Cuvier’s beaked whale
CUVIER’S BEAKED WHALE
Scientific name: Ziphius cavirostris
Distribution within the Mediterranean:
Conservation status in the Mediterranean:
Conservation status in the world:
7 metres in adults; between 2,3 and 2,7 metres at birth
Can be confused with:
|Individual identification characteristics:
The Cuvier’s beaked whale has a robust, compact but long body, which is characteristic of the family Ziphiidae. Neither the beak nor the melon are distinct, although the latter may be bigger and bulbous in adult males. The mouthline is rather curved. As with other species in the family, the Cuvvier’s beaked whale has two V-shaped throat grooves. Another distinctive feature of the species is a slight concavity on the top of the head, which is easier to detect in larger individuals. The dorsal fin is falcate, small and set quite far back, about two-thirds of the way back from the snout tip. Flukes are large and don’t always show a central notch. Flippers are rather small and can be hidden in lateral depressions called flipper pockets, in order to ensure more hydrodynamic swimming.
The Cuvier’s beaked whale is probably the species of cetacean with the highest variety of body coloration, which ranges from dark grey (mainly in adult males) to reddish brown (mainly in females). They can have two lighter areas around the head and on the belly. The head and part of the back may be completely white in adults. Eyes are surrounded by a dark pigmentation. Older individuals show more lineal, circular and oval scars, which may be caused by small sharks or lampreys.
Cuvier’s beaked whales only have two conic, forward pointing teeth in the anterior part of the lower jaw. They are only visible in adult males and in the larger individuals, in which the teeth can be seen outside of the mouth.
There are no significant differences between males and females. Maximum length is around 7 metres and maximum weight is around 3.000 kg. Newborns measure between 2,3 and 2,7 metres and weigh between 250 and 300 kg.
DISTRIBUTION AND MIGRATORY PATTERNS WITHIN THE MEDITERRANEAN SEA
The Cuvier’s beaked whale is the species of the Ziphiidae family with the most cosmopolitan distribution. It can be found in all seas and oceans of the world , from the temperate and warm equatorial areas to the cooler waters of higher latitudes but it is not present in very high latitude waters around the poles of either the northern or southern hemispheres. A clear preference is shown for waters far from the coast. They have also been found in many semi-closed and closed seas such as the Okhotsk Sea, the Gulf of California, the Gulf of Mexico, the Caribbean or the Mediterranean Sea. (Jefferson et al., 2008; Taylor et al., 2008 & Perrin et al., 2009).
In the Mediterranean Sea the exact distribution is unknown and most data has come from individual animals that were found stranded. It is believed to be common to both the eastern and western sides of the basin, although it has been thought that the four main areas where the animal can be found are the Ligurian Sea (especially the east), the Tyrrhenian Sea, the eastern Alboran Sea and North west Aegean Sea. The Balearic Sea and areas south of the Adriatic Sea could also be favorable to the species (Reeves and Notarbartolo di Sciara, 2006; Podestà et al., 2006; Holcer et al., 2007; Gannier and Epinat, 2008 & Gannier, 2011).
HABITAT AND FEEDING
The Cuvier’s beaked whale is a pelagic animal that inhabits areas with a marked bottom topography, for example areas with submarine canyons and escarpments. It is not often found in shallow surface waters or in waters above abyssal plains. It shows a preference for waters with depths of more than 500 to 600 metres, generally above 1000 metres with steep slopes, such as those found in submarine canyons or on the continental slope (Cañadas et al., 2002; Frantzis et al., 2003; Reeves and Notarbartolo di Sciara 2006; Azzellino et al., 2008; Gannier and Espinat, 2008 & Smith, 2010).
It is believed that the main prey of the Cuvier’s Beaked whale is squid, although few studies have been done on this topic. In different parts of the world it has been found to feed mostly on oceanic squid, especially from the Histioteuthidae, Cranchiidae and/or Gonatidae families. Alternatively, the Beaked whale also feeds on crustaceans or fish, but to a much lesser extent (Fiscus, 1997; Santos et al., 2001; MacLeod et al., 2003 & Smith, 2010).
REPRODUCTION AND LIFE HISTORY
There is not much known about the reproductive cycle of the Cuvier’s beaked whale owed to the difficulty of studying this animal. It is known that females reach sexual maturity when they measure approximately 5.8 metres, whilst males reach it at approximately 5.5 metres in length. Although there are no studies on the longevity of this species, it is believed that the maximum age for males is 36 years and for females is 30 years (Perrin et al., 2009).
ECOLOGY, BEHAVIOUR AND IDENTIFICATION
The difficulty in studying this animal has meant that there is not much information about their ecology, social structure or behavior. However, in recent years, several studies have been done that have allowed us to begin to understand this species a little better.
In different parts of the world, small groups of individuals of between 1 to 15 animals have been spotted, but these groups can reaach up to 26 animals. The average group size is between 2.3 and 3.8 individuals, depending on the area or time of year (Carwardine, 2004; Baird et al., 2006; MacLeod and D’Amico, 2006; McSweeney et al., 2007 & Falcone et al., 2009). Sometimes, solitary older males can be spotted.
The Cuvier’s Beaked whale is probably one of the species of marine mammals most capable of completing long and deep feeding dives, reaching almost 1,900 metres in depth (Tyack et al., 2006). It appears that this species has three different types of dives (Baird et al., 2006):
- Dives between breaths: very shallow dives (2-3 metres) of between 3-15 seconds in length, which occur in longer periods of time between deeper dives.
- Deep, long lasting dives: dives of more than 50 minutes reaching depths of more than 1,000 metres. On average they complete one of these deep dives every two hours. It is believed that these dives are related to feeding behaviors.
- Intermediate length dives: dives are between 20-30 minutes in length and down to intermediate depths of between 300-570 metres. 1 to 3 of these dives can be made in the time between the deep dives.
The feeding cycle takes about two hours and consists of a deep dive (from the 2nd category) and an interval between deep dives. During this interval, shallow (1st category) and intermediate (3rd category) dives are recorded. Thanks to information gained from sound recordings, it has been seen that during the deep dives, the beaked whale exhibits a lot of echolocation beginning at around 400-500 metres depth, which then intensifies between 500-1,000 metres in the bathypelagic and mesopelagic zones, where it is believed that their main prey is concentrated (Tyack et al., 2006).
In general this species tends to avoid boats and rarely jumps out of the water, which makes it more difficult to spot and recognise. At sea the Cuvier’s beaked whale can be confused with other species of the Ziphiidae family such as the Blainville’s beaked whale (Mesoplodon densirostris) or the Gervais’ beaked whale (Mesoplodon europaeus), but these two species are not as common in the Mediterranean Sea and there are certain other characteristics that allow us to differentiate the two species from the Cuvier’s Beaked Whale (Shirihai and Jarret, 2006 & IUCN 2012):
- A more robust body of medium size that is usually brownish and lighter than the other two species.
- A more rounded head with a white face and a shorter snout. Adult males present with two teeth in the front that protrude from the mouth.
- Larger individuals may have scars all over their bodies, probably due to interactions with other individuals of the same species.
INDIVIDUAL IDENTIFICATION CHARACTERISTICS
Despite the difficulty in studying the Cuvier’s Beaked Whale, different characteristics have allowed for the identification of individuals. In some cases, resighting rates reach up to 40%. Like with other cetaceans, we must look for permanent marks or scars that remain stable over time and which allow us to recognise these individuals every time we spot them. These characteristics include (McSweeney et al., 2007):
Dorsal fin: The shape of the fin as well as the presence of absence of notches along the posterior margin are used.
Colouration patterns: The general colouration of the Cuvier’s Beaked whale is highly variable among individuals and age groups. Adult males tend to have large white areas, for example along the dorsal part of the body. These differences are useful in distinguishing specific individuals.
Injuries or wounds: Many individuals exhibit a large number of body wounds that remain more or less stable over time. Those wounds that are found close to the dorsal fin or dorsal areas of the body can be used to recognise individual animals.
CONSERVATION STATUS AND MAIN THREATS
Despite the difficulty in studying this species, the Cuvier’s Beaked Whale is believed to have a worldwide population of more than 100,000 individuals (Barlow, 2006a & Barlow et al., 2006b). The area with the highest number of individuals is the North Pacific which is believed to have approximately 90,725 individuals, followed by the eastern tropical Pacific with approximately 20,000 individuals and the waters around Hawai’i with 15,242 animals. Other areas such as off the west coast of the North America and the Atlantic Ocean have a lower number of individuals. Because they are probably the most abundant of all the beaked whales with a very large geographical distribution, the International Union for Conservation of Nature (IUCN) has classified the Cuvier’s Beaked Whale globally under the status of “Least Concern”. In the Mediterranean there isn’t sufficient information on the abundance of this species. Presently there are only two studies that have estimated their population in the area around Genoa and also in the North Alboran Sea. Currently there are some studies that are being conducted that may be able to provide valuable information. Precisely because of this lack of information, the IUCN has classified the Cuvier’s Beaked Whale as under the status of “data deficient” in the Mediterranean. The principal threats that affect this species are:
- By catch: Although this does not affect this species as much as it does other species of Cetaceans in the Mediterranean, the Cuvier’s Beaked Whale has also been a victim of driftnets (Reeves and Notarbartolo di Sciara, 2006).
- Pollution: The main prey of the Cuvier’s Beaked Whale is squid. Whilst studying their diet, many individuals have been found with a large concentration of plastic in their stomachs which may have been confused for squid (Reeves and Notarbartolo di Sciara, 2006).
- Noise Pollution: Beaked whales are in general animals that base their feeding on deep dives, using echolocation to locate their prey. Over the last few decades there has been an increase in underwater noise that could seriously affect this species, possibly even leading to the death of some individuals. Some massive stranding events that have occurred around the world have been associated with military exercises involving the emission of low frequency and medium frequency sounds: The Canary Islands in February 1985, 3 more individuals in November 1988, 1 individual in June and 3 in December 1991, and 9 individuals in September 2002 (Martín et al., 2004 & Fernández et al., 2005); 12 individuals stranded in Greece in May 1996 (Frantzis, 1998 & 2004a); 3 individuals in Madeira in May 2000 (Freitas, 2004); 9 animals in the Bahamas in March 2000 (Balcomb and Claridge, 2001) and 2 individuals in the Gulf of California in September in 2002 (Cox et al., 2006). All these strandings occurred during or shortly after military exercises in the area. In addition, necroposies revealed that the stranded individuals were apparently healthy, had fed recently and did not show signs of illness or infection (Fernández et al., 2005). The exact causes of these strandings are unknown but several hypotheses have been put forward (Cox et al., 2006):
- Behavioural change in response to noise emission: One possible response to the emission of underwater noise is a change in behaviour which leads the animals to swim in shallower waters, closer to the coast, from which they are later unable to return from. This can lead to strandings or death from hyperthermia or stress.
- Behavioural change resulting in tissue damage: In this case, behavioural changes result in physiological changes as well that can cause damage at a histological level. Vigorous swimming and an interuption to feeding based on echolocation have been observed (DeRuiter et al., 2013) or changes to dive profiles. A change in these behaviours could lead to the formation of gas bubbles that could damage tissues during decompression, resulting in gas or fat embolism syndrome (Fernández et al., 2005 & DeRuiter et al., 2013). These embolisms have been seen to cause cardiovascular and respiratory disorders, pain and disorientation (Fernández et al., 2005).
- Physiological change resulting in a behavioural change: In many cases of massive strandings of the Cuvier’s Beaked Whales, the whales were found with internal bleeding, especially in the area around the eyes, oral cavity, and the acoustic canals of the jaw (Fernández, 2004 & Fernández et al., 2005). This bleeding could have been caused by the development of gas bubbles in the tissues (Fernández et al., 2004). In addition, exposure to noise could also provoke a vestibular response, affecting the peripheral vestibular system of the auditory apparatus, causing disorientation (Cox et al., 2006).
- Tissue damange as a result to noise exposure: Underwater noise can cause direct damage to tissues, causing bubble development, which can cause small histological injuries. However we have seen some cases where these injuries have led to stranding and/or the death of individuals (Cox et al., 2006).
Exposure to sound could also lead to an alteration of population structure or to the geographical distribution of the Cuvier’s Beaked whale population. After the massive stranding in the Bahamas, a research group that had spent 9 years studying the local population were unable to resight any of the previously identified individuals. It isn’t clear it this is because the identified individuals had died or if they had left the study area (Balcomb and Claridge, 2001).
The pelagic nature of this species has surely made it less vulnerable to the human activity that is concentrated along coastlines and that is usually most invasive to cetaceans (fisheries, tourism, etc.) In the Mediterranean Sea, the existence of the Pelagos Sanctuary in the Ligurian Sea and the recent designation of the marine sanctuary in the Alboran Sea, two important areas of distribution of the species, should encourage the preservation of this species.
The Cuvier’s Beaked whale is protected by various international conventions such as Appendix II of the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES) and the Agreement on the Conservation of Cetaceans of the Black Sea and the Mediterranean adjacent Atlantic area (ACCOBAMS). The scientific committee of the latter group recommends care or to completely avoid the production of underwater sounds in those areas frequented by the species or in areas where whales often concentrate.
AZZELLINO, A., GASPARI, S., AIROLDI, S. & NANI, B. 2008. Habitat use and preferences of cetaceans along the continental slope and the adjacent pelagic waters in the Ligurian Sea. Deep-Sea Research. 55:296-323
BAIRD, R. W.; WEBSTER, D. L., MCSWEENEY, D. J., LIGON, A. D., SCHORR, G. S. & BARLOW, J. 2006. Diving behaviour of Cuvier’s beaked (Ziphius cavirostris) and Blainville’s (Mesoplodon densirostris) beaked whales in Hawai’i. Canadian Journal of Zoology. 84:1120-1128
BALCOMB, K. C. III & 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. 2006a. Cetaceans abundance in Hawaiian waters estimated from a summer/fall survey in 2002. Marine Mammal Science 22(2):446-464
BARLOW, J., FERGUSON, M. C., PERRIN, W. F., BALLANCE, L., GERRODETTE, T., JOYCE, G., MACLEOD, C. D., MULLIN, K., PALKA, D. L. & WARING, G. 2006b. Abundance and densities of beaked and bottlenose whales (family Ziphiidae). Journal of Cetacean Research and Management. 7(3):263-270
CAÑADAS, A., SAGARMINAGA, R. & GARCÍA-TISCAR S. 2002. Cetacean distribution related with depth and slope in the Mediterranean waters of southern Spain. Deep-Sea Research. 49:2053-2073
CARWARDINE, M. 2004. Ballenas delfines y marsopas. Ediciones Omega. Barcelona. 2ª reimpresión
COX, T. M., RAGEN, T. J., READ, A. J., VOS, E., BAIRD, R. W., BALCOMB, K., BARLOW, J., CALDWELL, J., CRANFORD, T., CRUM, L., D’AMICO, A., D’SPAIN, G., FERNANDEZ, A., FINNERAN, J., GENTRY, R., GERTH, W., GULLAND, F., HILDEBRAND, J., HOUSER, D., HULLAR, T., JEPSON, P. D., KETTEN, D., MACLEOD, C. D., MILLER, P., MOORE, S., MOUNDAIN, D. C., PALKA, D., PONGANIS, P., ROMMEL, S., ROWLES, T., TAYLOR, B., TYACK, P., WARTZOK, R. GISINER, MEAD, J., & BENNER, L. 2006. Understanding the impacts of anthropogenic sound on beaked whales. Journal of Cetacean Research and Management. 7(3):177-187
DERUTIER, S. L., SOUTHALL, B. L., CALAMBOKIDIS, J., ZIMMER, W. M. X., SADYKOVA, D., FALCONE, E. A., FRIEDLAENDER, A. S., JOSEPH, J. E., MORETTI, D., SCHORR, G. S., THOMAS, L. & TYACK, P. L. 2013. First direct measurements of behavioural responses by Cuvier’s beaked whales to mid-frequency active sonar. Biology Letters. 9:1-5
FALCONE, E. A., SCHORR, G. S., DOUGLAS, A. B., CALAMBOKIDIS, J., HENDERSON, E., MCKENNA, M. F., HILDEBRAND, J. & MORETI, D. 2009. Sighting characteristics and photo-identification of Cuvier’s beaked whales (Ziphius cavirostris) near San Clemente Island, California: a key area for beaked whales and the military? Marine Biology. 156:2631-2640
FERNÁNDEZ, A. 2004. Pathological findings in stranded beaked whales during the naval military manoeuvres near the Canary Islands. In: EVANS, P. G. H. & MILLER, L. A. (eds). 2004. Proceedings of the Workshop on Active Sonar and Cetaceans. Las Palmas, Gran Canaria, 8th March 2003, European Cetacean Society Newsletter, Nº 42. Special Issue
FERNÁNDEZ, A., EDWARDS, J. F., RODRÍGUEZ, F., ESPINOSA DE LOS MONTEROS, A., HERRÁEZ, P., CASTRO, P., JABER, J. R., MARTÍN, V. & ARBELO, M. 2005. “Gas and Fat Embolic Syndrome” involving a mass stranding of beaked whales (Family Ziphiidae) exposed to anthropogenic sonar signals. Veterinary Patology. 42:446-457
FISCUS, C. H. 1997. Cephalod beaks in a cuvier’s beaked whale (Ziphius cavirostris) from Amchitka Island, Alaska. Marine Mammal Science. 13(3):481-486
FRANTZIS, A. 1998. Does acoustic testing strand whales? Nature. 392:29-30
FRANTZIS, A., ALEXIADOU, P., PAXIMADIS, G., POLITI., E., GANNIER, A. & CORSINI-FOKA, M. 2003. Current knowledge of the cetacean fauna of the Greek Seas. Journal of Cetacean Research and Management. 5(3):219-232
FRANTZIS, A. 2004a. The first mass stranding that was associated with the use of active sonar (Kyparissiakos Gulf, Greece, 1996). In: EVANS, P. G. H. & MILLER, L. A. (eds). 2004. Proceedings of the Workshop on Active Sonar and Cetaceans. Las Palmas, Gran Canaria, 8th March 2003, European Cetacean Society Newsletter, Nº 42. Special Issue
FREITAS, L. 2004. The stranding of three Cuvier’s beaked whales Ziphius cavirostris in Madeira Archipelago – May 2000. In: EVANS, P. G. H. & MILLER, L. A. (eds). 2004. Proceedings of the Workshop on Active Sonar and Cetaceans. Las Palmas, Gran Canaria, 8th March 2003, European Cetacean Society Newsletter, Nº 42. Special Issue
GANNIER, A. & ESPINAT, J. 2008. Cuvier’s beaked whale distribution in the Mediterranean Sea: results from small boat surveys 1996 – 2007. Journal of the Marine Biological Association of the United Kingdom. 88(6):1245-1251
GANNIER, A. 2011. Using existing data on focused surveys to highlight Cuvier’s beaked whales favourable areas: A case study in the central Tyrrenian Sea. Marine Pollution Bulletin. 63:10-17
HOLCER,D., NOTARBARTOLO DI SCIARA, G., FORTUNA, C. M., LAZAR, B. & ONOFRI, V. 2007. Occurence of Cuvier’s beaked whales in the southern Adriatic Sea: evidence of an important Mediterranean habitat. Journal of the Marine Biological Association of the United Kingdom. 87:359-362
IUCN 2012. Marine Mammals and Sea Turtles of the Mediterranean and Black Seas. Gland, Switzerland and Malaga, Spain: IUCN. 32 pages.
JEFFERSON, T. A., WEBBER, M. A. & PITMAN, R. L. 2008. Marine mammals of the world: A comprehensive guide to their identification. Academic Press. Canadà
MACLEOD, C. D., SANTOS M. B. & PIERCE G. J. 2003. Review of data on diets of beaked whales: evidence of niche separation and geographic segregation. Journal of the Marine Biological Association of the United Kingdom. 83:651-665
MACLEOD, C. D. & D’AMICO, A. 2006. A review of beaked whale behaviour and ecology in relation to assessing and mitigating impacts of anthropogenic noise. Journal of Cetacean Research and Management. 7(3):211-221
MARTÍN, V., SERVIDIO, A. & GARCÍA, S. 2004. Mass stranding of beaked whales in the Canary Islands. In: EVANS, P. G. H. & MILLER, L. A. (eds). 2004. Proceedings of the Workshop on Active Sonar and Cetaceans. Las Palmas, Gran Canaria, 8th March 2003, European Cetacean Society Newsletter, Nº 42. Special Issue
MCSWEENEY, D. J., BAIRD, R. W. & MAHAFFY, S. D. 2007. Site fidelity, associations and movements of Cuvier’s (Ziphius cavirostris) and Blainville’s (Mesoplodon densirostris) beaked whales off the island of Hawai’i. Marine Mammal Science. 23(3):666-687
NOTARBARTOLO DI SCIARA, G. 2002. Cetacean species occurring in the Mediterranean and Black Seas. In: G. NOTARBARTOLO DI SCIARA (Ed.), Cetaceans of the Mediterranean and Black Seas: state of knowledge and conservation strategies. A report to the ACCOBAMS Secretariat, Monaco, February 2002. Section 3, 17 p.
NOTARBARTOLO DI SCIARA, G. & BIRKUN A JR. 2010. Conserving whales and dolphins in the Mediterranean and Black seas. An ACCOBAMS status report. ACCOBAMS, Monaco. 212 p
PERRIN, W. F., WÜRSIG, B. & THEWISSEN, J. G. M. 2009. Encyclopedia of marine mammals. Second edition. Academic Press. United States of America
PODESTÀ, M., D’AMICO, A., PAVAN, G., DROUGAS, A., KOMMENOU, A. & PORTUNATO, N. 2006. A review of Cuvier’s beaked whale strandings in the Mediterranean Sea. Journal of Cetacean Research and Management. 7(3):251-261
REEVES, R. & NOTARBARTOLO DI SCIARA, G. 2006. The status and distribution of cetaceans in the Black Sea and Mediterranean Sea. IUCN Centre for Mediterranean Cooperation, Malaga, Spain. 137 pp.
SANTOS, M. B., PIERCE, G. J., HERMAN, J., LÓPEZ, A., GUERRA, A., MENTE, E. & CLARKE, M. R. 2001. Feeding ecology of Cuvier’s beaked whale (Ziphius cavirostris): a review with the information on the diet of this species. Journal of the Marine Biological Association of the United Kingdom. 81:687-694
SHIRIHAI, H & JARRET, B. 2006. Whales dolphins and seals: A field guide to the marine mammals of the world. A & C Black, London
SMITH, J. 2010. The ecology of Cuvier’s beaked whale, Ziphius cavirostris (Cetacea: Ziphiidae), in the Bay of Biscay. University of Southampton, UK, Graduate School of the National Oceanography Centre, PhD Thesis, 214 pp.
TAYLOR, B.L., BAIRD, R., BARLOW, J., DAWSON, S.M., FORD, J., MEAD, J.G., NOTARBARTOLO DI SCIARA, G., WADE, P. & PITMAN, R.L. 2008. Ziphius cavirostris. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2.
TYACK, P. L., JOHNSON, M., AGUILAR SOTO, N., STURLESE, A. & MADSEN, P. T. 2006. Extrem diving of beaked whales. The Journal of Experimental Biology. 209:4238-4253