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Lifespan, longevity, and ageing

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Maximum longevity: 46 years (wild) Observations: There are reports of pregnant females up to the age of 35. Their maximum longevity could be underestimated.
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Distribution

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Stenella attenuata lives in the Atlantic, Indian, and Pacific oceans. It migrates seasonally to the Japanese coast and is the most common cetacean in the Gulf of Mexico. (Lang 1996, Nowak 1997)

Biogeographic Regions: indian ocean (Native ); atlantic ocean (Native ); pacific ocean (Native )

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Morphology

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S. attenuata is referred to as the pantropical spotted dolphin because its skin becomes spotted as the dolphin grows older. Its dorsal surface is dark gray but covered in paler spots, while its paler ventral surface is covered with dark spots. Another distinguishing feature is the spotted dolphin's bright, white snout. It also has melon, a fatty area located on its forehead. The inshore spotted dolphins tend to be larger in size than offshore dolphins. Males also typically have larger body sizes than females, yet females have longer rostra. The spotted dolphin has between 29 and 37 small, rounded teeth on either side of its upper and lower jaws. It has pectoral fins (on the sides), a dorsal fin (on the central back), and tail flukes. The blowhole, used for breathing and communication, is located on the top of the head. Because S. attenuata has a thin layer of blubber, it has small amounts of stored energy, so it eats high energy foods to make up for the low energy. (Bernard et al. 1989, Lang 1996, Misek et al. 1997, Myers 1997, Nowak 1997, Perrin et al. 1994)

Range mass: 60 to 165 kg.

Other Physical Features: endothermic ; bilateral symmetry

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Life Expectancy

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Average lifespan
Status: wild:
46.0 years.

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Habitat

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S. attenuata lives in the tropical and subtropical areas of the ocean and seas. Although some live inshore, most members of the species live offshore, where the temperature of the deeper water remains fairly constant. The majority of this species live in between the equator and the Galapagos Islands for the same reason that they tend to live offshore. The home range is hundreds of kilometers in diameter. (Nowak 1997)

Aquatic Biomes: coastal

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Trophic Strategy

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The spotted dolphin finds its prey, squid and small fish, near the ocean surface. These dolphins have also been known to feed on isopods and pteropods. Lactating females eat significantly more fish than pregnant or normal spotted dolphins. The lactating female's deviation from the norm is presumably because she requires more energy than normal and pregnant dolphins. More protein and also more energy is obtained from eating fish, rather than from eating the same mass of squid. In addition, fish also contain more calcium and phosphorous, which aid in lactation. Lastly, fish have lower water content, which prevents additional water loss in the lactating female since the consumed fish are hypotonic with the sea water. (Bernard 1989, Lang 1996, Nowak 1997)

Animal Foods: fish; mollusks; aquatic crustaceans

Primary Diet: carnivore (Piscivore , Molluscivore )

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Benefits

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The spotted dolphin helps yellowfin tuna fishermen to locate their target. (Nowak 1997)

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Benefits

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Regulations designed to lessen the number of dolphins killed by tuna fishermen have increased the cost and complexity of the fishery.

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Conservation Status

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Because S. attenuata tend to swim with yellowfin tuna, Pacific fishermen use sightings of these dolphins to help them locate their yellowfin tuna targets. The majority of S. attenuata deaths are a consequence of yellowfin tuna fishing operations. The enormous nets used to catch these tuna can unintentionally entangle dolphins as well as fish. S. attenuata is the dolphin species that has been affected to the greatest extent by the tuna fish industry. Between 1985 and 1990, almost 130,000 were killed each year because of the tuna fish catching methods. Thanks to United States government regulations, such as requiring improvements in fishing equipment, this number has decreased substantially by 100,000 deaths per year. Some spotted dolphins are killed intentionally by Japanese fishermen. Between 500 and 2000 spotted dolphins are harvested annually in order to be eaten by the Japanese. (Bernard et al. 1989, Chives et al. 1993, Nowak 1997, Perrin et al. 1994)

IUCN Red List of Threatened Species: least concern

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Untitled

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The current population of spotted dolphins is estimated to be 2.2 million. The government should continue to maintain strict regulations to continue the decrease in mortality among S. attenuata. (Nowak 1997)

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Deanna Riseman, University of Michigan-Ann Arbor
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Behavior

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Perception Channels: tactile ; chemical

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Reproduction

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The mean age of sexual maturity for northern offshore female spotted dolphins is estimated to be 11.1 years, which is higher than the estimated age of 9.8 years for southern offshore females. On the other hand, males' average age of sexual maturity is 14.7 years. S. attenuata does not have any particular birthing season, although the number of births does rise in spring and autumn months. The time between births is between 26 and 36 months in the eastern Pacific and approximately 48 months near Japan. The gestation period lasts a little less than a year, and the lactation period can last for 1.5 years or longer. Females usually give birth to a single offspring (Bernard et al. 1989, Chivers et al. 1993, Nowak 1997)

Breeding interval: The time between births is between 26 and 36 months in the eastern Pacific and approximately 48 months near Japan

Breeding season: These dolphins breed year round

Average number of offspring: 1.

Range gestation period: 12 (high) months.

Average gestation period: 12 months.

Average weaning age: 18 months.

Average age at sexual or reproductive maturity (female): 9.8 to 11.1 years.

Average age at sexual or reproductive maturity (male): 14.7 years.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous

Average birth mass: 10000 g.

Average number of offspring: 1.

Average age at sexual or reproductive maturity (male)
Sex: male:
3956 days.

Average age at sexual or reproductive maturity (female)
Sex: female:
2983 days.

This lactation period is more than three times as long as other large whales. Occasionally females have been known to lactate during a new pregnancy, and some have also been known to give birth to twins, although this is rare. Mother dolphins feed near the surface so that they don't have to leave their calves. Pregnant females up to age 35 have been discovered.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); extended period of juvenile learning

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Riseman, D. 1999. "Stenella attenuata" (On-line), Animal Diversity Web. Accessed April 27, 2013 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Stenella_attenuata.html
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Biology

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The gregarious pantropical spotted dolphin forms schools that can range in size from less than one hundred to thousands of individuals (4); although it has been observed that these impressively large herds are less common in the eastern tropical Pacific than they once were, as exploitation takes its toll (4). The pantropical spotted dolphin is well known for its tendency to associate with schools of tuna in this region. While this may be due to an overlap in diet, other reasons for this association have also been suggested, such as increased protection from predators (2), as there is safety in numbers. This ocean mammal is a fast swimmer that often engages in a range of aerial acrobatics and will frequently ride the bow waves of boats, except for in tuna fishing grounds where it has learnt to avoid vessels (2) (4). Juveniles in particular are known to make astoundingly high vertical leaps out of the water (2). The pantropical spotted dolphin feeds mainly at night on small fish, squid and crustaceans that rise to near the surface at dusk, with flying fish forming a major part of the diet in some regions. In turn, this dolphin becomes prey for the killer whale (Orcinus orca) and a number of sharks (2). While the breeding system of this species is not known, it is possible that it may be promiscuous, like that of the closely related spinner dolphin (Stenella longirostris) (2). Every two to three years, mature female pantropical spinner dolphins give birth to a calf, after a gestation period of around 11 months (2). The calf is nursed for between one and two years. Females reach sexual maturity at 9 to 11 years, while males become sexually mature between the ages of 12 and 15 years (2).
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Conservation

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Once it had been noticed what enormous numbers of dolphins were being killed in tuna fisheries in the eastern Pacific, actions were implemented to try and reduce these unnecessary deaths. In the 1970s, the United States employed laws and measures aiming to reduce dolphin bycatch to levels approaching zero through improved fishing methods (6). In 1979, the Inter-American Tropical Tuna Commission began a dolphin conservation program, and soon, the idea of dolphin-safe tuna became popular, with the United States only allowing the sale of dolphin-safe tuna by 1994. In 1999, the International Dolphin Conservation Program Agreement came into force, which meant the major tuna fishing countries in the eastern Pacific were bound to certain measures such as having observers on boats and strict dolphin-mortality limits. As a result of all of these actions, dolphin mortality has fallen drastically (6), which will hopefully give the pantropical spotted dolphins, and other dolphin species, a much needed opportunity to recover.
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Description

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The most distinctive feature of the pantropical spotted dolphin is, as its name suggests, the spots that speckle the body of adults. Newborn calves are unspotted, but by adulthood, a varying amount of light spots cover the upper surface, and dark spots cover the dolphin's underside (2). Underneath this spotting, the slender, stream-lined body is grey, with a darker grey cape extending back from the head and sweeping low underneath the dorsal fin (2) (4). The dorsal fin is narrow and sickle-shaped (4). The long, thin beak of the pantropical spotted dolphin is separated from the melon by a distinct crease (2) (4). In most adults, the tip of the beak is white (2). Male pantropical spotted dolphins are slightly larger than females (2). A subspecies of the pantropical spotted dolphin is recognised, Stenella attenuate graffmani, which inhabits more coastal areas and can be distinguished in appearance by its larger, stockier body, thicker beak and more extensive spotting (4).
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Habitat

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As its name suggests, this dolphin inhabits tropical and warm-temperate seas, where it can be found in both near-shore and oceanic habitats (2).
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Range

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The pantropical spotted dolphin is a widely distributed species, occurring in all oceans between 40°N and 40°S (4) (5). Subspecies S. a. graffmani occurs in the eastern tropical Pacific from Mexico to northern Peru (2).
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Status

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Classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix II of CITES (3).
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Threats

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The tendency of the pantropical spotted dolphin to associate with tuna schools has been this species' downfall in the eastern tropical Pacific. Fishermen take advantage of this association to help them locate and catch tuna more efficiently (4), and will intentionally capture both tuna and dolphins together, then release the dolphins from the net (6). Either the dolphin is killed in the process, or this can lead to a single dolphin being chased, captured and released many times during its lifetime, causing a great deal of stress (6). In the eastern tropical Pacific, tuna fisheries have killed millions of dolphins since the 1960s (2) (5), reducing some stocks to a fraction of their former size (2). Today, mortality rates have been greatly reduced, yet the populations are not recovering from this devastating exploitation as well as could be expected; the stresses of being repeatedly chased and captured, as well as separation of mothers from their young, are possible reasons cited for the slow growth of the populations (5). Pantropical spotted dolphins are also hunted intentionally in some areas, such as in Japan, Solomon Islands and the Philippines, where they are caught for human consumption and fishing bait (2) (5). They are also taken as bycatch in many fisheries in developing countries around the globe, and in some countries, such as Peru, Ghana and the Philippines, the bycatch is kept and used for human consumption. This has lead to the evolution of directed catches as the markets for the meat develop, resulting in a growing conservation problem (2).
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Benefits

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The tuna fishery in the eastern tropical Pacific targets the pantropical spotted dolphin to catch yellowfin tuna and skipjack tuna that often swim below the herds. Annual mortality of spotted dolphins in the late 1980s was in the tens of thousands. Takes of hundreds of thousands per year in the 1960s and 1970s reduced the northern offshore stock of spotters to an unknown degree. Spotted dolphins are also taken in other fisheries, including drive fisheries in Japan and the Solomon Islands, and Sri Lankan gillnets and harpoon fisheries for human consumption, among others. Some have been reported taken in the Caribbean small cetacean fishery. IUCN: Insufficiently known.
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Marine mammals of the world. Jefferson, T.A., S. Leatherwood & M.A. Webber - 1993. FAO species identification guide. Rome, FAO. 320 p. 587 figs. . 
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Diagnostic Description

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Pantropical spotted dolphins (sometimes called "spotters") are generally slender, streamlined animals. They have a long thin beak that is separated from the melon by a distinct crease. The dorsal.fin is narrow, falcate, and usually pointed at the tip. Although unspotted at birth, by adulthood Pantropical spotted dolphins have varying degrees of white mottling on the dark dorsal cape, which is narrow on the head and sweeps low on the flank in front of the dorsal fin. The spotting ranges from very slight (or even non-existent) in offshore animals to heavy enough to obliterate the cape in coastal dolphins. The lower sides and belly of adults are grey and the lips and beak tip tend to be brilliant white. A dark grey band encircles the eye, and continues forward to the apex of the melon; there also is a dark gape-to-flipper stripe. In each tooth row are 34 to 48 slender, sharply pointed teeth. In at least the eastern tropical Pacific, a separate coastal form exists. It is larger and stockier, with a thicker beak and more extensive spotting than the offshore form.Can be confused with: Pantropical spotted dolphins can be confused with several other long-beaked oceanic dolphins. Spinner dolphins can be distinguished by differences in dorsal-fin shape, beak length, and colour pattern. In addition to Atlantic spotted dolphins both bottlenose and hump-backed dolphins can also be spotted (generally on the belly), but will often be distinguishable by differences in body shape and size.
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Marine mammals of the world. Jefferson, T.A., S. Leatherwood & M.A. Webber - 1993. FAO species identification guide. Rome, FAO. 320 p. 587 figs. . 
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Size

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Adults are from 1.6 to 2.4 m (females) or 1.6 to 2.6 m (males). Animals from offshore populations can weigh up to at least 120 kg, but are smaller than those from coastal ones. At birth, pantropical spotted dolphins are about 85 cm long.
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Marine mammals of the world. Jefferson, T.A., S. Leatherwood & M.A. Webber - 1993. FAO species identification guide. Rome, FAO. 320 p. 587 figs. . 
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Brief Summary

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These animals are among the most abundant dolphins in the eastern tropical Pacific and are the primary species involved in interactions with tuna there. Pantropical spotted dolphins associate with yellowfin tuna, spinner dolphins, and other pelagic predators; the fishermen take advantage of this association to help them locate and catch tuna more efficiently. School sizes are generally less than 100 for the coastal form, but offshore herds may number in the thousands. In the eastern tropical Pacific, large herds are less common than they were before the tuna fishery began to exploit them. These gregarious animals are fast swimmers, often engaging in acrobatics, and frequently bowriding (except on the tuna fishing grounds of the eastern tropical Pacific, where they generally have learned to avoid boats). There are 2 calving peaks in the eastern tropical Pacific, 1 in spring and 1 in autumn. Pantropical spotted dolphins feed largely on epipelagic fish and squid, primarily during the day.
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Marine mammals of the world. Jefferson, T.A., S. Leatherwood & M.A. Webber - 1993. FAO species identification guide. Rome, FAO. 320 p. 587 figs. . 
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Pantropical spotted dolphin

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The pantropical spotted dolphin (Stenella attenuata) 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. In the 1980s, the rise of "dolphin-friendly" tuna capture methods saved millions of the species in the eastern Pacific Ocean and it is now one of the most abundant dolphin species in the world.

Taxonomy

The species was first described by John Gray in 1846. Gray's initial analysis included the Atlantic spotted dolphin in this species. They are now regarded as separate. Both the genus and specific names come from Latin words meaning thin or thinning.

Two subspecies of the pantropical spotted dolphin are recognized:[4]

S. a. attenuata or offshore pantropical spotted dolphin, found worldwide in tropical waters
S. a. graffmani or coastal pantropical spotted dolphin, found in coastal waters in the eastern tropical Pacific

Another unnamed subspecies, which inhabits inland Hawaiian waters, was recognized in Rice (1998)'s overview of marine mammal taxonomy.[5]

Description

Pantropical spotted dolphins porpoising

The pantropical spotted dolphin varies significantly in size and coloration throughout its range. The most significant division is between coastal and pelagic varieties. The coastal form is larger and more spotted. (These two forms have been divided into subspecies only in eastern Pacific populations).

Spots are key defining characteristics in adults, though immature individuals are generally uniformly colored and susceptible to confusion with the bottlenose dolphin. Populations around the Gulf of Mexico may be relatively spot-free even in adulthood. In the Atlantic, confusion is possible with the Atlantic spotted dolphin.

The pantropical spotted dolphin is a fairly slender, streamlined animal, with a dark cape and light spots on its body that increase in number and size as it gets older. [6]This species has a long, thin beak and a falcate dorsal fin, which is the thinnest among dolphins.[6] The upper and lower jaws are darkly colored, but are separated by thin, white "lips". The chin, throat, and belly are white to pale grey with a limited number of spots. The flanks are separated into three distinct bands of color — the lightest at the bottom, followed by a thin, grey strip in the middle of the flank, and a dark-grey back. The tall concave dorsal fin is similarly colored. The thick tail stock matches the color of the middle band.

The vocal repertoire of the pantropical spotted dolphin has not been clearly documented. There is no published information about the acoustic signals from South Atlantic Ocean populations of the mammal. [7]

The pantropical spotted dolphin is very active and is prone to making large, splashy leaps from the sea. It is a common breacher and will often clear the water for a second or more. Bow-riding and other play with boats is common.

In the eastern Pacific, the dolphin is often found swimming with yellowfin tuna (hence the problem with dolphin deaths caused by tuna fishing). However, they do not feed on that fish. In fact, the two species have similar diets of small epipelagic fish. In other areas, the species may also feed on squid and crustaceans.

Birth length is 80–90 cm. Adults are about 2.5 m long and weigh 110 to 140 kg. Sexual maturity is reached at 10 years in females and 12 years in males. The average lifespan is around 40 years.

Population and distribution

The pantropical spotted dolphin, as its name implies, is widely distributed around tropical and marine waters from 40°N and 40°S and is one of the most common dolphin species in the Atlantic and Indian oceans.[6]The total world population is in excess of three million — the second-most abundant cetacean after the bottlenose dolphin — of which two million are found in the eastern Pacific. However, this represents a decrease from at least 7 million since the 1950s.

The pantropical spotted dolphin is the most common cetacean species observed within the Agoa Sanctuary, located in the Lesser Antilles in the eastern Caribbean.[6] Because it is common within the sanctuary it is considered a resident species; however, no research has been carried out to estimate its population status and movement patterns between islands.[6]

Centres of highest population density are the shallow warmest waters (water temperature in excess of 25 °C). They also tend to concentrate where a high temperature gradient is found.

Appearances of vagrancy in the Levantine Basin of the Mediterranean Sea through Suez Canal is expected.[8]

Human interaction

Dolphin swimming ahead of the NOAA Ship Rude

The pantropical spotted dolphin's propensity for associating with tuna, particularly in the eastern Pacific, has in recent history been a very real danger. In the 1960s and 1970s, fishermen would capture thousands of dolphin and tuna at once using purse seine nets. The dolphins all died. Over a period of about 25 years, 75% of this region's population, and over half the world's total were wiped out. The issue has received wide public attention. Many major supermarkets have found it economically expedient to use tuna suppliers whose fisherman catch tuna by more discriminatory means, and thus advertise their tuna product as dolphin-friendly. Some such products are approved by the Whale and Dolphin Conservation Trust.[9]

Negative impacts from fishing activities remain, despite broad "dolphin-safe" practices]]. Instead of reducing numbers through direct mortalities, fishing activities have disrupted the reproductive output of the northeastern pantropical spotted dolphin. The fishing had a negative impact on calf survival rates and/or birth rates. This could be caused when fishing operations separate mothers from their suckling calves, interfere with the conception or gestation of calves, or a combination of the two.[10]

Major threats

The eastern Pacific populations of pantropical spotted dolphins are divided into 3 units – coastal and 2 offshore populations, northeastern and western-southern.[11] Just under 5 million dolphins were killed between 1959 and 1972. 3 million of these were from the northeastern offshore population unit.[12] Since that time, this subpopulation has been the slowest to recover, if it is truly recovering at all.[13] Natural mortalities are occurring as well, but they are difficult to estimate.[14]

The major threat to Stenella attenuata is individuals killed as by-catch in fisheries.[11] Tuna fishermen follow pantropical spotted dolphins in order to find and catch fish. The height of incidental killings was in the 1960s and 1970s.[2] Tuna fishermen from the 1950s to the 1980s in the eastern Pacific killed massive numbers of dolphins, most of which were offshore spotted dolphins.[2]

Another threat to this species is gillnet fisheries in Australia, North Pacific (central and northern areas), Peru, Ecuador, Japan, and Philippines.[2] Trawls in West Africa and long-lining in the Central Atlantic likewise pose significant threats to these species.[11] Small directed catches in other parts of the world are not as well documented. There is a large-mesh pelagic driftnet fishery of eastern Taiwan where a large number of dolphin killings are suspected.[2] The exact number of deaths due to this fishery is unknown.

Japan catches pantropical spotted dolphins for human consumption.[2] The average catch between 1995 and 2004, was 129 animals annually.[15] Pantropical spotted dolphins are the preferred species for consumption in Taiwan.[2]

Conservation actions

The eastern tropical Pacific and Southeast Asian populations of the pantropical spotted dolphin are listed in Appendix II[16] of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As the pantropical spotted dolphin can be divided into three subspecies, studies of these distinct populations would be needed to assess conservation efforts.[17]

In addition, the pantropical spotted dolphin is covered by the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia (Western African Aquatic Mammals MoU) and the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MoU).[18] The U.S. Marine Mammal Protection Act was established in 1972. U.S. Fishing vessels have since reduced dolphin by-catch deaths by 95%.[19] The U.S. Marine Mammal Protection Act lists the northeastern and coastal stocks as “Depleted.”[20]

Dolphin deaths have greatly decreased since the establishment of the Inter-American Tropical Tuna Commission (IATTC). The Commission set mortality limits on the international fleet. In 2005, only 373 spotted dolphin deaths were observed.[21]

Dolphin populations are able to grow at 4% per year,[22] but the pantropical spotted dolphin populations did not improve or worsen between 1979 and 2000.[23] The population has not recovered, even though 30 years of management has been in effect.

Although the US and international fishing agencies have reduced dolphin bycatch significantly, the northeastern subpopulation is not showing strong signs of recovery.[13] This lack of recovery of the subpopulations of the pantropical spotted dolphins could be due to the following reasons: calf separation, orphaning, fishery stress, under-reported mortality, and ecosystem change.[2] Observed deaths of these dolphins could be under-reported because small vessels do not have observers, observers do not see the net constantly at all times, injured dolphins die after observation, and dead individuals are not always reported.[13]

See also

Footnotes

References

  1. ^ Mead, J. G.; Brownell, R. L. Jr. (2005). "Order Cetacea". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. pp. 723–743. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ^ a b c d e f g h Kiszka, J.; Braulik, G. (2018). "Stenella attenuata". IUCN Red List of Threatened Species. 2018: e.T20729A50373009. doi:10.2305/IUCN.UK.2018-2.RLTS.T20729A50373009.en. Retrieved 19 November 2021.
  3. ^ "Appendices | CITES". cites.org. Retrieved 14 January 2022.
  4. ^ "List of Marine Mammal Species and Subspecies|May 1 2022". Society for Marine Mammalogy. Retrieved 1 May 2022.
  5. ^ Rice, DW (1998). Marine mammals of the world: Systematics and distribution. Society for Marine Mammalogy. p. 108. ISBN 978-1-891276-03-3.
  6. ^ a b c d e Courtin, Baptiste (April 2022). "Insights on the residency status and inter-island movement patterns of pantropical spotted dolphins Stenella attenuata in the Agoa Sanctuary, Eastern Caribbean". [Latin American Journal of Aquatic Mammals]. 17: 1427–1471 – via www.lajamjournal.org/index.php/lajam/article/download/1427/471.
  7. ^ Pires, Clara R.; Rossi-Santos, Marcos R.; Paro, Alexandre D.; Wedekin, Leonardo L. (1 May 2021). "Whistles of the pantropical spotted dolphin (Stenella attenuata) in Santos Basin, western South Atlantic Ocean". The Journal of the Acoustical Society of America. 149 (5): 3241–3249. doi:10.1121/10.0004950. ISSN 0001-4966. PMID 34241090. S2CID 235775950.
  8. ^ Update on the Cetacean Fauna of the Mediterranean Levantine Basin
  9. ^ The Illustrated Encyclopedia Of North American Mammals: A Comprehensive Guide to Mammals of North America. MobileReference. 2009. ISBN 9781605012797.
  10. ^ University of California, San Diego, Scripps Institution of Oceanography (24 November 2008). "Dolphin Population Stunted by Fishing Activities". Newswise, Inc. Retrieved 24 September 2012.{{cite news}}: CS1 maint: multiple names: authors list (link)
  11. ^ a b c Perrin, William F. "Stenella attenuata." Mammalian species(2001): 1-8.
  12. ^ Wade, P. R. "Revised estimates of incidental kill of dolphins(Delphinidae) by the purse-seine tuna fishery in the eastern Tropical Pacific, 1959-1972." Fishery Bulletin 93.2 (1995): 345-354
  13. ^ a b c Gerrodette, Tim, and Jaume Forcada. "Non-recovery of two spotted and spinner dolphin populations in the eastern tropical Pacific Ocean." Marine Ecology Progress Series 291 (2005): 1-21.
  14. ^ Perrin, William F. "Pantropical spotted dolphin: Stenella attenuata." Encyclopedia of Marine Mammals (Second Edition). 2009. 819-821.
  15. ^ Kasuya, Toshio. "Japanese whaling and other cetacean fisheries (10 pp)." Environmental Science and Pollution Research-International 14.1 (2007): 39-48.
  16. ^ "Appendix II Archived 11 June 2011 at the Wayback Machine" of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008. Effective: 5 March 2009.
  17. ^ Convention on Migratory Species page on the Pantropical spotted dolphin Archived 3 February 2007 at the Wayback Machine, Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia
  18. ^ Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region
  19. ^ Baur, DONALD C., MICHAEL J. Bean, and MICHAEL L. Gosliner. "The laws governing marine mammal conservation in the United States." Conservation and management of marine mammals. Smithsonian Institution Press, Washington, DC (1999): 48-86.
  20. ^ Read, Andrew J., and Paul R. Wade. "Status of marine mammals in the United States." Conservation Biology 14.4 (2000): 929-940.
  21. ^ Bayliff, W. H. "Organization, functions, and achievements of the Inter-American Tropical Tuna Commission (IATTC Special Report No. 13)." Retrieved form https://www.iattc.org/SpecialReportsENG.htm Google Scholar (2001).
  22. ^ Reilly, STEPHEN B., and J. Barlow. "Rates of increase in dolphin population size." Fishery Bulletin 84.3 (1986): 527-533.
  23. ^ Lennert-Cody, Cleridy E., Stephen T. Buckland, and FERNANDA FC MARqUES. "Trends in dolphin abundance estimated from fisheries data: a cautionary note." Journal of Cetacean Research and Management 3.3 (2001): 305-320.
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Pantropical spotted dolphin: Brief Summary

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The pantropical spotted dolphin (Stenella attenuata) 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. In the 1980s, the rise of "dolphin-friendly" tuna capture methods saved millions of the species in the eastern Pacific Ocean and it is now one of the most abundant dolphin species in the world.

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Distribution

provided by World Register of Marine Species
all oceans, between about 40°N and 40°S

Reference

van der Land, J. (ed). (2008). UNESCO-IOC Register of Marine Organisms (URMO).

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Distribution

provided by World Register of Marine Species
distributed worldwide in tropical and some sub-tropical oceans

Reference

North-West Atlantic Ocean species (NWARMS)

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Habitat

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oceanic

Reference

van der Land, J. (ed). (2008). UNESCO-IOC Register of Marine Organisms (URMO).

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IUCN Red List Category

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Least Concern (LC)

Reference

IUCN (2008) Cetacean update of the 2008 IUCN Red List of Threatened Species.

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Perrin, William [email]