Striped Dolphin
Encyclopedia
The Striped Dolphin is an extensively studied dolphin
that is found in temperate
and tropical waters of all the world's oceans.
; however, recent genetic work by LeDuc et al. (1999) indicates that Stenella
, as traditionally conceived, is not a natural group. According to that study, the closest relatives of the Striped Dolphin are the Clymene Dolphin
, the Common Dolphin
s, the Atlantic Spotted Dolphin
, and "Tursiops" aduncus
, which was formerly considered a subspecies of the Bottlenose Dolphin
. The Striped Dolphin was described by Franz Meyen
in 1833. The specific name coeruleoalba (from Latin caeruleus 'dark blue' and albus 'white') refers to the characteristic blue and white stripes on the flanks.
, Atlantic Spotted Dolphin
, Clymene Dolphin
). However its colouring is very different and makes them relatively easy to notice at sea. The underside is blue, white or pink. There are one or two black bands that circle the eyes, and then run across the back, to the flipper. These bands widen to the width of the flipper which are the same size. There are two further black stripes running from behind the ear - one is short and ends just above the flipper. The other is longer and thickens along the flanks until it curves down under the belly just prior to the tail stock. Above these stripes the dolphin's flanks are coloured light blue or grey. All appendages are black as well. At birth, individuals weigh about 10 kg
(22 pounds
) and are up to a meter (3 feet) long. By adulthood they have grown to 2.4 m (8 ft) (females) or 2.6 m (8.5 ft) (males) and weigh 150 kg (330 lb) (female) or 160 kg (352 lb) (male). Research suggest that sexual maturity was reached at 12 years in Mediterranean females and in the Pacific at between 7 and 9 years. Longevity is about 55–60 years. Gestation
lasts approximately 12 months and there is a three or four year gap between calving.
In common with other dolphins in its genus, the Striped dolphin moves in large groups - usually in excess of up to thousands of individuals in size. Groups may be smaller in the Mediterranean and Atlantic. They may also mix with Common Dolphin
s. The Striped dolphin is as capable as any dolphin at performing acrobatics - frequently breaching and jumping far above the surface of the water. Sometimes, it approaches boats in the Atlantic and Mediterranean but this is dramatically less common in other areas, particularly in the Pacific where it has been heavily exploited in the past.
The Striped Dolphin feeds on small pelagic fish
and squid
.
, the Indian Ocean
and the Pacific Ocean. Roughly speaking it occupies a range running from 40° N to 30° S. It has been found in water temperatures ranging from 10 to 26 degrees Celsius, though the standard range is 18-22 degrees. In the western Pacific, where the species has been extensively studied, a distinctive migration pattern has been identified. This has not been the case in other areas. The dolphin appears to be common in all areas of its range, though that may not be continuous in areas of low population density do exist. The total population is in excess of two million.
Attempts have been made to keep the Striped Dolphin in captivity. However these have all failed, with animals dying within two weeks due to failure to feed.
), since they have an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.
In addition, the Striped dolphin is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS
), the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS
), the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU) and the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (Western African Aquatic Mammals MoU)
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
that is found in temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
and tropical waters of all the world's oceans.
Taxonomy
The Striped Dolphin is one of five species traditionally included in the genus StenellaStenella
Stenella is a genus of aquatic mammals in Delphinidae, the family informally known as the oceanic dolphins.Currently five species are recognised in this genus:*Pantropical Spotted Dolphin, S. attenuata*Atlantic Spotted Dolphin, S. frontalis...
; however, recent genetic work by LeDuc et al. (1999) indicates that Stenella
Stenella
Stenella is a genus of aquatic mammals in Delphinidae, the family informally known as the oceanic dolphins.Currently five species are recognised in this genus:*Pantropical Spotted Dolphin, S. attenuata*Atlantic Spotted Dolphin, S. frontalis...
, as traditionally conceived, is not a natural group. According to that study, the closest relatives of the Striped Dolphin are the Clymene Dolphin
Clymene Dolphin
The Clymene dolphin , in older texts known as the Short-snouted spinner dolphin, is a dolphin endemic to the Atlantic Ocean.- Taxonomy :...
, the Common Dolphin
Common dolphin
The common dolphin is the name given to two species of dolphin making up the genus Delphinus.Prior to the mid-1990s, most taxonomists only recognised one species in this genus, the common dolphin Delphinus delphis...
s, the Atlantic Spotted Dolphin
Atlantic Spotted Dolphin
The Atlantic Spotted Dolphin is a dolphin found in the Gulf Stream of the North Atlantic Ocean. Older members of the species have a very distinctive spotted coloration all over their body.-Taxonomy:...
, and "Tursiops" aduncus
Indo-Pacific Bottlenose Dolphin
The Indo-Pacific bottlenose dolphin is a species of bottlenose dolphin. The Indo-Pacific bottlenose dolphin grows to long, and weigh up to . It lives in the waters around India, northern Australia, South China, the Red Sea, and the eastern coast of Africa. Its back is dark grey and its belly...
, which was formerly considered a subspecies of the Bottlenose Dolphin
Bottlenose Dolphin
Bottlenose dolphins, the genus Tursiops, are the most common and well-known members of the family Delphinidae, the family of oceanic dolphins. Recent molecular studies show the genus contains two species, the common bottlenose dolphin and the Indo-Pacific bottlenose dolphin , instead of one...
. The Striped Dolphin was described by Franz Meyen
Franz Meyen
Franz Julius Ferdinand Meyen was a German physician and botanist.Meyen was born in Tilsit. In 1830 he wrote Phytotomie, the first review of plant anatomy...
in 1833. The specific name coeruleoalba (from Latin caeruleus 'dark blue' and albus 'white') refers to the characteristic blue and white stripes on the flanks.
Physical description
The Striped Dolphin has a similar size and shape to several other dolphins that inhabit the waters that it does (see Pantropical Spotted DolphinPantropical Spotted Dolphin
The Pantropical Spotted Dolphin is a species of dolphin found in all the world's temperate and tropical oceans. The species was beginning to come under threat due to the killing of millions of individuals in tuna purse seines...
, Atlantic Spotted Dolphin
Atlantic Spotted Dolphin
The Atlantic Spotted Dolphin is a dolphin found in the Gulf Stream of the North Atlantic Ocean. Older members of the species have a very distinctive spotted coloration all over their body.-Taxonomy:...
, Clymene Dolphin
Clymene Dolphin
The Clymene dolphin , in older texts known as the Short-snouted spinner dolphin, is a dolphin endemic to the Atlantic Ocean.- Taxonomy :...
). However its colouring is very different and makes them relatively easy to notice at sea. The underside is blue, white or pink. There are one or two black bands that circle the eyes, and then run across the back, to the flipper. These bands widen to the width of the flipper which are the same size. There are two further black stripes running from behind the ear - one is short and ends just above the flipper. The other is longer and thickens along the flanks until it curves down under the belly just prior to the tail stock. Above these stripes the dolphin's flanks are coloured light blue or grey. All appendages are black as well. At birth, individuals weigh about 10 kg
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
(22 pounds
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...
) and are up to a meter (3 feet) long. By adulthood they have grown to 2.4 m (8 ft) (females) or 2.6 m (8.5 ft) (males) and weigh 150 kg (330 lb) (female) or 160 kg (352 lb) (male). Research suggest that sexual maturity was reached at 12 years in Mediterranean females and in the Pacific at between 7 and 9 years. Longevity is about 55–60 years. Gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....
lasts approximately 12 months and there is a three or four year gap between calving.
In common with other dolphins in its genus, the Striped dolphin moves in large groups - usually in excess of up to thousands of individuals in size. Groups may be smaller in the Mediterranean and Atlantic. They may also mix with Common Dolphin
Common dolphin
The common dolphin is the name given to two species of dolphin making up the genus Delphinus.Prior to the mid-1990s, most taxonomists only recognised one species in this genus, the common dolphin Delphinus delphis...
s. The Striped dolphin is as capable as any dolphin at performing acrobatics - frequently breaching and jumping far above the surface of the water. Sometimes, it approaches boats in the Atlantic and Mediterranean but this is dramatically less common in other areas, particularly in the Pacific where it has been heavily exploited in the past.
The Striped Dolphin feeds on small pelagic fish
Pelagic fish
Pelagic fish live near the surface or in the water column of coastal, ocean and lake waters, but not on the bottom of the sea or the lake. They can be contrasted with demersal fish, which do live on or near the bottom, and reef fish which are associated with coral reefs.The marine pelagic...
and squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
.
Population and distribution
The Striped Dolphin likes temperate or tropical, off-shore waters. It is found in abundance in the North and South Atlantic Oceans, including the Mediterranean and Gulf of MexicoGulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
, the Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
and the Pacific Ocean. Roughly speaking it occupies a range running from 40° N to 30° S. It has been found in water temperatures ranging from 10 to 26 degrees Celsius, though the standard range is 18-22 degrees. In the western Pacific, where the species has been extensively studied, a distinctive migration pattern has been identified. This has not been the case in other areas. The dolphin appears to be common in all areas of its range, though that may not be continuous in areas of low population density do exist. The total population is in excess of two million.
Human interaction
Japan has hunted Striped Dolphins in the western Pacific since at least the 1940s. In the heyday of "striped dolphin drives", at least 8,000 to 9,000 individuals were killed each year and in one exceptional year 21,000 individuals were killed. Since the 1980s, following the introduction of quotas, this number has fallen to around 1,000 kills per year. Conservationists are concerned about the Mediterranean population which is threatened by pollution, disease, busy shipping lanes and heavy incidental catches in fishing nets.Attempts have been made to keep the Striped Dolphin in captivity. However these have all failed, with animals dying within two weeks due to failure to feed.
Diet
The adult Striped Dolphin eats fish, squid, octopus, krill, and other crustaceans. Mediterranean striped dolphins seem to prey primarily on cephalopods (50-100% of stomach contents), while northeastern Atlantic striped dolphins most often prey on fish, frequently cod. They mainly feed on cephalopods, crustaceans, and bony fishes. They feed anywhere within the water column where prey is concentrated and they can dive to depths of 700 metres to hunt deeper-dwelling species.Conservation
The Eastern tropical Pacific and Mediterranean populations of the Striped dolphin are listed on Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMSBonn Convention
The Convention on the Conservation of Migratory Species of Wild Animals aims to conserve terrestrial, marine and avian migratory species throughout their range...
), since they have an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.
In addition, the Striped dolphin is covered by the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS
ASCOBANS
ASCOBANS is a regional agreement on the protection of small cetaceans that was concluded as the “Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas” under the auspices of the UNEP Convention on Migratory Species, or Bonn Convention, in September 1991 and came into force...
), the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (ACCOBAMS
ACCOBAMS
ACCOBAMS, the Agreement on the Conservation of Cetaceans in the Black Sea,Mediterranean Sea and contiguous Atlantic area is ‘a cooperative tool for the conservation of marine biodiversity in the Mediterranean and Black Seas’....
), the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU) and the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (Western African Aquatic Mammals MoU)
External links
- ARKive - images and movies of the striped dolphin (Stenella coeruleoalba)
- Whale and Dolphin Conservation Society
- Whale Trackers - An online documentary series about whales, dolphins and porpoises.
- Convention on Migratory Species page on the Striped dolphin
- Official website of the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area
- Official website of the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas
- Official website of the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region
- Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia