Home to cetaceans

The southern seas: a jewel named Teno-Rasca

A world of biodiversity!

The cetacean family is made up of whales, dolphins and porpoises. They are marine mammals that breathe using their lungs, maintain their bodies at a constant temperature and give birth to and suckle their young.

The island of Tenerife is the jewel in the crown of the Atlantic Ocean. Over a third of its total area is protected. Located on the southwestern coast of Tenerife, the municipality of Arona is home to one of the island’s most ecologically important coastal areas: the Teno-Rasca marine reserve. Its importance is recognised at an European level, as the European Commission has declared it a special area of conservation and it forms part of the Natura 2000 network. (SAC) No 103- TF ES 7020017.

The Canary Islands are known throughout the world as one of the best places to observe cetaceans. Of the 81 known cetacean species, 27 can be observed in the Canaries throughout the year, making the islands a source of immense ecological wealth. Moreover, two of these species, the bottlenose dolphin and short-finned pilot whale, have made their permanent waters around Arona home, meaning we can observe these family groups all year round.

Snout

Spiracle

Melon

Its geographical location, oceanographic characteristics and wide variety of seabed environments ensure that the Teno-Rasca reserve plays a key role in the lifes and development of both its resident and visiting cetacean species.

Eye

Dorsal fin

Bryde`s whale Short-fined pilot whale

Navel

Foto: Guillermo Vazquez

Mammary slit Caudal Peduncle

Tail fin

Adapted to life at sea

Cetaceans are divided into the Odontoceti, or toothed whales (dolphins, sperm whales and beaked whales), and Mysticeti, or baleen whales (rorquals and balaenids). These names come from Greek, and have the following meanings:

Cetaceans are descendants from land mammals that evolved around 50 million years ago into the animals we know today. These modern cetaceans have developed a more hydrodynamic appearance and are extraordinarily well-adapted to the marine environment. In order to adapt completely, primitive whales had to undergo major morphological changes over time and adapt their sensory structures and abilities to suit life under water.

Adaptations

Million year (M.Y.)

Gráphic evolution

Pakicetus

The teeth of the Odontoceti are all identical, and the animals enjoy a varied diet. They eat fish of all sizes, along with cephalopods and shellfish, and use echolocation to find their prey. They only have one nasal orifice, or blowhole, and it is smaller than that of baleen whales.

Odontocetos

49 M. Y.

Protocetus

45 M. Y.

These whales have two blowholes, which are usually larger in size than those of their toothed cousins.

Code of ethics: whale-watching companies Although the skin of adult cetaceans is not covered with hair or fur, it contains a thick layer of blubber that provides perfect thermal insulation to protect the animals from the cold.

The skeleton was adapted to make it lighter and enable the animal to move faster and increase flexibility.

Cetaceans’ eyes are small in proportion to their size and they have no tear glands; however, they secrete an oily substance that protects the eye against the salinity and friction of the water.

The forelimbs evolved into pectoral fins, which the animal uses as rudders to control its quick movements. The rear limbs disappeared.

The spinal column lengthened and a tailfin evolved, which the animal uses to propel itself through the water.

The genital organs and mammary glands are protected behind folds of muscle or genital slits.

Echolocation: Toothed whales have a powerful sonar that allows them to interpret their surroundings using sound. We call this “echolocation”.

Mysticeti Aetiocetus

Cetotherium

24 M. Y.

15 M. Y.

Observing cetaceans in their natural habitat is an infinitely rewarding experience. However, to make sure these animals continue to have a home in the Canary Islands, and to allow us to continue watching them, legislation has been introduced at a national and international level to regulate this activity through a code of ethical conduct and ensure the animals are observed in a respectful manner.

Boats that have been authorised for professional whale-watching are identified by a special “blue boat” flag. These boats are committed to following the ethical code of conduct and have a specialist guide on board to provide detailed information about the animals and their environments.

— Swimming with the animals, feeding them, touching them or disturbing them with noises.

— Throwing rubbish or any other waste materials into the sea.

— Flying over the area in order to watch the animals.

— Using sonar equipment.

— Sailing in circles or reversing in the observation area.

The following whale-watching rules must be respected: — Maintain a minimum distance of 60 metres from the animal.

— Maximum observation time: 30 minutes.

— Travel at reduced speed.

— Avoid a high number of boats around the same group of animals.

List of authorised boats in Arona.

Current cetaceans

Odontoceti

These whales emit a series of vibrations or clicks from beneath their blowhole, which they then concentrate into a sheet of sound waves using the mass of fatty tissue (a sort of sound lens) located in the melon. After these sound waves hit and bounce back off rocks, fish or other dolphins, the animal receives the echo through its lower jaw, where it travels along fluid-filled sinuses to the inner ear. From there, it is transferred to the brain, which then interprets the information contained in the echo.

The following are strictly forbidden:

This system of location is used by other animals, such as bats, to orientate themselves at night.

The echolocation technology is used by humans in submarines.

Mysticeti

Foto: Bart Bogaert

The nasal orifice gradually moved to the top of the head, becoming what we call a “blowhole”. Other external organs (like the ears) disappeared, although the inner ear remains visible as a tiny orifice behind the eye.

Risso`s dolphin

50 M. Y.

Ambulocetus

The Mysticeti have baleen plates which allow them to feed on small crustaceans such as krill, while the whales in the rorqual family are also able to consume shoals of fish. The tongue of the baleen whales plays an important role in feeding, as the pressure it exerts allows the whales to filter the food and expel the leftover water from their mouths.

Fotos: Chloe Yzoard

Anus

Toothed or baleen?

Mysti + ceti = hair cetaceans.

Odonto + ceti = toothed cetaceans.

Atlantic spotted dolphin

Pectoral fins

Foto: Jesús Estrada

ARONA

Home to cetaceans

Whales and dolphins: marine mammals

BAHRIYELI – Puerto de los Cristianos Tlfno. 922 751 576 www.mardeons-tenerife.com JOLLY ROGER - Puerto de los Cristianos Tlfno. 922 751 576 www.mardeons-tenerife.com TRAVELIN`LADY - Puerto de Los Cristianos Tlfno. 609 488 039

MUST CAT Puerto deportivo La Marina del Sur. Las Galletas Tlfno. 922 786 814 www.mustcat.es PETER PAN – Puerto de los Cristianos.

Tlfno. 922 789 044/ 666 542 880 www.barcostenerife.com

How to identify a cetacean

1

There are various aspects to take into account when identifying a species, such as the way the animal behaves when breaching or submerging, the way it exhales, the size of the group, and morphological characteristics, for example:

Bryde’s whale / Balaenoptera edeni

Maximum length: 15 metres Frequency of observation: Seasonal – early autumn and spring Identification guide: This whale has three crests on its head, positioned lengthwise. It is dark grey in colour, becoming lighter towards the stomach area. It also has ventral ridges up to the navel area.

­ The size of the animal — ­— The shape and position of the dorsal fin (if it has one) ­— The shape of the head ­— The colour of the body 2

Sperm whale / Physeter macrocephalus

3

Maximum length: 18 metres Frequency of observation: Resident Identification guide: Large, square-shaped head. The blowhole is at the front of the head towards the left. These whales spout forwards and off-centre. They have wrinkled, dark-coloured skin, with a very small dorsal fin. They show their tailfin before submerging and can remain underwater for nearly two hours.

4

5

Killer whale / Orcinus orca

Maximum length: 18 metres Frequency of observation: Occasional Identification guide: Large, square-shaped head. The blowhole is at the front of the head towards the left. These whales spout forwards and off-centre. They have wrinkled, dark-coloured skin, with a very small dorsal fin. They show their tailfin before submerging and can remain underwater for nearly two hours.

Blainville’s beaked whale / Mesoplodon densirostris

Maximum length: 5 metres Frequency of observation: Resident Identification guide: Robust body. Long snout with a curved mouth and flattened melon. Mature males have two teeth in their lower jaw. Brown or grey in colour, with a large number of cracks. Small, triangular dorsal fin located towards the rear of the animal’s back.

Delfín mular / Tursiops truncatus Maximum length: 2.7 metres Frequency of observation: Resident Identification guide: Short snout, separated from the melon.

6

Short-finned pilot whale / Globicephala macrorhynchus

Maximum length: 5.5 metres Frequency of observation: Resident Identification guide: Dorsal fin curved backwards; round head.

The base of the dorsal fin is wider in males. Dark grey/near black in colour, with a lighter patch on the back.

7

Risso’s dolphin / Grampus griseus

Maximum length: 3.5 metres Frequency of observation: Sporadic Identification guide: Robust body. Short snout, barely separated from the prominent melon. Light grey in colour, with abundant white patches that increase in proportion to age.

8 Short-beaked common dolphin / Delphinus delphis Maximum length: 2.5 metres Frequency of observation: Seasonal Identification guide: Prominent snout, clearly separated from the melon. Yellow colouration throughout its body, against a black background.

9 10 Atlantic spotted dolphin / Stenella frontalis 11 Rough-toothed dolphin / Steno bredanensis

Maximum length: 2.6 metres Frequency of observation: Sporadic, though it can be seen all year round. Identification guide: Cone-shaped head without an indent between the melon and snout.

Long, almost triangular dorsal fin. This dolphin gets its name from its large teeth, which have lengthwise ridges.

Maximum length: 2 metres Frequency of observation: Seasonal Identification guide: Prominent snout, clearly separated from the melon.

Adults have white spots or freckles.

Striped dolphin / Stenella coeruleoalba

Maximum length: 2.2 metres Frequency of observation: Sporadic Identification guide: Shorter snout, clearly separated from the melon. Blue in colour, with a number of stripes or streaks between its snout and pectoral fins.

Note: The illustrations are not to scale and the animals are not shown in their true proportion to one another. The average size for each species is given in metres. © Chloe Yzoard Ilustrations Collaborate: Asociación Tonina Printed: Imprenta Reyes, S.L.