Beaked Whale (Ziphius cavirostris) within the assessment region (South Africa, Eswatini and Lesotho). Note that distribution data is obtained from multiple sources and records have not all been individually verified.

Biogeographic Realms 

Biogeographic Realm: Afrotropical, Australasian, Indomalayan, Nearctic, Neotropical, Oceanian, Palearctic 

Occurrence 

Countries of Occurrence 

Large Marine Ecosystems (LME) Occurrence 

Large Marine Ecosystems: (Not specified) 

FAO Area Occurrence 

Climate change

The specific effects of climate change on Cuvier’s Beaked Whales is currently unknown however it has been suggested that similar to other cetaceans, beaked whales will likely undergo extensive range shift towards higher latitudes where they may be exposed to additional stressors such as increased noise exposure, interactions with fisheries, incidence of disease outbreaks and risk of ship strikes as well as reduced prey availability (Feyrer et al. 2024). Drastic reductions in suitable habitat and available prey for beaked whales due to climate change may result in future population declines, which would be difficult to quantify give the scarcity of abundance, life history and population level information we currently have for many beaked whale species. 

Population information

Due to their wide distribution, affiliation with deep water habitats, and cryptic nature, there are very little data pertaining to the population abundance and trends of Ziphiidae species in South African waters. 

Z. cavirostris is considered the most common of all beaked whales world-wide (Heyning 2002); however, sightings at sea are still rare in comparison to other cetaceans and little is known about the population structure of this species. Estimates of abundance are available for a number of regions, but these may be somewhat unreliable considering the rarity of sightings and their ability to dive to extreme depths (Caretta et al. 2004). Dalebout et al. (2005) estimate a global population abundance of between 456,000 and 916,000 breeding adults, however, these results should be treated with caution. Cuvier’s Beaked Whales show little movements between ocean basins, resulting in regional subpopulations, as has been revealed by molecular investigations (see Population Genetics section) (Dalebout et al. 2005; Onoufriou et al. 2022; Tonay et al. 2024). 

Continuing decline in mature individuals? (Not specified) 

Extreme fluctuations in the number of subpopulations: (Not specified) 

Continuing decline in number of subpopulations: (Not specified) 

All individuals in one subpopulation: (Not specified) 

Number of mature individuals in largest subpopulation: (Not specified) 

Number of Subpopulations: (Not specified) 

Quantitative Analysis 

Probability of extinction in the wild within 3 generations or 10 years, whichever is longer, maximum 100 years: (Not specified) 

Probability of extinction in the wild within 5 generations or 20 years, whichever is longer, maximum 100 years: (Not specified) 

Probability of extinction in the wild within 100 years: (Not specified) 

Population genetics

Single nucleotide polymorphisms (SNPs) and mitogenomes revealed substantial hierarchical structure within this species at a global scale, corresponding to the Atlantic, Indo-Pacific and the Mediterranean Sea regions (Onoufriou et al. 2022; Tonay et al. 2024). Within major ocean basins, several evolutionarily distinct units (ESUs) have been identified, with animals from the assessment region grouping with animal from Australia and New Zealand to form the southern Indo-Pacific ESU (Onoufriou et al. 2022). Unfortunately, no measure of effective population size (Ne) was reported; however, through reanalysis of the data, this metric may be obtainable, provided adequate samples are incorporated.   

Based on the available information, one of the two genetic indicators in the Convention of Biological Diversity’s Global Biodiversity Framework can be quantified – the complementary indicator – proportion of populations maintained with a species. Given that 1 genetic distinct subpopulation is known from the region and no other subpopulations are known to have gone extinct, this indicator would receive a value of 1.0 (1/1 subpopulation remains). 

Habitats and ecology

Little is known about the key behavioural and ecological characteristics of beaked whales. Typically, these species occur in deep, offshore waters, and are considered to have long, deep-diving capabilities. Their occurrence is generally associated with topographic features, including slopes, escarpments, canyons and oceanic islands (Macleod et al. 2006). The stomach contents of stranded beaked whales suggest that their primary food source includes deep-water, mesopelagic cephalopods, although MacLeod et al. (2003) found that benthic fish and crustaceans also constitute important prey items for these species. Ziphius and Hyperoodon spp. prey upon significantly larger species, compared to Mesoplodon spp. (MacLeod et al. 2003). 

Similar to other beaked whales, Z. cavirostris is most frequently associated with deep waters for feeding. Dive durations of 30 minutes (Miyazaki & Wada 1976) and 40 minutes have been recorded. Using suction techniques (Heyning & Mead 1996), they consume mostly deep-sea squid, but also fish and crustaceans (MacLeod et al. 2003), feeding both within the water column as well as near the bottom. Sexual maturity is reached at lengths of over 5.5 m (Omura et al. 1955; Nishiwaki & Oguro 1972), and breeding and calving of this species may span over a number of months (Ross 1984). Calves are born at lengths of approximately 2.6 m. 

Ecosystem and cultural services: Marine mammals integrate and reflect ecological variation across large spatial and long temporal scales, and therefore they are prime sentinels of marine ecosystem change; migratory whales may be used to investigate broad-scale shifts in ecosystems (Moore 2008). 

IUCN Habitats Classification Scheme 

Life History 

Generation Length: (Not specified) 

Age at Maturity: Female or unspecified: (Not specified) 

Age at Maturity: Male: (Not specified) 

Size at Maturity (in cms): Female: (Not specified) 

Size at Maturity (in cms): Male: (Not specified) 

Longevity: (Not specified) 

Average Reproductive Age: (Not specified) 

Maximum Size (in cms): (Not specified) 

Size at Birth (in cms): 270 cm

Gestation Time: (Not specified) 

Reproductive Periodicity: (Not specified) 

Average Annual Fecundity or Litter Size: (Not specified) 

Natural Mortality: (Not specified) 

Does the species lay eggs? No 

Does the species give birth to live young: Yes

Does the species exhibit  parthenogenesis: No

Does the species have a free-living larval stage? No

Does the species require water for breeding? Yes

Movement Patterns 

Movement Patterns: (Not specified) 

Congregatory: (Not specified) 

Systems 

System: Marine 

General Use and Trade Information

In general, beaked whales in the southern hemisphere are not utilised or traded commercially. Historically, Z. cavirostris was hunted opportunistically off the coast of Japan during hunts specifically aimed at Baird’s Beaked Whales (Berardius bairdii) (Omura et al. 1955; Nishiwaki & Oguro 1972). Although commercial hunting of Cuvier’s Beaked Whales has ceased, products pertaining to this species are still for sale in certain Asian markets, suggesting that this species is either susceptible to accidental bycatch, or may be subject to unreported direct exploitation. Small-scale hunting of this species has also occurred in other regions, but there are no records of this within the assessment region. 

National Commercial Value: Yes 

International Commercial Value: No 

 Is there harvest from captive/cultivated sources of this species? Yes 

Harvest Trend Comments: (Not specified) 

Threats

The current threats to this species are climate change, whaling, military sonar, vessel noise, seismic airguns, echosounders, entanglement, vessel strikes, persistent organic pollutants, toxic metals, plastics and oil spills (Feyrer et al. 2024).

Anthropogenic noise pollution has become an increasing and well-known threat to beaked whales, as they appear to be more vulnerable to noise pollution than other cetacean species (Dalebout et al. 2005). A number of mass stranding events involving beaked whales have been attributed to high-powered navy sonar (Simmonds & Lopez-Jurado 1991; Mignucci-Giannoni 1996; Frantzis 1998, 2004; Balcomb & Claridge 2001; Jepson et al. 2003; Cox et al. 2006). Although the exact mechanistic causes are not clearly understood, the formation of gas bubbles (Fernández et al. 2005), appears to be attributed to sonar activities and noise pollution (Cox et al. 2006). Jepson et al. (2003) described the physiological damage, including acute and chronic tissue damage, inflicted on beaked whales by the deployment of military sonar at the Canary Islands. Although other beaked whale species were impacted, Cuvier’s Beaked Whale was affected most severely. Mass strandings of Cuvier’s Beaked Whales attributed to the use of active sonar by navy vessels has been documented on a number of occasions during the late 1990s and early 2000s in the Mediterranean (Frantzis 1998), the Bahamas (Balcomb & Claridge 2001), and Japan (Brownell et al. 2004). Additionally, a seismic survey is thought to be responsible for the stranding of two individuals in the Gulf of California (Malakoff 2002). It is believed that loud sounds may cause animals to panic and surface rapidly, thus resulting in rapid decompression; alternatively, the mid-frequency sonar activity may cause vibrations that form air bubbles in the individual’s tissues (Jepson et al. 2003). In 2004 a moratorium on naval activities in the Canary Islands was enforced by the Spanish government, and since then no mass stranding events have occurred in this area (Fernández et al. 2013). Within the assessment region, marine noise pollution is intensifying due to coastal industrial development, shipping traffic and energy exploration, and thus represents a potentially severe threat. 

Plastic pollution is a large-scale and increasing problem in all marine environments. The ingestion of plastic marine pollution has been documented in several species of beaked whales and may eventually lead to mortality as a result of choking, a reduction in appetite or starvation (e.g. Scott et al. 2001).  

Accidental entanglement of beaked whales in fisheries is widespread, particularly in deep-water gillnets, although the number of recorded mortalities is not high. Extensive gillnet and longline fishing practises throughout the ranges of many beaked whales may become an increasing risk to these species as a result of accidental entrapment and drowning. Julian & Beeson (1998) documented the annual mortality of Cuvier’s Beaked Whales as between 22 and 44 individuals accidentally caught in drift gillnets off California. 

The expansion of high-latitude fisheries, such as those directed at Antarctic Toothfish (Dissostichus mawsoni), which are largely unregulated and illegal, threaten the food stocks available for large cetaceans such as beaked whales. There is substantial evidence of large-scale reductions in many predatory fish populations (Baum et al. 2003, 2005; Polacheck 2006; Sibert et al. 2006), over-fishing and the collapse of several important “prey” fish stocks world-wide (e.g. Jackson et al. 2001). Although the effects of anthropogenic fish exploitation and the subsequent ecosystem changes on beaked whales is considered to be fairly low in comparison to other cetaceans in the Pacific Ocean (Trites et al. 1997), the degree of impact associated with high-latitude fisheries world-wide is largely unknown and could result in population declines. 

The marine-related threats associated with global climate change may pose unquantified and complex threats to beaked whales, particularly within cool temperate and cold Antarctic habitats (Learmonth et al. 2006). Increasing ocean temperatures may result in range shift or contraction (Learmonth et al. 2006); however, no direct predictions pertaining to the direction or size of these shifts in range are currently known. 

Unlike many whale species, beaked whales have not experienced large-scale historic or recent exploitation for meat or other products. This may be attributed to their general scarcity and inconspicuous nature, deep-sea distributions and/or deep-diving behaviour. Cuvier’s Beaked Whales have been caught opportunistically by Japanese whaling operations directed at Berardius species, as well as in the Caribbean, Indonesia, Taiwan and South America as bycatch in other direct fisheries (Heyning 1989; Jefferson et al. 1993). Between 3 and 35 Z. cavirostris individuals are reported to have been caught annually in Japan during the 1950s (Omura et al. 1955); however, no direct takes of this species were reported two decades later (Nishiwaki & Oguro 1972). 

Conservation

More research into the distribution, abundance, migration patterns, bycatch rate and diet of beaked whales is essential for the effective development of species-specific mitigation measures for these species in South African waters. Mitigation measures associated with anthropogenic marine noise is probably most vital for Ziphiidae species locally and world-wide. The Parties to the UNEP Convention on the Conservation of Migratory Species of Wild Animals (CMS) Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS) suggested in 2004 that anthropogenic activities that produce high-intensity marine noise pollution should be avoided in areas of high Cuvier’s Beaked Whale concentration. Due to their cryptic nature, mitigation of noise pollution based on observation is likely to be ineffective for these species. Additionally, avoidance of beaked whale habitats in South African waters is currently challenging due to their wide distribution, and the lack of data pertaining to habitat preferences and geographical extent across this region. 

Passive acoustic monitoring is a valuable technique used to detect marine mammals in order to modify marine activities so as to avoid the animals, decrease the amplitude or temporarily stop the source of sound when animals are within a critical distance (Barlow & Gisiner 2006). Although beaked whales are acoustically difficult to detect, all species are assumed to give off echolocation clicks, some may also produce whistles (Dawson et al. 1998; MacLeod & D’Amico 2006). However, Cuvier’s and Blainville’s Beaked Whales have been found to only produce echolocation clicks when they are several hundred metres deep. Generally, the clicks of Ziphiidae species are more narrow-banded than those of other marine mammals of a similar frequency, thus electronic filtering methods may be more effective than other methods (Barlow & Gisiner 2006). 

Maintaining sightings records of beaked whales, during ship-based surveys directed at other species, is a valuable means with which to monitor the distribution and abundance of these cryptic and unknown species in South African waters. 

All Ziphiidae species within the assessment region are listed either on Appendix I or II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). 

Recommendations for managers and practitioners:  

• Critical beaked whale habitats, and areas of high beaked whale concentration should be identified, so as to effectively mitigate the effects of noise pollution.  
• Although species-specific monitoring is deemed unnecessary for Ziphiidae species in the assessment region, sightings data should be recorded during systematic monitoring of other cetacean species.  
• Establish a nationwide strandings network and databases (comprised of whale-watching operators, coastal protected areas, police stations, hotels, etc.) to gather and pool information.  

Research priorities:  

• Population size and trend estimates.  
• Effects of marine noise pollution and plastic pollution on beaked whale populations.  
• The identification of high concentration areas in South African waters, including distributional limits, seasonal movements and diving behaviour. 
• Diet, reproduction and general biology. 

Encouraged citizen actions:  

• Report strandings east of Mossel Bay to the Port Elizabeth Museum, and west of Mossel Bay to Iziko Museums, Cape Town.  
• Report sightings on virtual museum platforms (for example, iNaturalist and MammalMAP) to help with mapping geographical distribution.  
• Avoid using plastic bags.  
• Save electricity and fuel to mitigate CO₂ emissions and hence the rate of climate change.  

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