Arxiu d'etiquetes: sperm whale

Cetaceans of the Mediterranean Sea

Did you know that in the Mediterranean Sea habitually lives 8 species of cetaceans, among dolphins and whales; in addition to other visitor and spontaneous species, such as the killer whale? In this post, a new version of “Cetaceans in the Catalan coast“, the first post published in this blog, I will give more information about the cetaceans that live in this small sea. 

INTRODUCTION

Cetaceans originated 50 million years ago in the ancient Tethys Sea, from terrestrial mammals. Approximately, there are 80 living species in the world, but only 8 of them live habitually in the Mediterranean and other species are present only in some seasons or sporadically.

HABITUAL CETACEANS OF THE MEDITERRANEAN SEA

STRIPED DOLPHIN 

Striped dolphin (Stenella coeruleoalba) is a cetacean with a black or bluish grey colouration in the back and white in the ventral part. There is a black line from the eye to the anal region through each side, and another one from the eye to the pectoral fin. Mediterranean striped dolphins are slightly smaller than their neighbours from the Atlantic, and achieve a maximum length of 2.2 m.

Stenella coeruleoalba delfin listado cetáceos mediterraneo
Striped dolphin (Stenella coeruleoalba) (Picture: Scott Hill National Marine Mammal Laboratory, Creative Commons).

They may live in big groups, till hundreds of individuals. Anyway, in the observations that I have done in the Mediterranean, groups included from 5 to 50 animals. They are very acrobatics and they can jump 7 meters above the sea surface.

Striped dolphins are common in both Mediterranean basins, specially in the open sea, being so many abundant in Ligurian Sea, Gulf of Lion, Alboran Sea (between Andalucía, Spain, and Morocco) and the Balearic Sea (between the Iberian Peninsula and the Balearic Islands).

This is the most abundant species in the Mediterranean (about 117,000 animals in the western basin), but they are in a vulnerable status of conservation due to the affection by morbillivirus, pollutants such as organochlorine compounds and fishing devices.

BOTTLENOSE DOLPHIN 

Bottlenose dolphins (Tursiops truncatus) maybe are the most known for the population because they are the protagonist of some movies and they are the most common cetacean in captivity.

delfin mular tursiops truncatus cetaceos mediterraneo
Bottlenose dolphin (Tursiops truncatus) (Picture: Gregory Slobirdr Smith, Creative Commons).

Their robust body is grey, clearer in the sides and white in the abdomen. Bottlenose dolphins are 4 m long.

Their groups, integrated by females and offspring or young males, range from 2 to 10 animals. They live in all the coasts of the Mediterranean Sea.

Their conservation status in the Mediterranean is vulnerable. It is though that their population is about 10,000 animals. Competence with commercial fisheries, bycatch and water pollution are among their threats.

SHORT-BEAKED COMMON DOLPHIN 

Short-beaked common dolphin (Delphinus delphis) is easily recognisable for the colouration of its body: dorsal region is dark and sides are cream-coloured or yellow, and constitute a V in the half of the body. Like striped dolphins, they are also small animals (2-2.5 m).

delfin comun delphinus delphis cetaceos mediterraneo
Short-beaked common dolphin (Delphinus delphis) (Picture: JKMelville, Creative Commons).

They live in numerous groups in open waters, from 10 to 200 animals, but sometimes groups of several thousands have been seen.

They enjoy with boats:

Despite their name, it is difficult to observe them because they are endangered in the Mediterranean. In the last 40 years, their population have been reduced by half. There are several reasons: lack of preys due to competence with fishers, bycatch, habitat degradation, sound pollution and high concentrations of pollutants.

FIN WHALE

Fin whale (Balaenoptera physalus) is the biggest whale in the Mediterranean and the second one in the world.

rorcual comun balaenoptera physalus cetaceos mediterraneo circe
Fin whale (Balaenoptera physalus) (Picture: Circe)

Fin whale’s head is V-shaped, wide and flatten. It is dark grey in the back and white in the abdomen, but asymmetric in the jaws: left side is dark grey and right side is white. Dorsal fin is short and placed in the last third of the body. In the moment of diving, caudal fin is not shown out of the water. Blow may be 8 meters height and narrow. Their maximum length is 24 m.

They are usually seen alone or in small groups (normally mother and calf) in open waters. In the Mediterranean, they are most frequently sighted between Balearic Islands and Ionian Sea, being specially abundant in the Gulf of Lion.

According to IUCN, it is a vulnerable species in the Mediterranean, but it is endangered worldwide. The Mediterranean population includes 5,000 adults. They are victims of strikes with ships, high DDT concentrations, acoustic pollution due to seismic surveys and bycatch.

Have you seen this fin whale rescue from Fuerteventura?

SPERM WHALE

Sperm whales (Physeter macrocephalus)  are the biggest toothed whales and one of the biggest cetaceans in the Mediterranean.

cachalote-physeter-macrocephalus-cetaceos-mediterraneo
Sperm whale (Physeter macrocephalus) (Picture: Gabriel Barathieu, Creative Commons).

Sperm whales have a rounded or triangular hump instead of a dorsal fin, which is followed by six exaggerated “knuckles”. An important clue for its identification is the blow: it is a bushy blow directed low, left and forwards. Head, which is square, represent 1/3 of the total length of the body. It is dark or grey, with the lower part of the mouth white. To dive, they show the caudal fin out of the water. They may be 20 long.

Their groups are composed by females and their offspring, other groups of young males and adult males are solitary. The number of animals per group ranges from 10 to 15, but smaller groups also exist. They are usually seen in oceanic waters of all the Mediterranean.

It is an endangered species in the Mediterranean due to they are accidentally captured in fishing nets, by strikes with vessels and the annoyance provoked by marine traffic. It is estimated that live some thousands in the Mediterranean.

Have you seen this video of a sperm whales that “adopt” a deformed cetacean?

RISSO’S DOLPHIN 

Risso’s dolphin (Grampus griseus) is grey when is born, but becomes paler with age for the presence of scars that do not disappear. They might measure 4 m.

calderon gris grampus griseus cetaceos mediterráneo
Risso’s dolphin (Grampus griseus) (Picture: Rob, Creative Commons).

Generally, they live in groups of 3-50, despite sometimes groups of some thousands have been spotted. In the Mediterranean, it is widely distributed in open waters, being more abundant in the western basin, where they prefer continental slope and submarine canyons.

Their status of conservation is unknown, but bycatch and acoustic and chemical pollution affect them.

LONG-FINNED PILOT WHALE

Long-finned pilot whale (Globicephala melas) is the biggest dolphin species in the Mediterranean, since it may achieve 6 m. Black in general, this pilot whale has a anchor-shaped ventral patch. Its flippers measure one fifth of the length.

globicephala melas calderón común cetáceos mediterráneo
Long-finned pilot whale (Globicephala melas) (Picture: Wikiwand).

Their groups range from 10 to 60 animals, but also several thousands. Groups include several generations of females with their calves. In the Mediterranean, it is abundant in the western basin, specially in the Strait of Gibraltar and Alboran Sea.

There is deficient data to evaluate its status of conservation. Anyway, it is known that are threatened by bycatch, strikes and acoustic and chemical pollution.

CUVIER’S BEAKED WHALE

Cuvier’s beaked whales (Ziphius cavirostris) are dark grey or brown, paler in the head. Their head is bulky, and the beak is not much marked. They may be 7 m long.

zifio cuvier ziphius cavirostris cetaceos mediterraneo
Cuvier’s beaked whale (Ziphius cavirostirs) (Picture: WDC).

They usually live in groups of 2-7 individuals or alone, in deep oceanic waters.

It is difficult to observe them due to the little activity in surface, reason that can explain why there are not enough information to evaluate their conservation status. It is known that are specially sensible to acoustic pollution, both military activities or seismic surveys. Moreover, the ingestion of plastic and bycatch also affect them.

KILLER WHALES IN THE MEDITERRANEAN?

Killer whales (Orcinus orca) are one of the most fascinating cetaceans. They live in polar and tropical waters, from the coast to open sea.

orca orcinus orca cetáceos mediterraneo
Killer whale (Orcinus orca) (Picture: Jose J. Díaz)

In the Mediterranean, however, they are only considered residents in the Strait of Gibraltar, with a size population of 32 whales. Their presence in the Strait, it is believed that is linked to the presence of bluefin tuna, their food.

Did you know that they use different dialects to communicate each other? Did you know that homosexual behaviours have been described in this species? Albino killer whales have been reported.

Their status of conservation is unknown, but direct death by fishers, reduction of their preys, annoyances and habitat degradation are among the causes of their reduction.

REFERENCES

  • CRAM: Cetacis
  • Day, T (2008). Guía para observar ballenas, delfines y marsopas en su hábitat. Ed. Blume
  • Gobierno de Canarias: Curso de Observación de Cetáceos
  • IUCN (2012). Marine Mammals and Sea Turtles of the Mediterranean and Black Seas. Gland, Switzerland and Malaga, Spain: IUCN
  • Kinze, CC (2002). Mamíferos marinos del Atlántico y del Mediterráneo. Ed. Omega
  • Lleonart, J (2012). Els mamífers marins i els seus noms. Terminàlia, 5, 7-25
  • Notarbartolo di Sciara G. (compilers and editors) (2006). The status and distribution of cetaceans in the Black Sea and Mediterranean Sea. IUCN Centre for Mediterranean Cooperation, Malaga, Spain.
  • Cover picture: Scuba Diver Life

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Anuncis

Cetaceans with dialects: the killer whale and the sperm whale

Last week, the press was full of news about a recent article that highlight that sperm whales in the Eastern Pacific have distinct dialects. For this reason, the post of this week will explain what a dialect is (in cetaceans), which cetaceans have dialects in addition to sperm whales and which is the explanation to this. 

INTRODUCTION

The first question to be answered is “What is a dialect?”. This question is not simple because sometimes this concept is confused with another one: geographic variation. While dialects are song differences between neighbouring populations of potentially interbreeding individuals, geographic variations refer to differences in song over long distances and between populations which normally do not come together. In the case of dialects, the explanation of their presence is social learning, while in geographic variations the reason can be found in their genes. The function of dialects is to be an acoustical signature that help maintain cohesion and integrity of groups and as an inbreeding avoidance mechanism.

CETACEANS WITH DIALECTS

To date, dialects have been described in two cetacean species: killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus). These two species have several features in common:

  • They live in matrilineal groups, that are highly stable groups of individuals linked by maternal descent that protect themselves against predators and other dangers.
  • They live in multilevel societies, that consist of hierarchically nested social levels. From the upper to the lowest level, there are three levels: vocal clans, social units and individuals. This kind of societies are also present in human and other primates and in African elephants.

KILLER WHALE DIALECTS

Dialects have been found in resident killer whales from the northeastern Pacific, Norway and Kamchatka. In this species, these dialects consists on repertories of several call types that are different among pods. Each pod have distinctive features in the call repertories and, therefore, each pod has a particular dialect. Pods that share part of the repertories constitute acoustic clans. So, each clan is acoustically different. Pods from different clans can overlap and interact and new pods can be formed by fission of other pods, which turn out in divergence of dialects.

Killer whales are one of the cetacean species with dialects (Picture: Oceanwide Science Institute).
Killer whales (Orcinus orca) are one of the cetacean species with dialects (Picture: Oceanwide Science Institute).

SPERM WHALE DIALECTS 

Sperm whales have repertories that varied in the proportional usage of different coda types and classes. Sperm whale codas are stereotyped sequences of 3-40 broad-band clicks usually lasting less than 3 seconds in total, which functions are to help maintain group cohesion, reinforce bonds, aid negotiations and collective decision-making. These groups with distinct dialects also interact. To give a particular example, in the South Pacific and the Caribbean, there are six sympatric acoustic clans based on coda sharing, which simultaneously differ in movement and habitat use patterns and in feeding success.

Dialects have been described in sperm whales (Physeter macrocephalus) (Picture: CBC News).
Dialects have been described in sperm whales (Physeter macrocephalus) (Picture: CBC News).

ORIGIN OF DIALECTS IN CETACEANS

A recently published article in the magazine Nature suggests a mechanism that may explain the origin of multilevel societies in sperm whales. As we have seen, it is in these societies where dialects are present in cetaceans. So, here we will explain the origin of multilevel societies in sperm whales as an example.

In sperm whales, the upper level of the multilevel society are clans of individuals that communicate between them using similar codas. These clans are originated from cultural transmission via biased social learning of codas, when they learn the most common codas (conformism) from behaviourally similar individuals (homophily). Thus, the result are groups with increasingly homogeneous behaviour with a strong integration. The cultural transmission plays a key role in the partitioning of sperm whales into sympatric clans (clans that live together but without interbreeding). So, it is in these clans where distinctive behavioural patters may appear, like dialects. The lower level, social units, are originated from ecological, cognitive and time constraints and benefits.

Multilevel societies (Picture: Marc Arenas Camps).
Multilevel societies. Individuals (stars and filled circles) are the lowest level and in association (black lines) with other individuals they constitute social units (empty black circles). Socials units with acoustic similarity (orange lines) form vocal clans (blue and green). It is in vocal clans where dialects can emerge (Picture: Marc Arenas Camps).

HUMPBACK WHALES: A DIFFERENT CASE

The differences in the songs of humpback whales (Megaptera novaengliae) cannot be considered dialects since they happen between geographically isolated populations. Due to a geographic and reproductive isolation, these differences have appeared as a result of genetic distinctions among populations.

REFERENCES

  • Cantor, M; Shoemaker, LG; Cabral, RB; Flores, CO, Varga, M & Whitehead, H (2015). Multilevel animal societies can emerge from cultural transmission. Nature Communications. 6:8091. DOI: 10.1038/ncomms9091
  • Conner, DA (1982). Dialects versus geographic variation in mammalian vocalizations. Animal Behaviour. 30, 297-298
  • Dudzinski, KM; Thomas, JA & Gregg, JD (2009). Communication in Marine Mammals. In Perrin W, Würsig B & Thewissen JGM (edit.). Encyclopedia of Marine Mammals. Academic Press (2 ed).
  • Ford, JKB (2009). Dialects. In Perrin W, Würsig B & Thewissen JGM (edit.). Encyclopedia of Marine Mammals. Academic Press (2 ed).

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Cetaceans have a negative response to summer maritime traffic in Westeran Mediterranean Sea

A team of researchers of several Italian organizations has published on May 2015 its findings about the responses of cetaceans in high sea waters to summer maritime traffic in the Western Mediterranean Sea. This post is a summary of this study. 

INTRODUCTION

Nowadays, cetaceans have to face several threats, like the loss of their habitat, depletion of resources, interaction with fisheries and chemical and acoustic pollution, among others. In the case of ship transport, it can cause long-term changes in distribution, short-term changes in behaviour or direct physical injuries (e. g. collisions).

The Mediterranean Sea is one of the world’s busiest waterways. Moreover, shipping traffic is growing together with the concern of its impacts on fauna. In addition, we have to have in consideration that summer month are the busiest in naval traffic, especially due to the increase on cruise ships and passenger ferries.

The goal of this study was to outcome if the intensity of traffic in high sea waters was statistically different between presence and absence of cetacean sightings.

STUDY AREA AND DATA COLLECTION

Because of most of the Mediterranean cetaceans are mainly pelagic and there is a lack of information in these areas, the research had been conducted along six transects within shipping routes that connects Italy, France and Spain in high sea waters (placed in Ligurian-Provençal basin, the northern and central Tyrrhenian Sea and the Sardinian and Balearic Seas).

Mediterranean Sea basin (Picture from Encylopaedia Britannica)
Mediterranean Sea basin (Picture from Encylopaedia Britannica)

The transects were surveyed from June to September between 2009 and 2013 using ferries as observation platforms. During this period, more than 95,000 km were surveyed and the presence of eight cetacean species was recorded.

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CETACEANS AND MARITIME TRAFFIC

In locations with cetacean sightings, the number of vessels was 20% lower than the number of vessels in the absence of sightings. In the case of the three most frequently sighted species; fin whale (Balaenoptera physalus), striped dolphin (Stenella coeruleoalba) and sperm whale (Physeter macrocephalus); this difference was, respectively, 18%, 20% and 2%. Concerning other species, in the case of Cuvier’s beaked whale (Ziphius cavirostris) the difference was 29% and in the Risso’s dolphin (Grampus griseus) was 43%. It was found that for bottlenose dolphins (Tursiops truncatus) the difference was insignificant. Finally, for common dolphin (Delphinus delphis) and for pilot whale (Globicephala melas) any conclusion can be given.

Nevertheless, despite the number of ships recorded during cetacean sightings was lower in all areas, the percentage difference range from 11 to 49% among areas.

So, in high sea areas during summer, where cetaceans were seen, there were a significantly lower abundance of ships. Some explanations can be given: animals could tend to avoid more impacted zones with small displacements by seeking areas with fewer vessels, could change their distribution to occupy low traffic areas or could increase diving activity where intense traffic occurs. The intensity of the response of cetaceans to the intensity of traffic has important differences among areas and species. So, there are several factors that affects this percentage difference, like specific ecological needs and local environmental conditions. 

In the case of fin whale, where marine traffic is intense, the presence of fin whales is generally lower, with the exception occurring in the central part of the Ligurian Sea. The explanation could be that this region is ecologically favourable in summer since it is a feeding ground for this species and these whales are present for feeding reasons. Therefore, there is a coexistence between traffic and fin whales.

Fin whale (Balaenoptera physalus) (Picture from Circe)
Fin whale (Balaenoptera physalus) (Picture from Circe)

Another example is striped dolphin. Due to its high mobility, this dolphin can avoid the presence of vessels and this could be the reason why there is a negative response between this species and ship presence.

Striped dolphin (Stenella coeruleoalba) (Picture from Marc Arenas Camps)
Striped dolphin (Stenella coeruleoalba) (Picture from Marc Arenas Camps)

About sperm whale and Cuvier’s beaked whale, there were no difference in both species in the Ligurian Sea and the reason probably is that sperm and Cuvier’s beaked whale have their feeding grounds in this basin and, moreover, the slopes and submarine canyons are confined in specific areas. However, differences are observed in other areas.

Sperm whale (Physeter macrocephalus) (Picture from Gabriel Barathieu).
Sperm whale (Physeter macrocephalus) (Picture: Gabriel Barathieu, Creative Commons).
Cuvier's beaked whale (Ziphius cavirostris) (Picture: Todd Pusser, Arkive).
Cuvier’s beaked whale (Ziphius cavirostris) (Picture: Todd Pusser, Arkive).

Finally, bottlenose dolphin did not show any response to traffic. Probably, because it is a coastal species, it is more used to sharing its typical habitat with maritime traffic.

Bottlenose dolphin (Tursiops truncatus) (Picture: Brandon Cole).
Bottlenose dolphin (Tursiops truncatus) (Picture: Brandon Cole).

REFERENCES

This post has been based on this paper:

  • Campana, I; Crosti, R; Angeletti, D; Carosso, L, David, L; Di-Méglio, N; Moulins, A; Rosso, M; Tepsich, P & Arcangeli, A (2015). Cetacean response to summer maritime traffic in the Western Mediterranean Sea. Marine Environmental Research, 109, 1-8

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Albinism in cetaceans

This publication talk about albinism in cetaceans and give some examples about it.

WHAT IS ALBINISM?

Albinism is a group of inherited conditions resulting in little or no pigment (hypopigmentation) in the eyes or in the eyes, skin and hair. Mammals’ pigmentation depends on the presence or absence of melanin in the skin, hair and eyes. Melanin is produced by amino acid tyrosine thanks to enzyme tyrosinase, whose alteration cause albinism. The other case is the overproduction, known as melanism, and the result is overly dark animals.

ALBINO CETACEANS

Albino marine mammals have been reported for 21 cetacean species (Fertl et al. 1999; Ferlt et al. 2004) and 7 pinniped species (Rodriguez & Bastida, 1993; Bried & Haubreux, 2000). Some cetacean species are sperm whales (Physeter macrocephalus), bottlenose dolphins (Tursiops truncatus) and killer whales (Orcinus orca).

Chédiak-Higashi Syndorme is a type of albinism that consists on diluted pigmentantion patterns that appear pale gray eye, white blood cell abnormalities and a shortened life span. It was detected on Chimo, a female killer whale (picture).

chimo
Chimo, an albino killer whale (Picture: Orcinus orca).

Albinism means some associated problems to marine mammals: it reduces the heat absorption in colder waters, it eases the detection for depredators, it increases the eye and skin sensibility to sunlight and it reduces the visual communication.

REFERENCES

  • FERTL, D; PUSSER, L. T.; & LONG, J. J. (1999) First record of an albino bottlenose dolphin (Tursiops truncatus) in the Gulf of Mexico, with a review of anomalously white cetaceans. Mar. Mamm. Sci. 15, 227-23
  • PERRIN, W. F.; WÜRSIG, B; THEWISSEN, J. G. M. Encyclopedia of Marine Mammals (Ed. Academic Press, 2ª edició)

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Cetaceans in the catalan coast

The goal of this publication is to describe the different cetaceans that live in the catalan coast. At first, I will explain you what is a cetacean and then I will describe them.

INTRODUCTION

Cetaceans are a mammal order that live adapted to swimming and, for this reason, they develop all the activities in the water. Most of them live in the sea, but there are a small group that live in fresh water. This adaptation consists on the presence of hydrodynamic bodies to reduce the resistance and the presence of fins (pectorals, dorsal and caudal fins). Cetaceans, as well as the rest of the mammals, are homeotherms (they have physiological mechanisms to keep a constant temperature of the body, known as warm-blooded). Furthermore, they breath air and, for this reason, their nostrils are dorsal, called blowhole. More or less, there are 80 species of cetaceans, subdivided on: odontoceti (toothed cetaceans, which includes dolphins, porpoises, beluga, narwhal, beaked whales and sperm whales) and mysticti (cetaceans without teeth; which includes whales and fin whales).

8 species live in the coast of Catalonia: common bottlenose dolphin, short-beaked common dolphin, striped dolphin, fin whale, sperm whale, Risso’s dolphin, long-finned pilot whale and Cuvier’s beaked whale.

COMMON BOTTLENOSE DOLPHIN

Common bottlenose dolphin (Tursiops truncatus) is the most typical dolphin in zoos. We can recognise them for the color of their skin: mainly is grey, but the abdomen is lighter. The dorsal fin is convex. This dolphins usually live in groups of 2 – 15 individuals, but sometimes the groups are composed for several hundreds. They are very acrobatic. Common bottlenose dolphin has the global conservation status of “least concern”, but in the Mediterranean Sea is “vulnerable” (UICN).

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Common bottlenose dolphin (Tursiops truncatus) (Foto: Sheilapic76, Creative Commons).

SHORT-BEAKED COMMON DOLPHIN

Short-beaked common dolphin (Delphinus delphis) is easily recognisable for the color patron. Its back is grey or brown with a V drawing under the dorsal fin. In addition, they have a yellowish patch and a grey patch in the sides that form a typical hourglasse figure. They usually live in groups of 10 – 200 individuals. Like, common bottlenose dolphins, they are good acrobats. They are endangered in the Mediterranean Sea, but in global their category from UICN is “least concern”.

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Short-beacked common dolphin (Delphinus delphis) (Foto: Jolene Bertoldi, Creative Commons).

STRIPED DOLPHIN

Striped dolphins (Stenella coeruleoalba) have a brown or grey dorsal fin, moderately high; dark and prominent beak, well distinguished from the melon (a lump of fatty tissue that forms the forehead of toothed whales and tht is thought to function as a means of focusing sound for echolocation); and its back is grey or brown, light grey from the center of each side to dorsal fin and in the subsequent part. Moreover, they have a thin dark line from the beak to the lower part of sides. They normally live in groups of 25 – 100 individuals. They are good acrobats too. Striped dolphin is the most abundant cetacean in the North West of the Mediterranean Sea, but its status is vulnerable here.

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Striped dolphin (Stenella coeruleoalba) (Foto: 20minutos).

FIN WHALE

Fin whale (Balaenoptera physalus) is the biggest cetacean of the catalan coast. Fin whales have a high dorsal fin, placed at last third of the body and a wide and flattened head. Their body is long and dark grey without spots, more lighter in the abdomen. You can’t usually see their caudal fin. Their conservation status is “vulnerable” in de Mediterranean Sea, but is “endangered” in global.

rorqual comú
Fin whale (Balaenoptera physalus) (Foto: UW Today).

SPERM WHALE

Sperm whale (Physeter macrocephalus) is another big cetacean in Mediterranean Sea. The lobes of the tail are wide and triangular, with an important groove; they have an small hump, followed for six protuberances; their head is rounded and represent one third of the body; and their body color is dark grey to brown violet. Their blast is leaning and place a little in the left. They usually swim slowly. Spearm whale is catalogued as “vulnerable” in global for UICN, but in the Mediterranean is “endangered”.

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Sperm whale (Physeter macrocephalus) (Foto: Advocacy Britannica).

RISSO’S DOLPHIN

Risso’s dolphin (Grampus griseus), known like grey dolphin too, has a high dorsal fin, long sharp pectoral fins, a rounded head with a bulbous melon, a curved mouth and a grey to brown color, with several marks and lighter abdomen. They usually live in groups of 3 – 30 individuals, but sometimes they live in groups of several miles. Their conservation status is “least concern” in general, but there isn’t enough information for Mediterranean.

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Risso’s dolphin (Grampus griseus) (Foto: El hogar natural).

LONG-FINNED PILOT WHALE

Long-finned pilot whale (Globicephala melas) has a short, wide rounded dorsal fin; high and narrow pectoral fins that mesure a fifth part of the body; a bulbous melon; a short snout; and the color of its body is dark grey, black or brown. They normally live in groups of 10 – 60 individuals. There isn’t enough information to evaluate their conservation status.

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Long-finned piolt whale (Globicephala melas) (Foto: El hogar natural).

CUVIER’S BEAKED WHALE

Cuvier’s beaked whale (Ziphius cavirostris) is a species with a little surface activity and for this reason is very hard to see it. Its caudal fin has wide lobes, without a central groove or very small and lightly sickle-shaped. The dorsal fin is placed behind the center of the body. The snout is short, curved and cream-coloured. The color of the body is brown reddish to dark grey, with darker abdomen. They usually live in groups of 2 – 7 members, ocasionally untill 25, but older males normally live alone. There isn’t enough information to evaluate their conservation status.

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Cuvier’s beaked whale (Ziphius cavirostirs) (Foto: Aceytuno).

This are the 8 most tipical species in the coast of Catalonia. I hope that with this small guide you could identify them easily.

REFERENCES

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