Arxiu d'etiquetes: cetacean

Symbiosis: relationships between living beings

Predation, parasitism, competition… all living beings, besides interacting with the environment, we relate to other living beings. What types of relationships in addition to those you know? Do you feel like to know them?

INTRODUCTION

The group of all living beings in an ecosystem is called biocenosis or community. The biocenosis is formed in turn by different populations, which would be the set of individuals of the same species occupying an area. For survival, it is imperative that relations between them are established, sometimes beneficial and sometimes harmful.

INTERESPECIFIC RELATIONSHIPS

They are those that occur between individuals of different species. This interaction it is called symbiosis. Symbiotic relationships can be beneficial to a species, both, or harmful to one of the two.

Detrimental to all the species involved:

Competition: occurs when one or more resources are limiting (food, land, light, soil …). This relationship is very important in evolution, as it allows natural selection acts by promoting the survival and reproduction of the most successful species according to their physiology, behavior …

Las selvas son un claro ejemplo de competencia de los vegetales en busca de la luz. Selva de Kuranda, Australia. Foto de Mireia Querol
Rainforests are a clear example of competition between vegetals in the search for light. Kuranda rainforest, Australia. Photo by Mireia Querol
One species has benefits and the other is detrimented:
  • Predation: occurs when one species (predator) feeds on another (prey). This is the case of cats, wolves, sharks
foca, león marino,
Great white shark (Carcharodon carcharias) jumping to depretade a marine mamal, maybe a sea lion. Photo taken from HQ images.
  • Parasitism: one species (parasite) lives at the expense of other (host) and causes it injury. Fleas, ticks, pathogenic bacteria are the best known, but there are also vertebrate parasites, like the cuckoo that lay their eggs in the nests of other birds, which will raise their chicks (brood parasitism). Especially interesting are the “zombie parasites”, which modify the behavior of the host. Read this post to learn more!
    Carricero (Acrocephalus scirpaceus) alimentando una cría de cuco (Cuculus canorus). Foto de Harald Olsen
    Reed warbler (Acrocephalus scirpaceus) feeding a cuckoo’s chick (Cuculus canorus). Photo by Harald Olsen

    Parasites that live inside the host’s body are called endoparasites (such as tapeworms), and those who live outside ectoparasites (lice). Parasitism is considered a special type of predation, where predator is smaller than prey, although in most cases does not cause the death of the host. When a parasite causes illness or death of the host, it is called pathogen.

    Cymothoa exigua es un parásito que acaba sustituyendo la lengua de los peces por su propio cuerpo. Foto de Marcello Di Francesco.
    Cymothoa exigua is a parasite that replaces the tongue of fish with their own body. Picture by Marcello Di Francesco.

Kleptoparasitism is stealing food that other species has caught, harvested or prepared. This is the case of some raptors, whose name literally means “thief.” See in this video a case of kleptoparasitism on an owl:


Kleptoparasitism can also occur between individuals of the same species.

One species has benefits and the other is not affected:
  • Commensalism: one species (commensal) uses the remains of food from another species, which does not benefit or harm. This is the case of bearded vultures. It is also commensalism the use as transportation from one species over another (phoresy), as barnacles attached to the body of whales. The inquilinism is a type of commensalism in which a species lives in or on another. This would apply to the woodpeckers and squirrels that nest in trees or barnacles living above mussels. Finally, metabiosis is the use of the remains of a species for protection (like hermit crabs) or to use them as tools.
    El pinzón carpintero (Camarhynchus pallidus) utiliza espinas de cactus o pequeñas ramas para extraer invertebrados de los árboles. Foto de
    The woodpecker finch (Camarhynchus pallidus) uses cactus spines or small branches to remove invertebrates from the trees. Picture by Dusan Brinkhuizen.
    Both species have benefits:
  • Mutualism: the two species cooperate or are benefited. This is the case of pollinating insects, which get nectar from the flower and the plant is pollinated. Clownfish and anemones would be another typical example, where clown fish gets protection and food scraps while keeps predators away and clean parasites of the sea anemonae. Mutualism can be optional (a species do not need each other to survive) or forced (the species can not live separately). This is the case of mycorrhizae, an association of fungi and roots of certain plants, lichens (mutualism of fungus and algae), leafcutter ants

    Las hormigas Atta y Acromyrmex (hormigas cortadoras de hogas) establecen mutualismo con un hongo (Leucocoprinus gongylophorus), en las que recolectan hojas para proporcionarle nutrientes, y ellas se alimentan de él. Se trata de un mutualismo obligado. Foto tomada de Ants kalytta.
    Atta and Acromyrmex ants (leafcutter ants) establish mutualism with a fungus (Leucocoprinus gongylophorus), in which they gather leaves to provide nutrients to the fungus, and they feed on it. It is an obligate mutualism. Photo taken from Ants kalytta.

INTRAESPECIFIC RELATIONSHIPS

They are those that occur between individuals of the same species. They are most beneficial or collaborative:

  • Familiars: grouped individuals have some sort of relationship. Some examples of species we have discussed in the blog are elephants, some primates, many birds, cetaceans In such relationships there are different types of families.
  • Gregariousness: groups are usually of many unrelated individuals over a permanent period or seasonal time. The most typical examples would be the flocks of migratory birds, migration of the monarch butterfly, herds of large herbivores like wildebeest, shoal of fish

    El gregarismo de estas cebras, junto con su pelaje, les permite confundir a los depredadores. Foto tomada de Telegraph
    Gregariousness of these zebras, along with their fur, allow them to confuse predators. Photo taken from Telegraph
  • Colonies: groups of individuals that have been reproduced asexually and share common structures. The best known case is coral, which is sometimes referred to as the world’s largest living being (Australian Great Barrier Reef), but is actually a colony of polyps (and its calcareous skeletons), not single individual.
  • Society: they are individuals who live together in an organized and hierarchical manner, where there is a division of tasks and they are usually physically different from each other according to their function in society. Typical examples are social insects such as ants, bees, termites

Intraspecific relations of competition are:

  • Territorialityconfrontation or competition for access to the territory, light, females, food can cause direct clashes, as in the case of deer, and/or develop other strategies, such as marking odor (cats, bears), vocalization

    Tigres peleando por el territorio. Captura de vídeo de John Varty
    Tiger figthing for territory. Video caption by John Varty
  • Cannibalism: predation of one individual over another of the same species.

And you, as a human, have you ever thought how do you relate with individuals of your species and other species?

MIREIA QUEROL ALL YOU NEED IS BIOLOGY

REFERENCES

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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.

Introductory online course on cetaceans. Now, 40% off, till 30th June. Available only in Spanish. More info here. Click the picture to access to the coupon. 

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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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Satellite tagging

In this post we are going to talk about satellite tagging, a methodology for the studying of cetacean animals.

 

Satellite tagging is an information obtaining process thanks to systems present in animals: in this case, present in cetaceans previously captured and installed the transmitter at dorsal fin (in porpoises, bottlenose dolphins and killer whales) or at blubber (in humpback whale, southern right whale and blue whale). In short-term behaviour studies, it’s possible to join the transmitters to skin with suction pads. This systems can accumulate the information (data loggers) or they can send it by satellite. Often, these systems have video camaras to show what the animals are watching each moment.

The information got with this method allows to study the movements, behaviour, population structure and the recovery of populations.

 

DATA LOGGERS

This system records lots of data with different equipments that give information about behaviour (sounds, swimming speed…), fisiology (heartbeat rate, body temperature, stomach temperature…) and the environment (depth, water temperature, light intensity, sounds…). The recording interval can be regulated, depending the goal of study.

This system has some advantages: to keep information spend less energy than its transmisson, are smaller and less bulky and it can save lots of information. The problem is the difficulty of getting the equipment again.

 

INFORMATION TRANSMISSION SYSTEMS

The most important is telemetry via satellite, with a transmitter that sends the data via satellite to a receiver station with a computer. These systems get information about the animal position, immersion depth, swimming speed and water temperature to study the environment factors that affect to distribution, movements and feeding behaviour.

Them use is restricted: they can just send the information in the water surface, the environment sounds are overlaped with cetacean sounds and they need lots of energy. The advantage is the hability of giving information in real time to a working center.

 

The bibliography used to write this post is:

ANILAM, RESEARCH AND CONSERVATION, Métodos de investigación de cetáceos: http://www.alnilam.info/index.php/es/investigacion/inv-metodos

AUSTRALIAN GOVERNMENT, DEPARTMENT OF THE ENVIRONMENT, Non-lethal research techniques for studying whales: http://www.environment.gov.au/coasts/species/cetaceans/publications/fs-techniques.html

CIRCE, Metodologías aplicadas por CIRCE en sus programas de investigación: http://www.circe.biz/index.php?option=com_content&view=article&id=86&Itemid=180&lang=es

TRUJILLO, F & DIAZGRANADOS, M. C., Curso de técnicas de estudio de mamíferos acuáticos: manual básico, La Isla de los Delfines – Fundación Omacha, 2005

 

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Introduction to research methodology

This post is an introduction to cetacean research methodology, where there is a list of different methods and what you can study with them. En the following publications, you will find an specific information of each one.

 

The study of cetaceans at sea consists on the study of its ecology, like an individual (feeding, social and reproductive behaviour) and like a group (space and time’s distribution, abundance and population tendencies). There are different methods to study cetaceans in theses different aspects:

1) Observations: you can study the abundance and distribution.

2) Acoustic research methods: you can study the distribution, abundance and feeding and reproductive behaviour.

3) Individual identification (Photo-identification and mark-recapture): you are able to study the abundance, movements, reproduction and survival.

4) Satellite tagging: you can study the movements, feeding behaviour and survivial.

5) Genetic methods: you are able to study the reproduction, genetics and diet.

6) Geographic Information Systems: you can study the area use, density, feeding and reproduction zones, movements and conservation.

 

The bibliography that have been used to develope this topic is the following:

ANILAM, RESEARCH AND CONSERVATION, Research methods: http://www.alnilam.info/index.php/en/investigacion/inv-metodos

AUSTRALIAN GOVERNMENT, DEPARTMENT OF THE ENVIRONMENT, Non-lethal research techniques for studying whales: http://www.environment.gov.au/coasts/species/cetaceans/publications/fs-techniques.html

BERNASCONI, M et al. Use of active sonar for cetacean conservation and behaviorial-ecology studies: a paradox? Proceedings of the Institute of Acoustics, 2009, Vol. 31. Pt. 1

CAÑADAS, A et al. Recopilación, Análisis, Valoración y Elaboración de Protocolos sobre las Labores de Observación, Asistencia a Varamientos y Recuperación de Mamíferos y Tortugas Marinas de las Aguas Españolas. Sociedad Española de Cetáceos. 1999

CIRCE, Metodologías aplicadas por CIRCE en sus programas de investigación: http://www.circe.biz/index.php?option=com_content&view=article&id=86&Itemid=180&lang=es

MARTINS, C.C.A GIS as a tool to identify priority areas for humpback whale conservation at Eastern Brazilian Coast. 2009

PITTMAN, S & COSTA, B. Linking Cetaceans tot their Environment: Spatial Data Acquisition, Digital Processing and Predictive Modeling for Marine Spatial Planning in the Northwest Atlantic. Biogeography Branch, Center for Coastal Monitoring & Assessment, National Oceanic and Atmospheric Administration, 2009, Chapter 21

THOMAS, Peter O. Metodology for behavioural studies of cetaceans: right whale mother – infant behaviour. Rep. Int. Whal. Commn. 1986

TRUJILLO, F & DIAZGRANADOS, M. C., Curso de técnicas de estudio de mamíferos acuáticos: manual básico, La Isla de los Delfines – Fundación Omacha, 2005

 

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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.

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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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