Throughout the season we will present one cetacean per article, to learn more about these animals and how to observe them. These sheets are proposed by Serge Briez founder of the ‘’Les Peuples de la Mer’’ (translated in english : Peoples of the Sea), a citizen NGO which goal is the protection through knowledge of a Mediterranean maritime area: the Gulf of Lion.
Today, we present the Striped Dolphin, a common sight in the Mediteranean Sea beloved by boaters who cross their path!
Sheet 2 : The Striped Dolphin
(Stenalla coeruleoalba)
Observation area in the Mediterranean Sea
The striped dolphin is often seen in the Mediterranean where it is very present. They are estimated to number between 120,000 in the western Mediterranean, which makes them the most represented species. They can be found in coastal areas but rather on the high seas where they live in groups that sometimes represent several hundred individuals.
More commonly, the groups encountered in the southern Gulf of Lions are made up of around forty, their structures are complex and variable. Sometimes they include only males, or only females or mixed with breeders or not.
In the south of the Gulf of Lion where they are very present. We can observe them in groups of 40 to more than 100. They are very dynamic, with robust bodies showing different color pattern. Their jaws have many sharp teeth, nearly a hundred pairs spread over both jaws.
3 facts about the Striped dolphin
1 – Alike the Bottlenose Dolphin , the striped dolphin is a top predator as well. It regulates lower trophic levels and helps to report on the health of an entire ecosystem. Its importance is major and even if this species is not endangered, the IUCN International Union for the Conservation of Nature has classified the striped dolphin as “least concern” but “vulnerable in the Mediterranean”.
They are targeted for hunting in Japan, and driftnets do a lot of damage in the Atlantic. They are prone to epidemics: The morbillivirus causes significant neurological and pulmonary damage, it can cause the death of hundreds of individuals, as has already happened in the past in the Mediterranean: 1000 striped dolphins were found dead in 1990, 200 in 2007 and 50 in 2011. (source GIS3M)
2 – Gestation time is around 12-13 months, the dolphin is weaned after 18 months, there is a significant peak in mortality at the time of weaning. Their social life is complex and poorly understood. Once weaned, the young can stay 1 to 2 years in the mixed group with their mother. Then later join a group of young individuals and then adults. Sexual maturity is between 5-13 years for females and 7-15 years for males.
3 –The striped dolphin can be recognized by their slender silhouette and the characteristic design that adorns its sides: a thin black line stretches from the eye towards the bottom. The white covers its sides and rises in a “brush stroke” or in a clear “flame” towards the ridge. Males and females have a lifespan of up to 58 years. Fast swimmers, they regularly swim in the bow of boats and slam the surface with their heads, jump very high and even perform stunts: a high, long jump in which they twirl their tail.
Observation and interaction tips
1 – Swimming with striped dolphins is not recommended. In the Gulf of Lion, for example, it is even forbidden to approach within 100 m. of course if they choose to come swimming close to the bow which is frequent, or visit you during a swim in the sea, you can enjoy it while not exceeding 5 knots and maintaining a straight and parallel trajectory without trying to to rejoin. When meeting while swimming, never try to touch them, their skin is extremely fragile.
2 – Do not try to feed them, they are great hunters and a good part of their time is devoted to hunting. They can descend to depths of 200-700 m and hunt in the evening and at night taking advantage of the nocturnal ascents of their prey. Small fish and cephalopods are their favorite menus.
3 – The best way to observe striped dolphins is not to look for them but to keep an eye out. The encounter can be opportunistic: your paths cross, but these encounters can also be the subject of a different way of NAVIGATING TO OBSERVE and meeting all the species that inhabit our Big Blue.
Observing is learning and many associations offer eco-volunteers naturalistic observation embarkations where you will learn a lot about these MASTERS of the oceans, the Cetaceans.
In the meantime, we’ll meet you very soon for the next sheet produced in collaboration with The Peoples of the Sea, which will present the Rossi’s dolphin by its scientific name Grampus griseus! Find all the cetacean sheets of the Peoples of the Sea here!
See you soon for new discoveries on the marine fauna of the Mediterranean.
Fair Winds Captain,
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