Overview

Physeter macrocephalus – Linnaeus, 1758

ANIMALIA – CHORDATA – MAMMALIA – ARTIODACTYLA – PHYSETERIDAE – Physeter – macrocephalus 

Common Names: Sperm Whale, Spermacet Whale, Pot Whale, Cachelot (English), Potvis (Afrikaans), Ballena Esperma, Cachalote (Spanish; Castilian), Cachalot (French), Capodoglio (Italian), Gabdoll (Maltese), Kashalot (Albanian), Kaşalot (Turkish), Ulješura (Croatian), İspermeçet balinası (Turkish), φυσητήρας (fysitíras) (Greek, Modern (1453-)), ראשתן (roshtan) (Hebrew), عنبر (anbar) (Arabic)
Synonyms: Physeter catodon Linnaeus, 1758 

Species name changed to macrocephalus, based on priority rule  

Taxonomic Note: 
Although Physeter catodon is still occasionally used in the literature, P. macrocephalus is recommended (Rice 1989). Both names are listed on the same page of the original description by Linnaeus (1758), and priority is unclear. However, P. macrocephalus is preferable because it is used much more frequently, and this will support nomenclatural stability. 

Red List Status: VU – Vulnerable, A1d (IUCN version 3.1) 

Assessment Information

Assessors: Shabangu, F.^1,2, Purdon, J.^2,3 & da Silva, J.⁴ 

Reviewer: Smith, C.⁵ 

Institutions: ¹Department of Forestries, Fisheries and the Environment, ²The Whale Unit, University of Pretoria, ³TUT Nature Conservation, ⁴South African National Biodiversity Institute, ⁵Endangered Wildlife Trust 

Previous Assessors: Elwen, S., Findlay, K., Meyer, M., Oosthuizen, H. & Plön, S. 

Previous Reviewer: Child, M.F. 

Previous Contributor: Relton, C. 

Assessment Rationale

Although the population is recovering, commercial whaling in the Antarctic within the last three generations (90 years) reduced the global abundance of species significantly. As commercial whaling has ceased, the species is evaluated under the A1 criterion. Model results revealed a 6% probability for Endangered, a 54% probability of Vulnerable, and a 40% probability of Near Threatened. Thus, the species is listed as Vulnerable A1d based on historical decline in line with the global assessment. Circumpolar surveys estimate around 8,300 mature males, which is extrapolated to around 40,000 individuals in total. Within the assessment region, the historical depletion may have created a skewed sex ratio, which may make this species more vulnerable to minor threats. For example, systematic surveys from the Antarctic showed no significant population increase between 1978 and 1992. Modelling results corroborate the Sperm Whale’s slow recovery rate, where a small decrease in adult female survivorship could lead to a declining population. Ongoing loss of mature individuals from entanglement in fishing nets and plastic ingestion could be hindering population recovery in certain areas. Furthermore, marine noise pollution may be an emerging threat that could suppress population recovery, as this reduces the foraging and communication behaviour of the species. The effects should continue to be monitored. Overall, the overexploitation of Sperm Whales has ceased, and they usually remain fairly far from anthropogenic effects due to their deep-sea distribution, and the large-scale commercial fishing industry does not target major Sperm Whale food sources. However, given their historical depletion, their slow growth rate (possibly only 1% per year) and their modelled sensitivity to disturbance, current abundance and population trend estimates are urgently needed, and this species should be reassessed once such data are available.

Regional population effects: Sperm Whales are highly migratory and wide-ranging. There are no barriers to dispersal, thus 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: Shabangu F, Purdon J & da Silva JM. 2025. A conservation assessment of Physeter macrocephalus. 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 

Sperm whales have a broad geographic range (Rice 1989) and may be present in nearly every marine region from the tropics to high latitudes. Typically, they are located in deeper waters or along the continental slope, avoiding waters shallower than 300 m. Their geographic range also includes several enclosed or partially enclosed areas, including both the Mediterranean and Baltic Seas, the Sea of Okhotsk and the Gulf of Mexico. Their distributions vary according to sex and size, where males have been observed closer to inshore areas than females (Best 1999). Additionally, females and their young are often restricted in their range to regions between 40°N and 40°S, while males may migrate as far as 70°N and 70°S in summer, and larger males appear to extend further north or south than smaller individuals. Sperm Whales are known to travel substantial distances, with one individual reported to have covered a straight-line distance of 7,400 km (Ivashin 1967). Although some overlap in geographic distribution is known to occur between Northern and Southern Hemisphere stocks, populations are thought to be genetically isolated because seasonal breeding periods occur six months apart.

The International Whaling Commission (IWC) recognises nine Sperm Whale divisions for the Southern Hemisphere, which have been based more specifically on data available from commercial whaling, rather than actual biological factors (Donovan 1991). Although Sperm Whales migrate long distances, and exhibit low genetic differentiation between ocean basins (Lyrholm et al. 1999; Mesnick et al. 1999; Drouot et al. 2004a), some studies infer a high degree of geographic structure among populations across many regions (Bannister & Mitchell 1980; Kasuya & Miyashita 1988; Rendell & Whitehead 2003; Whitehead 2003). This is corroborated by recent molecular analyses that suggest females show site fidelity to coastal basins while males disperse widely for breeding (Engelhaupt et al. 2009). Within South African waters, Sperm Whales are present across the majority of the Exclusive Economic Zone (EEZ), frequently in deep waters off the west coast, and excluding shallow regions along the continental shelf. Records from Durban (30°S) and Donkergat (33°S) found that males and females reveal varied seasonality where large males were often caught in this region in spring, while juvenile males and females were more frequently caught earlier in winter. Passive acoustic monitoring data also show year-round presence of Sperm Whale clicks off the west coast of South Africa with presence peak in spring through summer (Shabangu and Andrew 2020). A recent distribution modelling study (Purdon et al. 2020a) indicated that sperm whales come closer to shore throughout the assessment area during winter, but still remaining off the shelf. In summer their distribution covers a wider area within the assessment area.  

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): 0 

Depth Upper Limit (in metres below sea level): ≥3000 

Depth Zone: Bathypelagic 

Map

Figure 1. Distribution records for Sperm Whale (Physeter macrocephalus) 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, Antarctic, Australasian, Indomalayan, Nearctic, Neotropical, Oceanian, Palearctic 

Occurrence 

Countries of Occurrence 

Country	Presence	Origin	Formerly Bred	Seasonality
Albania	Extant	Native	–	–
Algeria	Extant	Native	–	–
American Samoa	Presence Uncertain	Native	–	–
Angola	Extant	Native	–	–
Anguilla	Presence Uncertain	Native	–	–
Antarctica	Extant	Native	–	–
Antigua and Barbuda	Extant	Native	–	–
Argentina	Extant	Native	–	–
Aruba	Presence Uncertain	Native	–	–
Australia	Extant	Native	–	–
Bahamas	Extant	Native	–	–
Bangladesh	Extant	Native	–	–
Barbados	Extant	Native	–	–
Belgium	Extant	Native	–	–
Belize	Extant	Native	–	–
Benin	Extant	Native	–	–
Bermuda	Presence Uncertain	Native	–	–
Bonaire, Sint Eustatius and Saba	Extant	Native	–	–
Bosnia and Herzegovina	Presence Uncertain	Native	–	–
Brazil	Extant	Native	–	–
British Indian Ocean Territory	Presence Uncertain	Native	–	–
Brunei Darussalam	Extant	Native	–	–
Cabo Verde	Extant	Native	–	–
Cambodia	Presence Uncertain	Native	–	–
Cameroon	Extant	Native	–	–
Canada	Extant	Native	–	–
Cayman Islands	Presence Uncertain	Native	–	–
Chile	Extant	Native	–	–
China	Extant	Native	–	–
Christmas Island	Presence Uncertain	Native	–	–
Cocos (Keeling) Islands	Presence Uncertain	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	–	–
Croatia	Extant	Native	–	–
Curaçao	Extant	Native	–	–
Cyprus	Extant	Native	–	–
Côte d’Ivoire	Presence Uncertain	Native	–	–
Denmark	Extant	Native	–	–
Djibouti	Extant	Native	–	–
Dominica	Extant	Native	–	–
Dominican Republic	Extant	Native	–	–
Ecuador	Extant	Native	–	–
Egypt	Extant	Native	–	–
El Salvador	Extant	Native	–	–
Equatorial Guinea	Extant	Native	–	–
Eritrea	Presence Uncertain	Native	–	–
Falkland Islands (Malvinas)	Extant	Native	–	–
Faroe Islands	Extant	Native	–	–
Fiji	Extant	Native	–	–
France	Extant	Native	–	–
French Guiana	Presence Uncertain	Native	–	–
French Polynesia	Presence Uncertain	Native	–	–
French Southern Territories	Presence Uncertain	Native	–	–
Gabon	Extant	Native	–	–
Gambia	Extant	Native	–	–
Germany	Presence Uncertain	Native	–	–
Ghana	Extant	Native	–	–
Gibraltar	Extant	Native	–	–
Greece	Extant	Native	–	–
Greenland	Extant	Native	–	–
Grenada	Extant	Native	–	–
Guadeloupe	Presence Uncertain	Native	–	–
Guam	Presence Uncertain	Native	–	–
Guatemala	Extant	Native	–	–
Guinea	Extant	Native	–	–
Guinea-Bissau	Extant	Native	–	–
Guyana	Extant	Native	–	–
Haiti	Extant	Native	–	–
Honduras	Extant	Native	–	–
Hong Kong	Presence Uncertain	Native	–	–
Iceland	Extant	Native	–	–
India	Extant	Native	–	–
Indonesia	Extant	Native	–	–
Iran, Islamic Republic of	Extant	Native	–	–
Ireland	Extant	Native	–	–
Israel	Extant	Native	–	–
Italy	Extant	Native	–	–
Jamaica	Extant	Native	–	–
Japan	Extant	Native	–	–
Kenya	Extant	Native	–	–
Kiribati	Extant	Native	–	–
Korea, Democratic People’s Republic of	Extant	Native	–	–
Korea, Republic of	Extant	Native	–	–
Lebanon	Extant	Native	–	–
Liberia	Extant	Native	–	–
Libya	Extant	Native	–	–
Madagascar	Extant	Native	–	–
Malaysia	Extant	Native	–	–
Maldives	Extant	Native	–	–
Malta	Extant	Native	–	–
Marshall Islands	Extant	Native	–	–
Martinique	Presence Uncertain	Native	–	–
Mauritania	Extant	Native	–	–
Mauritius	Extant	Native	–	–
Mayotte	Presence Uncertain	Native	–	–
Mexico	Extant	Native	–	–
Micronesia, Federated States of	Extant	Native	–	–
Monaco	Extant	Native	–	–
Montenegro	Presence Uncertain	Native	–	–
Montserrat	Presence Uncertain	Native	–	–
Morocco	Extant	Native	–	–
Mozambique	Extant	Native	–	–
Myanmar	Presence Uncertain	Native	–	–
Namibia	Extant	Native	–	–
Nauru	Extant	Native	–	–
Netherlands	Extant	Native	–	–
New Caledonia	Presence Uncertain	Native	–	–
New Zealand	Extant	Native	–	–
Nicaragua	Extant	Native	–	–
Nigeria	Extant	Native	–	–
Niue	Extant	Native	–	–
Norfolk Island	Presence Uncertain	Native	–	–
Northern Mariana Islands	Presence Uncertain	Native	–	–
Norway	Extant	Native	–	–
Oman	Extant	Native	–	–
Pakistan	Extant	Native	–	–
Palau	Extant	Native	–	–
Palestine, State of	Presence Uncertain	Native	–	–
Panama	Extant	Native	–	–
Papua New Guinea	Extant	Native	–	–
Peru	Extant	Native	–	–
Philippines	Extant	Native	–	–
Pitcairn	Presence Uncertain	Native	–	–
Portugal	Extant	Native	–	–
Puerto Rico	Presence Uncertain	Native	–	–
Qatar	Presence Uncertain	Native	–	–
Russian Federation	Extant	Native	–	–
Réunion	Presence Uncertain	Native	–	–
Saint Barthélemy	Extant	Native	–	–
Saint Helena, Ascension and Tristan da Cunha	Extant	Native	–	–
Saint Kitts and Nevis	Extant	Native	–	–
Saint Lucia	Extant	Native	–	–
Saint Martin (French part)	Extant	Native	–	–
Saint Pierre and Miquelon	Presence Uncertain	Native	–	–
Saint Vincent and the Grenadines	Extant	Native	–	–
Samoa	Extant	Native	–	–
Sao Tome and Principe	Extant	Native	–	–
Saudi Arabia	Presence Uncertain	Native	–	–
Senegal	Extant	Native	–	–
Seychelles	Extant	Native	–	–
Sierra Leone	Extant	Native	–	–
Singapore	Extant	Native	–	–
Sint Maarten (Dutch part)	Extant	Native	–	–
Slovenia	Extant	Native	–	–
Solomon Islands	Extant	Native	–	–
Somalia	Extant	Native	–	–
South Africa	Extant	Native	–	–
South Georgia and the South Sandwich Islands	Presence Uncertain	Native	–	–
Spain	Extant	Native	–	–
Sri Lanka	Extant	Native	–	–
Sudan	Presence Uncertain	Native	–	–
Suriname	Extant	Native	–	–
Sweden	Presence Uncertain	Native	–	–
Syrian Arab Republic	Extant	Native	–	–
Taiwan, Province of China	Extant	Native	–	–
Tanzania, United Republic of	Extant	Native	–	–
Thailand	Extant	Native	–	–
Timor-Leste	Extant	Native	–	–
Togo	Extant	Native	–	–
Tokelau	Presence Uncertain	Native	–	–
Tonga	Extant	Native	–	–
Trinidad and Tobago	Extant	Native	–	–
Tunisia	Extant	Native	–	–
Turks and Caicos Islands	Presence Uncertain	Native	–	–
Tuvalu	Extant	Native	–	–
Türkiye	Extant	Native	–	–
United Arab Emirates	Presence Uncertain	Native	–	–
United Kingdom of Great Britain and Northern Ireland	Extant	Native	–	–
United States Minor Outlying Islands	Presence Uncertain	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	Presence Uncertain	Native	–	–
Western Sahara	Presence Uncertain	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	Native	–	–
41. Atlantic – southwest	Extant	Native	–	–
47. Atlantic – southeast	Extant	Native	–	–
48. Atlantic – Antarctic	Extant	Native	–	–
51. Indian Ocean – western	Extant	Native	–	–
57. Indian Ocean – eastern	Extant	Native	–	–
58. Indian Ocean – Antarctic	Extant	Native	–	–
61. Pacific – northwest	Extant	Native	–	–
67. Pacific – northeast	Extant	Native	–	–
71. Pacific – western central	Extant	Native	–	–
77. Pacific – eastern central	Extant	Native	–	–
81. Pacific – southwest	Extant	Native	–	–
87. Pacific – southeast	Extant	Native	–	–
88. Pacific – Antarctic	Extant	Native	–	–

Climate change

Sperm whales are ecosystem sentinels (Hazen et al. 2019) and can therefore indicate ecosystem change. Close monitoring of this species to determine distribution changes could highlight areas that are more susceptible to climate change. For example, a study by Posdaljian et al. (2022) showed that between the years of 2015 and 2019 in Baffin Bay of the Canadian Arctic, acoustic presence of sperm whales increased steadily. They related this increase to the minimum sea ice concentration each year. In this area their distribution is likely expanding, however in other areas this may not be the case. In New Zealand a study showed that under the worst-case scenario of climate change RCP 8.5 (where nothing is done to curb greenhouse gas emissions by 2100) 61% of sperm whale habitat would be lost. Climate change poses a threat to sperm whales due to their longevity and sensitivity to their prey species’ distribution and abundance (Peters et al. 2022) and could therefore impact their recovery from whaling.  

In South Africa little has been done to determine the effects of climate change on sperm whales. Purdon et al. (2020b) conducted a study on the anthropogenic effects on cetacean species richness. They found that in the assessment area, climate change stressors which include increasing sea surface temperature, ocean acidification and rising sea levels pose high risks to species richness. It was also noted that ocean acidification and sea level rise increased throughout the assessment area with the highest trends along the west and south coast, areas where sperm whale presence is high. Ocean acidification may affect phytoplankton and zooplankton affecting top marine predators (Simmonds and Isaac, 2007) like sperm whales. Future research should include modelling the effects of climate change on sperm whale distribution as well as their prey’s distribution.  

Population information

Using historical trajectories, an abundance model for global Sperm Whale populations was developed to estimate the population decline between 1700 and 2022 (Whitehead and Shin 2022). This model includes only the threat of legal commercial whaling and does not consider any other anthropogenic threats to this species, such as ship strikes, illegal whaling in the North Pacific and Antarctica, climate change, pollution, entanglement in fishing gear, or the persistent effects of social disruption and sexually skewed population structure. These factors may limit population recovery in many areas. Estimates of trends in the post-whaling era (from 1982) suggest that sperm whale populations not facing much human impact are recovering slowly, but populations may be declining in areas with substantial anthropogenic footprint (Whitehead and Shin 2022). Although there is uncertainty, the model estimates a global pre-exploitation (1710) population of 1.9 million Sperm Whales declining to 840,000 in 2022 (57% decline) with most of this decline occurring during the period of heavy industrialized whaling between 1950-1975.  The three generation (1940-2022) decline is estimated as 48%. Thus, the species remains close to Vulnerable status under the A1 criterion.  

Two major global Sperm whaling operations were driven by the high commercial value attached to this species: the primitive “open-boat” hunt from 1712–1920 (Best 1983), and the modern whaling expeditions from 1910–1988 (Tønnessen & Johnsen 1982). Modern whaling operations did not impact all Sperm Whale populations. For example, populations in the western North Atlantic remain at reasonably high densities and show evidence of successful reproduction (Gordon et al. 1998). After the decline of other large rorqual species and the invention of new uses for Sperm Whale oil, commercial whaling of this species was intensified until 1964, when an annual peak of 29,255 individuals were caught. Limits imposed by the IWC after 1968 coincided with the development of synthetic alternatives for Sperm Whale oil, resulting in a decline in Sperm whaling efforts. Commercial Sperm whaling is currently prohibited by the IWC. Under special permit, only one Sperm Whale was recorded as caught in the 2009/10 season by a Japanese whaling vessel in the North Pacific (IWC unpubl. data). Although, the effect on the Sperm Whale stocks by small-scale recent operations is negligible, the value of these activities is severely questioned.

There is some concern that a few locations are still in decline, and there is no clear quantitative evidence suggesting that the global population has shown a recovery since large-scale whaling ceased in 1980 (Taylor et al. 2008). There is also no evidence to the contrary. Future population assessments are required to address the doubt surrounding the recovery of this species. Within the assessment region, we assume that the population is at the depleted level suggested by the global assessment, although evidence from the circumpolar surveys indicates that the population is recovering (IWC unpubl. data). The historical depletion may have created a skewed sex ratio, which may make this species more vulnerable to minor threats (for example, plastic pollution, ship strikes, entanglements). While the Antarctic population should have repopulated from less heavily exploited breeding populations at lower latitudes following the end of large-scale commercial whaling (Taylor et al. 2008), systematic surveys of Sperm Whales in the Antarctic showed no substantial or statistically significant increase between 1978 and 1992 (Branch & Butterworth 2001). We infer the population trend to be stable but current surveys are required to assess population trends. Corroborating the empirically estimated slow recovery rate, a recent population model revealed that Sperm Whale populations grow slowly and are potentially sensitive to survivorship rates of adult females, where a slight decline in survivorship could lead to a declining population (Chiquet et al. 2013).  

Continuing decline in mature individuals?	Qualifier	Justification
No	–	–

Current population trend: Stable  

Number of mature individuals in population: c. 8,300 from circumpolar surveys.  

Number of mature individuals in largest subpopulation: Unknown  

Number of subpopulations: Unknown  

Severely fragmented: No 

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

Continuing decline in number of subpopulations: (Not specified) 

All individuals in one subpopulation: (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

A population genetic study examining the structure and diversity of sperm whales across its range, and specifically within South Africa, revealed a single population throughout the assessment region, and this population differs genetically to those in the Atlantic and Indo-Pacific (Neveceralova et al. 2022). The African population (i.e., including Namibia) was also found to possess the most genetic variation; however, there was evidence of increased inbreeding over the past decade.

Based on this information, the proportion of populations maintained indicator can be calculated as 1.0 (1 of 1 populations maintained); however, because there are no known population size estimates for the region and contemporary effective population size (Ne) has not been calculated, the Ne 500 indicator cannot be estimated. Should updated count data be acquired, caution should be taken in estimating Ne given the observed levels of inbreeding. It is rather advisable to quantify Ne based on available genetic data.

Habitats and ecology

With the exception of the Black Sea and probably the Red Sea, sperm whales occur within all major marine water bodies deeper than 1,000 m including areas covered by ice sheets (Rice 1989; Whitehead 2003, Giorli and Pinkerton 2023). They are predominantly located in deeper waters of the open sea. However, they (especially males) may occasionally frequent shallower waters of the western North Atlantic (Scott & Sadove 1997). Females and young are most commonly limited to waters exhibiting sea surface temperatures greater than 15 °C (Rice 1989); and at latitudes lower than 40°N and 40°S. Their abundance and habitat selection usually increases with primary productivity (Jaquet et al. 1996; Rendell et al. 2004).

Sperm Whales are sexually dimorphic. Males may reach lengths of up to 18.3 m, while mature females may have a mass three times less than that of mature males, reaching lengths of 12.5 m. A 13.3 m male Sperm Whale weighed on a railway loading truck in Durban was 31,450 kg (Gambell 1970), but the heaviest recorded Sperm Whales included a male of 18.1 m at 57,000 kg and a female of 11.0 m at 24,000 kg. Sperm Whales have a substantial ecological footprint, and may consume roughly the same amount of biomass of marine resources as humans (Whitehead 2003).

Mesopelagic squid form the principal food source for Sperm Whales; however, in certain regions bottom dwelling fish are also commonly taken (Roe 1969). In South African waters, squid with an average weight of 0.5– 0.6 kg are usually consumed, while in the Antarctic, much larger squid (about 7.0 kg) are commonly preyed upon. The largest recorded squid found in the belly of a Sperm Whale was a Giant Squid (Architeuthis spp.) weighing 184 kg and 4.94 m long. Additional Sperm Whale food sources documented off the west coast of South Africa include crabs and tunicates (most commonly eaten by males), mysids and oilfish (more frequently eaten by females), and rays, angler fish and lancet fish (only eaten by males) (Best 1999). Adult males and females are thought to consume approximately 2% and 3% of their body mass per day, respectively. Bottom-dwelling sharks found in the stomach of a Sperm Whale collected in Durban suggest that the whale would have dived over 3,000 m deep.

The breeding season of Sperm Whales in the Southern Hemisphere peaks between October and December.  

Females usually produce calves every three or five years; however, this duration increases with age (Rice 1989). Following a gestation period of 15–16 months, one calf (about 4 m in length) is born. Solid food is consumed before the calf reaches a year old; however, the stomachs of some individuals still contained evidence of milk at ages of 7.5 years and 13 years for females and males, respectively. Sexual maturity is reached at an age of 7–13 years (lengths of 8.5 m) for females, and at around 20 years (lengths of 12.5 m) for males; however, males only reach the status of a “breeding bull” once they are around 25 years old (lengths of 13.7 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 mysticete whales may be used to investigate broad-scale shifts in ecosystems (Moore 2008). Sperm Whales are also important reservoirs of, and vectors for, nutrients (Roman et al. 2014), thus influencing oceanic ecosystem functioning. A Sperm Whale is the main antagonist (or protagonist, depending on your point of view) in the classic novel Moby Dick by Herman Melville. 

IUCN Habitats Classification Scheme 

Habitat	Season	Suitability	Major Importance?
9.1. Marine Neritic -> Marine Neritic – Pelagic	–	Suitable	Yes
10.1. Marine Oceanic -> Marine Oceanic – Epipelagic (0-200m)	–	Suitable	Yes
10.2. Marine Oceanic -> Marine Oceanic – Mesopelagic (200-1000m)	–	Suitable	Yes

Life History 

Generation Length	Justification	Data Quality
27.3	–	–

Age at Maturity: Female or unspecified: 7–13 years 

Age at Maturity: Male: 20 years  

Size at Maturity (in cms): Female: 850 

Size at Maturity (in cms): Male: 1250 

Longevity: 60-70 years 

Average Reproductive Age: 9-10 years 

Maximum Size (in cms): 2,000 

Size at Birth (in cms): 400 

Gestation Time: 15–16 months 

Reproductive Periodicity: 5-7 years 

Average Annual Fecundity or Litter Size: One calf 

Natural Mortality: 0.05 to 0.09 per year 

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: Daily movement 

Congregatory: Yes, up to 50 individuals 

Systems 

System: Marine 

General Use and Trade Information

Extensive commercial Sperm whaling has ceased, however, small-scale hunting for Sperm Whales continues in Japan and Indonesia. Under the IWC’s Special Permit, 10 individuals are taken per annum by Japanese whaling fleets (Clapham et al. 2003). During the whaling era, sperm whale blubber was used for products such as lamp oil, margarine, cooking oil, candles, soaps, and cosmetics, while whale meat was sold for animal feed and fertilisers. 

Subsistence:	Rationale:	Local Commercial:	Further detail including information on economic value if available:
No	–	–	–

National Commercial Value: No 

International Commercial Value: No 

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

Is there harvest from captive/cultivated sources of this species? No 

Harvest Trend Comments: (Not specified) 

Threats

Commercial whaling, historically the most substantial threat to the livelihood of this species, has ceased. Nonetheless, a range of additional factors threaten the remaining diminished populations of Sperm Whales. Considering that Sperm Whales are a large-scale migrating species, threats affecting this species in other areas of the world may impact populations that frequent the waters around South Africa, particularly those in the Atlantic, Indian and Southern Oceans. Similarly, population recovery is hindered by slow growth rates, possibly c. 1% per year (Whitehead 2002).

Similar to other cetaceans, Sperm Whales are vulnerable to entanglement in fishing gear, specifically gillnets, across a range of areas. This is particularly problematic in the Mediterranean Sea where Sperm Whales were one of the most commonly recorded non-target species caught in driftnets (Northridge 1991) before they were banned in 1990. Since 1990, illegal driftnet fisheries still occur in the Mediterranean but the frequency of Sperm Whale entanglements has declined considerably (Drouot et al. 2004b). Other cases of Sperm Whale entanglements have been recorded in Ecuador (Haase & Félix 1994) and California (Barlow & Cameron 2003), but are also considered to be a minor threat to this species within the assessment region. Although occasional catches in small scale gillnet fisheries are not currently expected to have a large effect on the global population, it is likely there are many more cases of Sperm Whale entanglements in unregulated driftnet fisheries in deeper waters, which are not recorded.

Occasionally, Sperm Whales engage in an activity known as “depredation”, when they actively remove fish from fishing gear (most commonly from demersal long-lines). This appears to be an increasing and risky phenomenon, which may result in entanglements, injury, death (Hucke-Gaete et al. 2004), and hostility from fishermen (including shooting of Sperm Whales) (Donoghue et al. 2003). It has been documented in a number of marine regions across the globe, including the North Atlantic, Chile, southeast Alaska, South Georgia, as well as other Southern Ocean islands and waters within the assessment region (Meÿer et al. 2011). In the Prince Edwards Islands (south of South Africa), Sperm Whales have been known to remove Patagonian Toothfish (Dissostichus eleginoides) from longline fishing vessels, which occasionally results in the illegal use of dynamite or thunder flashes to deter Sperm Whales (Ashford et al. 1996; Kock et al. 2006).

The sensitivity of Sperm Whales to noise is largely unconfirmed, where studies have shown contrasting evidence of high sensitivities (Watkins et al. 1985; Bowles et al. 1994) versus little to no effects on the species (Madsen & Møhl 2000; Madsen et al. 2002). There is a lack of research investigating the long-term effects of noise, sonar and seismic surveys on Sperm Whales, and, as yet, no mortality has been observed as a result of these disturbances. Off the west coast of South Africa, Sperm Whale clicks are masked by both high and low frequency underwater noise produced by marine traffic (Shabangu et al. 2022). On the other hand, this possible threat is increasing globally and thus the sensitivity of Sperm Whales to noise should be treated with caution.

Sexually-skewed whaling efforts may have long lasting effects on the reproductive rates (Whitehead 2003) and complex social cohesion of certain stocks, including those of the assessment region (Best 1979; Clarke et al. 1980; Whitehead et al. 1997); however, over time this inequality is likely to correct itself automatically. The population recovery and growth of Sperm Whales is fairly low, in fact, the maximum rate of increase is predicted to be around 1% per annum (Whitehead 2002). Population recovery since the end of commercial whaling, although inferred, remains purely theoretical for this species. Additionally, the severely depleted population of large, mature whales in the high latitudes of the Antarctic was assumed to have recovered from lower latitude areas where Sperm Whales were less heavily exploited following the end of commercial whaling. Contrastingly though, systematic surveys conducted for this species in the Antarctic did not reveal any significant increase between 1978 and 1992 (Branch & Butterworth 2001).

Collisions with ships impact Sperm Whales at a more regional scale, and have been specifically documented off the Canary Islands (André & Potter 2000) and in the Mediterranean (Pesante et al. 2002). Sperm Whales were listed as the most affected species by ship strikes near the island of Tenerife (Canary Islands), representing 48.8% of the total collision cases. Sperm whales are susceptible to ship strikes due their large bodies and the prolonged periods that they spend above water. In the assessment area, according to MRI unpublished data there has only been one sperm whale stranded whose death was attributed to a ship strike in 1999. Shipping pressure is high in the assessment area and overlaps with 87.40 % of predicted sperm whale distribution. This high level of overlap indicates that there are possibly many more undocumented deaths of sperm whales caused by ship strikes in the assessment area. This is probably due to these high-risk areas for ship strikes occurring offshore on the shelf edge, especially along the west coast.

The ingestion of marine debris, particularly plastic, is also known to be an increasing threat to this species (Viale et al. 1992; Simmonds 2011; de Stephanis et al. 2013). In 2008, the stomachs of two Sperm Whales stranded on the coast of California were found to contain substantial quantities of plastic debris, fishing net scraps and rope (Jacobsen et al. 2010). Gastric impaction as a result of this ingested debris was the most probable cause of death for both individuals (Jacobsen et al. 2010). Walker and Coe (1990) found that Sperm Whales are primarily affected by problems associated with the ingestion of marine debris, and this may cause a specific threat within the assessment region. Sperm Whale tissues also have high levels of some contaminants (O’Shea 1999; Nielsen et al. 2000), but it is uncertain whether this has an effect on the population level. 

Current habitat trend: Declining in quality due to pollution and climate change (MacLeod 2009). 

Conservation

The major historic threat to Sperm Whales (commercial whaling) has largely ceased. Thus, this species seems relatively secure from this threat in the short and medium term. Sperm Whales largely avoid anthropogenic effects, as they are mostly located in deeper waters away from the coastline. Additionally, much of this species’ food resources are safe from overexploitation by humans, as they feed predominantly on deep-water squid and fish in mesopelagic and benthic-pelagic habitats (Clarke 1977). This species is also listed on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and Appendices I and II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS).

In order to reduce ship strikes, determining the distribution and population estimations of Sperm Whales in areas of high vessel traffic is required. Additionally, high speed vessels may require dedicated on-board observers in order to detect the presence of Sperm Whales and other cetaceans along the trajectory of the vessel. Finally, detailed on-board monitoring reports of cetacean collisions are essential to assess the severity of this threat to cetacean populations within the assessment region.

There have been a number of legislative interventions to limit marine pollution. A key intervention is the 1978 Protocol to the International Convention for the Prevention of Pollution from Ships (MARPOL), which acknowledges that ships add a significant and manageable quantity of pollution into marine environments (Lentz 1987). Annex V of MARPOL aims to “restrict at sea discharge of garbage and bans at sea disposal of plastics and other synthetic materials such as ropes, fishing nets, and plastic garbage bags with limited exceptions”. Nevertheless, this legislation is largely ignored and Clarke (1977) estimated that 6.5 million tons of plastic is discarded into the ocean each year. Enforcement and international cooperation is essential to ensure that all marine vessels comply with the Annex V policy.

Education and community involvement is also a powerful tool with which to approach the threat of marine (particularly plastic) pollution. Considering that land-based pollution usually ends up in the ocean, awareness, education and terrestrial-based action is often more effective in mitigating the problem compared to the development of addition legislative policies (for example, Ross & Swanson 1994). 

Recommendations for managers and practitioners: 

• Systematic monitoring: design and implement a monitoring programme (acoustic and sightings) that can detect population size and trends. For example, by using the recently developed single nucleotide polymorphism markers (Morin et al. 2007). 
• Develop best practice guidelines for seismic surveys and enforce regulations. 

Research priorities: 

• Population size and trends. Given the long and deep diving behaviour of male Sperm Whales, the global estimate is almost certain to be an underestimate, as it is based on a sighting survey. 
• Effects of marine noise pollution on Sperm Whale populations. 
• Understanding the effects of minor threats (pollution, ship strikes, entanglements etc.) to this species, as well as the rates and trends associated with population recovery. 
• Conduct more acoustic surveys for sperm whale detections in the assessment area. Information from Posdaljin et al. (2022) study indicates that acoustic detections for sperm whales obtain more information than visual sightings. 

Encouraged citizen actions: 

• Whale-watching operators could contribute to photo ID catalogues and behavioural observations. 
• Report strandings to relevant authorities. 
• Participate as volunteers in Sperm Whale research projects. 
• Avoid using plastic bags, participate in beach and river clean-up initiatives, and raise awareness of the environmental threats associated with marine and terrestrial litter.  

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