Overview

Mesoplodon densirostris – (Blainville, 1817)

ANIMALIA – CHORDATA – MAMMALIA – ARTIODACTYLA – ZIPHIIDAE – Mesoplodon – densirostris 

Common Names: Blainville’s Beaked Whale, Atlantic Beaked Whale, Dense Beaked Whale (English), Blainville se Snoetwalvis (Afrikaans), Ballena de Pico de Blainville, Zifio de Blainville (Spanish; Castilian), Blainvilles næbhval (Danish), Blainvilles spisshval (Norwegian), Kobuha kujira (Japanese), Króksnjáldri (Icelandic), Mésoplodon de Blainville (French)
Synonyms: Delphinus densirostris Blainville, 1817 

Taxonomic Note:
Blainville’s Beaked Whales (Mesoplodon densirostris) is one of 15 species of Mesoplodon with a worldwide range in tropical and warm-temperate waters. No subspecies are currently recognised. 

Red List Status: Data deficient

Assessment Information

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

Reviewers: Patel, T.³ & Purdon, J.^4,5 

Institutions: ¹University of Cape Town, ²South African National Biodiversity Institute, ³Endangered Wildlife Trust, ⁴TUT Nature Conservation, ⁵University of Pretoria 

Previous Assessors & Reviewers: Relton, C., Cockcroft, V. & 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 main current threats for this species are climate change, whaling, military sonar, vessel noise, entanglement, depredation, 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.  

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 Mesoplodon densirostris. 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 

M. densirostris is considered the most widely distributed species of this genus (Pitman 2002; Macleod et al. 2006), occurring in all oceans except the Arctic with a preference for temperate and tropical waters of the Atlantic, Pacific and Indian Oceans (Mead 1989; Allen et al. 2011). Sightings and strandings are common around oceanic islands and archipelagos, for example Hawaii, the Society Islands, Mauritius and the Seychelles. As one of the most tropical beaked whales, this species often occurs within enclosed, deep, warm waters, including the Caribbean Sea, the Sea of Japan and the Gulf of Mexico. Within the assessment region, this species may utilise the warm waters of the Agulhas Current as a channel to the coast from tropical waters (Ross 1984). It is the beaked whale most recorded stranded on the South African coastline, these events having a primarily warm temperate distribution (Hofmeyr et al. 2014). Strandings have been recorded on both the east and west coasts of South Africa however Blainville’s beaked whales are more likely to be found in the warm waters of the Agulhas current on the south and east coasts (Ross 1984; Findlay et al. 1992). 

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) 

Biogeographic Realms 

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

Map

Figure 1. Distribution records for Blainville’s Beaked Whale (Mesoplodon densirostris) 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.

Countries of Occurrence 

Country	Presence	Origin	Formerly Bred	Seasonality
Angola	Extant	Native	–	–
Anguilla	Presence Uncertain	Native	–	–
Antigua and Barbuda	Presence Uncertain	Native	–	–
Argentina	Presence Uncertain	Native	–	–
Aruba	Presence Uncertain	Native	–	–
Australia	Extant	Native	–	–
Australia -> New South Wales	Extant	Native	–	–
Australia -> Northern Territory	Extant	Native	–	–
Australia -> Queensland	Extant	Native	–	–
Australia -> South Australia	Extant	Native	–	–
Australia -> Tasmania	Extant	Native	–	–
Australia -> Western Australia	Extant	Native	–	–
Bahamas	Extant	Native	–	–
Bangladesh	Presence Uncertain	Native	–	–
Barbados	Presence Uncertain	Native	–	–
Belize	Extant	Native	–	–
Benin	Presence Uncertain	Native	–	–
Bermuda	Presence Uncertain	Native	–	–
Bonaire, Sint Eustatius and Saba	Extant	Native	–	–
Brazil	Extant	Native	–	–
British Indian Ocean Territory	Presence Uncertain	Native	–	–
Brunei Darussalam	Presence Uncertain	Native	–	–
Cabo Verde	Extant	Native	–	–
Cambodia	Presence Uncertain	Native	–	–
Cameroon	Extant	Native	–	–
Canada	Extant	Native	–	–
Canada -> Nova Scotia	Extant	Native	–	–
Cayman Islands	Extant	Native	–	–
Chile	Extant	Native	–	–
China	Extant	Native	–	–
Cocos (Keeling) Islands	Extant	Native	–	–
Colombia	Extant	Native	–	–
Comoros	Extant	Native	–	–
Congo	Presence Uncertain	Native	–	–
Congo, The Democratic Republic of the	Presence Uncertain	Native	–	–
Cook Islands	Presence Uncertain	Native	–	–
Costa Rica	Extant	Native	–	–
Cuba	Presence Uncertain	Native	–	–
Curaçao	Extant	Native	–	–
Côte d’Ivoire	Presence Uncertain	Native	–	–
Djibouti	Presence Uncertain	Native	–	–
Dominica	Presence Uncertain	Native	–	–
Dominican Republic	Presence Uncertain	Native	–	–
Ecuador	Extant	Native	–	–
El Salvador	Presence Uncertain	Native	–	–
Equatorial Guinea	Presence Uncertain	Native	–	–
Eritrea	Presence Uncertain	Native	–	–
Fiji	Extant	Native	–	–
France	Presence Uncertain	Native	–	–
French Guiana	Presence Uncertain	Native	–	–
French Polynesia	Presence Uncertain	Native	–	–
Gabon	Presence Uncertain	Native	–	–
Gambia	Presence Uncertain	Native	–	–
Ghana	Presence Uncertain	Native	–	–
Gibraltar	Presence Uncertain	Native	–	–
Grenada	Presence Uncertain	Native	–	–
Guadeloupe	Presence Uncertain	Native	–	–
Guam	Extant	Native	–	–
Guatemala	Extant	Native	–	–
Guinea	Presence Uncertain	Native	–	–
Guinea-Bissau	Presence Uncertain	Native	–	–
Guyana	Extant	Native	–	–
Haiti	Presence Uncertain	Native	–	–
Honduras	Extant	Native	–	–
Hong Kong	Presence Uncertain	Native	–	–
India	Extant	Native	–	–
Indonesia	Extant	Native	–	–
Iran, Islamic Republic of	Presence Uncertain	Native	–	–
Ireland	Presence Uncertain	Native	–	–
Jamaica	Presence Uncertain	Native	–	–
Japan	Extant	Native	–	–
Kenya	Extant	Native	–	–
Kiribati	Extant	Native	–	–
Liberia	Presence Uncertain	Native	–	–
Madagascar	Extant	Native	–	–
Malaysia	Extant	Native	–	–
Maldives	Presence Uncertain	Native	–	–
Marshall Islands	Extant	Native	–	–
Martinique	Extant	Native	–	–
Mauritania	Extant	Native	–	–
Mauritius	Extant	Native	–	–
Mayotte	Extant	Native	–	–
Mexico	Presence Uncertain	Native	–	–
Micronesia, Federated States of	Extant	Native	–	–
Montserrat	Presence Uncertain	Native	–	–
Morocco	Extant	Native	–	–
Mozambique	Extant	Native	–	–
Myanmar	Extant	Native	–	–
Namibia	Extant	Native	–	–
Nauru	Extant	Native	–	–
New Caledonia	Extant	Native	–	–
New Zealand	Extant	Native	–	–
New Zealand -> Chatham Is.	Extant	Native	–	–
New Zealand -> North Is.	Extant	Native	–	–
Nicaragua	Extant	Native	–	–
Nigeria	Extant	Native	–	–
Niue	Presence Uncertain	Native	–	–
Northern Mariana Islands	Extant	Native	–	–
Oman	Extant	Native	–	–
Pakistan	Extant	Native	–	–
Palau	Extant	Native	–	–
Panama	Extant	Native	–	–
Papua New Guinea	Extant	Native	–	–
Peru	Extant	Native	–	–
Philippines	Extant	Native	–	–
Portugal	Extant	Native	–	–
Portugal -> Azores	Extant	Native	–	–
Portugal -> Portugal (mainland)	Extant	Native	–	–
Puerto Rico	Extant	Native	–	–
Réunion	Extant	Native	–	–
Saint Barthélemy	Extant	Native	–	–
Saint Helena, Ascension and Tristan da Cunha	Extant	Native	–	–
Saint Helena, Ascension and Tristan da Cunha -> Ascension	Extant	Native	–	–
Saint Kitts and Nevis	Presence Uncertain	Native	–	–
Saint Lucia	Presence Uncertain	Native	–	–
Saint Martin (French part)	Extant	Native	–	–
Saint Vincent and the Grenadines	Presence Uncertain	Native	–	–
Samoa	Presence Uncertain	Native	–	–
Sao Tome and Principe	Extant	Native	–	–
Senegal	Presence Uncertain	Native	–	–
Seychelles	Extant	Native	–	–
Sierra Leone	Presence Uncertain	Native	–	–
Singapore	Presence Uncertain	Native	–	–
Sint Maarten (Dutch part)	Extant	Native	–	–
Solomon Islands	Extant	Native	–	–
Somalia	Extant	Native	–	–
South Africa	Extant	Native	–	–
Spain	Extant	Native	–	–
Sri Lanka	Extant	Native	–	–
Suriname	Presence Uncertain	Native	–	–
Taiwan, Province of China	Extant	Native	–	–
Tanzania, United Republic of	Extant	Native	–	–
Thailand	Presence Uncertain	Native	–	–
Timor-Leste	Presence Uncertain	Native	–	–
Tokelau	Extant	Native	–	–
Tonga	Extant	Native	–	–
Trinidad and Tobago	Presence Uncertain	Native	–	–
Turks and Caicos Islands	Presence Uncertain	Native	–	–
Tuvalu	Presence Uncertain	Native	–	–
United Kingdom of Great Britain and Northern Ireland	Extant	Native	–	–
United States Minor Outlying Islands	Extant	Native	–	–
United States Minor Outlying Islands -> Midway Is.	Extant	Native	–	–
United States of America	Extant	Native	–	–
Uruguay	Extant	Native	–	–
Vanuatu	Extant	Native	–	–
Venezuela, Bolivarian Republic of	Extant	Native	–	–
Viet Nam	Extant	Native	–	–
Virgin Islands, British	Presence Uncertain	Native	–	–
Virgin Islands, U.S.	Presence Uncertain	Native	–	–
Wallis and Futuna	Extant	Native	–	–
Western Sahara	Extant	Native	–	–
Yemen	Extant	Native	–	–

Large Marine Ecosystems (LME) Occurrence 

Large Marine Ecosystems: (Not specified) 

FAO Area Occurrence 

	Presence	Origin	Formerly Bred	Seasonality
21. Atlantic – northwest	Extant	Native	–	–
27. Atlantic – northeast	Extant	Native	–	–
31. Atlantic – western central	Extant	Native	–	–
34. Atlantic – eastern central	Extant	Native	–	–
37. Mediterranean and Black Sea	Extant	Vagrant	–	–
41. Atlantic – southwest	Extant	Native	–	–
47. Atlantic – southeast	Extant	Native	–	–
51. Indian Ocean – western	Extant	Native	–	–
57. Indian Ocean – eastern	Extant	Native	–	–
61. Pacific – northwest	Extant	Native	–	–
71. Pacific – western central	Extant	Native	–	–
77. Pacific – eastern central	Extant	Native	–	–
81. Pacific – southwest	Extant	Native	–	–
87. Pacific – southeast	Extant	Native	–	–

Climate change

The specific effects of climate change on 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

M. densirostris is the most common species of its genus and is considered fairly common within tropical waters (Reeves et al. 2003), however, no abundance estimates are available for this species within the assessment region. In some regions such as off Hawaii both island associated and open ocean populations of Blainville’s beaked whales occur, further complicating assessments of abundance (Baird 2019). 

Population Information

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

Recent population genomic investigations have uncovered substantial structure within Blainville’s Beaked Whales, with animals being from the Atlantic and Indo-Pacific Ocean showing deep divergences (Carroll et al. 2021; Onoufriou et al. 2022). Moreover, further substructure was detected within each Ocean basin (Onoufriou et al. 2022), with two ESUs identified in the Indo-Pacific region (Central Pacific and southern Hemisphere) and two distinct subpopulations within the southern hemisphere ESU, of which animals around the assessment region form one. Unfortunately, no measure of effective population size (Ne) were reported; however, through reanalysis of the data, this metric should be obtainable.   

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

Mesoplodon species occur commonly in deep-waters and along continental slopes, where prey availability may be enhanced by the interactions between ocean currents and topography (MacLeod & Zuur 2005). Off the Bahamas for example, Blainville’s Beaked Whales showed a strong preference for areas with specific seabed aspects (northeast), gradients (68 to 296 m/km) and depths (136 to 1319 m) likely driven by high prey abundance associated with these areas (Allen et al. 2011). Habitat partitioning driven by age class or dominance hierarchy may also be present in this species in some parts of their range (Allen et al. 2011). Baird (2019) also suggests that sympatric Cuvier’s and Blainville’s Beaked Whales also partition their habitat to avoid direct competition between the species, with Cuvier’s beaked whales found in deeper waters and diving deeper than Blainville’s Beaked Whales. Beaked Whales are believed to be suction feeders (Heyning & Mead 1996), feeding predominantly on squid and deep-water fish. M. densirostris is no exception. Diving data from Hawaii suggest that Balinville’s Beaked Whales can dive for 83 minutes and to depths of 1599m (Baird 2019). During these long foraging dives individuals consume on average 25 small prey items including deepwater cephalopods and fish (Baird 2019). Sekiguchi et al. (1992) and Ross (1984) reported stomach contents containing the remains of Buttersnoek (Lepidopus caudatus) and lanternfish (Lampanyctus spp.). Off Hawaii, schools of between three and seven Blainville’s Beaked Whales were observed by Shallenberger (1981) while Baird (2019) observed group sizes of 1 to 11 (mean 3.8) individuals in the same population, with mean group sizes of 4.1 reported from the northern Bahamas (Allen et al. 2011). Baird (2019) suggests that groups primarily form for functional purposes such as predator avoidance or to provide mating opportunities, but that these social relationships are ephemeral in nature. 

IUCN Habitats Classification Scheme

Habitat	Season	Suitability	Major Importance?
10.1. Marine Oceanic -> Marine Oceanic – Epipelagic (0-200m)	–	Marginal	–
10.2. Marine Oceanic -> Marine Oceanic – Mesopelagic (200-1000m)	–	Suitable	Yes
10.3. Marine Oceanic -> Marine Oceanic – Bathypelagic (1000-4000m)	–	Marginal	–

Life History

Generation Length: Not specified 

Age at Maturity:  Female or unspecified: 9 years, Mead 1984

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): Females: 471 cm; Males: 473 cm, Mead 1984

Size at Birth (in cms): 261 cm

Gestation Time: Not specified 

Reproductive Periodicity: Not specified

Average Annual Fecundity or Litter Size: Not specified

Natural Mortality: Not specified 

Breeding Strategy

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, although some small-scale subsistence utilisation of Blainville’s Beaked Whale by artisanal fisheries has been recorded.  

Subsistence:	Rationale:	Local Commercial:	Further detail including information on economic value if available:
Yes	–	–	–

National Commercial Value: No 

International Commercial Value: No 

End Use	Subsistence	National	International	Other (please specify)
1. Food – human	true	–	–	–

Is there harvest from captive/cultivated sources of this species? (Not specified) 

Harvest Trend Comments: (Not specified) 

Threats

There appear to be no widely distributed major threats to beaked whales. The impact of potential threats are unknown but, considering that most Ziphiidae species are naturally rare, especially within the assessment region, they may have unsustainable impacts on local populations and further research is required. The main current threats for Blainville’s Beaked Whale are climate change, whaling, military sonar, vessel noise, entanglement, depredation, 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, most commonly Blainville’s and Cuvier’s beaked whales, have been attributed to seismic exploration and 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. Repeated exposure to high-intensity anthropogenic noise can also have sublethal effects on animals through cessation of foraging or abandonment of critical foraging habitat which can ultimately impact reproduction and overall survival (Baird 2019). 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). A dead adult Blainville’s Beaked Whale found on a beach in southern Brazil in 1993 was found to contain a bundle of blue plastic threads within its primary stomach chamber (Secchi & Zarzur 1999). Based on the lack of food and parasites within its stomach and gut, it is likely that this individual had not fed for some time.  Chemical pollution (POPs and heavy metals) may also impact beaked whales due to negative effects on reproduction and overall health (Feyrer et al. 2024).  
 
Accidental entanglement of beaked whales in fisheries is widespread, particularly in deep-water gillnets, although the number of recorded mortalities is not high. Entanglements involving at least 15 species of beaked whales have been documented globally (Feyrer et al. 2024). 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. Depredation of fish from fishing gear or nets has been reported for at least five species of beaked whales which may increase the incidence of entanglements, ingestion of inappropriate food items (hooks or line), ship strikes or injuries incurred due to negative interactions (retaliation) with fishers (Feyrer et al. 2024). 
 
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.  

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 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. 

Bibliography

Allen, B.M., Mead, J.G. and R.L. Brownell. 2011. Species review of Blainville’s beaked whale, Mesoplodon densirostris. IWC Scientific Committee documents SC/63/SM16. p. 18 (accessed on 14 March 2025). 

Anderson, R. C., Clark, R., Madsen, P. T., Johnson, C., Kiszka, J. and Breysse, O. 2006. Observations of Longman’s beaked whale (Indopacetus pacificus) in the Western Indian Ocean. Aquatic Mammals 32(2): 223-231. 

Baird, R.W. 2019. Behavior and ecology of not-so-social odontocetes: Cuvier’s and Blainville’s beaked whales. In: Würsig, B. (ed) Ethology and behavioral ecology of odontocetes. Springer, Cham, p 305– 329 

Baker AN. 1983. Whales and Dolphins of New Zealand and Australia. An Identification Guide. University Press, Wellington, Victoria. 

Balcomb, K. C. 1989. Baird’s beaked whale Berardius bairdii Stejneger, 1883: Arnoux’s beaked whale Berardius arnuxii Duvernoy, 1851. In: S. H. Ridgway and R. Harrison (eds), Handbook of marine mammals, Vol. 4: River dolphins and the larger toothed whales, pp. 261-288. Academic Press. 

Balcomb, K.C. and Claridge, D.E. 2001. A mass stranding of cetaceans caused by naval sonar in the Bahamas. Bahamas Journal of Science 8(2): 2-12. 

Barlow, J. 1999. Trackline detection probability for long-diving whales. In: G. W. Garner, S. C. Amstrup, J. L. Laake, B. J. F. Manley, L. L. McDonald and D. G. Robertson (eds), Marine mammal survey and assessment methods, pp. 209-221. Balkema Press, Netherlands. 

Barlow, J. 2006. Cetacean abundance in Hawaiian waters estimated from a summer/fall survey in 2002. Marine Mammal Science 22(2): 446-464. 

Barlow, J. and Gisiner, R. 2006. Mitigating, monitoring and assessing the effects of anthropogenic sound on beaked whales. Journal of Cetacean Research and Management 7(3): 239-250. 

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