Tag: Ocean

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The Ross ice shelf, in Antarctica, has been found to move

The Ross ice shelf is vast, covering 182,000 square miles, it is only slightly smaller than France, and yet a study has shown, that the whole ice shelf can move 40 cm in just 10 minutes. These were generally caused by slips in the Whillans Ice Sheet, which is one of just a few ice flows into and through the area.

The whole shelf was found to move 6-8cm once or twice a day, triggered by these flows moving. This could be the cause of both icequakes, and fractures running through the ice (fractures are important, as they make it more likely that a section of the ice will break off the edge of Antarctica and head into the ocean. While this ice can, on occasion survive a long time – A23a broke of Antarctica in 1986 and has been floating free for much of the time since (except for a decade or so when it grounded); it was estimated to be 400m thick and weigh in at nearly 1 trillion tonnes.

This is a problem for a simple reason. Unlike the north pole, there is land under the ice in Antarctica. This means that while in the north pole, the ice sheet is already in the sea, so its melting cannot increase sea level, Antarctic ice all does increase sea levels.

The Ross ice shelf is known to have collapsed 120,000 years ago during the last interglacial period, and contains enough ice to raise sea levels by 11.5m (this would also cause another 2m of sea level rise because of the glaciers which would no longer be held back).

A Dutch startup, is trialling mitigating this in the Arctic, by pumping sea water onto the ice. This then freezes, thickening the ice. It is possible that this might work in the short term, however, what is clear, is that the only long-term solution, is to stop burning fossil fuels, so as to halt the heating of the earths climate.

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Great white sharks separated into 3 district populations 200,000 years ago – and have Orca stopped hunting the South African population?

These 3 groups do not intermix, and only very seldom, interbreed. These populations are found in the Southern Pacific, Northern Pacific and the North Atlantic and Mediterranean.

This naturally means that the great white sharp is far more at risk of extinction, than if all the great white sharks in the worlds oceans could interbreed.

These areas appear to be bounded by great ocean currents, which are rarely crossed. This is a problem, as if an individual population is lost, it makes it far more likely that distinct genetic information could be lost with it – take the Mediterranean great while shark population, which has seen a dramatic population decline from historic numbers, estimated at between 52% and 96% (areas like the Maramara sea, are known to have lost 96% of their population) depending on which study you read.

This makes local conservation far more essential, and we need to be careful to not loose any individual populations. There has been a great deal of worry for the great white shark population around South Africa, as they pretty much vanished in 2017, but appear to have returned in 2024. The disappearance of the great white was attributed to 2 orca which had become expert in hunting and killing these sharks – it should be remembered, that while great whites are often at the top of the food chain, they are hunted for food by orca. Whether these orca have gone back to eating something else, hence the great white shark return, is a question that does not appear to have been answered as yet.

La Plata Dolphin

La Plata dolphin

Also known as franciscana or toninha, this is a river dolphin, found in the coastal waters of southeastern South America. Being a member of the Inioidea family, it is only capapable of living in saltwater, so is found in the ocean and saltwater estuaries. This has an unfortunate effect of being around the mouth of rivers, and therefore being effected by all the pollutants picked up the whole route of the river.

It is also regularly noted, that this run-off kills off the fish which this dolphin species requires for survival. It was first described in 1844.

It is thought that fewer than 30,000 of these animals remain in the wild.

There is some tourism around this species. As we get links they will appear beneath the news section below.

Beaked whales

Beaked whales

Beaked whales are a fascinating wide-ranging family. There are 24 species, but they spend much of their time in the ocean depths, and are capable of holding their breath for up to 3 hours.

More amazingly, it appears that some species might only spend several minutes at the surface before returning to the depths. Now, while this 3 hours record dive is repeatable is a big question. Assuming the beaked whale was capable of repeating this 8 times in a 24 hour period, we would be talking about a species which spends only 1% of its time at the surface. Given their shape also allows them to keep an incredibly low profile, even at the surface – and we do not know how many of them there are, it makes it clear how hard it would be to spot one.

If you could sit in one place, in the ocean for 24 hours, and have a whale repeatedly return to the surface for 2 minutes, half a mile away, it would not be hard to miss the animal.

Please note, where I have found a video, it is in line with the correct image. Before you reach all these species, there is an amalgamated news section for all beaked whales.

We are eager to support tourism of these species, but given they are seen so rarely, there is not a great deal of tourism connected to them. However, we will happily list anyone who does work in tourism and sees one of these even once (we will also list you on pages for cetaceans that you see more regularly.

Arnoux beaked whale Genus Beradius

Also known as the southern 4 toothed whale, southern beaked whale, New Zealand beaked whale, southern giant bottlenose whale and southern porpoise whale is one of the species of Berardius. This species and the one below, is so similar that only genetic evidence and the huge distance between them convinced people they were separate species. 

Little is known about them, because they are encountered so rarely

Baird Beaked whale Genus Beradius

Also known as the northern giant bottlenose whale, North Pacific bottlenose whale, giant four-toothed whale, northern four-toothed whale and the North Pacific four-toothed whale, is a species of whale from the genus Beradius. It is the second largest toothed whale after the Sperm Whale

Sato Beaked whale Genus Beradius

This whale was only recognized as a separate species on the basis of mtDNA. Its beak is usually only around 4% of body length. The name comes from the researcher who defined it (from pictures on land.

They generally have many scars, which are easy to see, as their skin is dark and the scars light to white.

Its classed as near threatened, though its hard to know.

Subfamily Hyperodontinae, Genus Hyperoodon – bottlenose whales, northern bottlenose whale The northern bottlenose whale was hunted heavily by Norway and Britain in the 19th and 20th centuries. It is capable of diving incredibly deep, with recorded dives reaching 2339m, and has been timed staying under water for 130 minutes. The northern bottlenose whale is endemic to the North Atlantic Ocean< and populations are found in the deep (500 m) cold subarctic waters of the Davis Strait, Labrador Sea, Greenland Sea, Barents Sea, , but can range as far south as Newfoundland and Nova Scotia. As of 2017, the population in the North East Atlantic is estimated to be between 10,000 and 45,000.

Subfamily Hyperodontinae, Genus Hyperoodon – bottlenose whales, Southern bottlenose whale

The southern bottlenose whale is a species of whale, in the Ziphiid family, one of two members of the genus Hyperoodon. Seldom observed, the southern bottlenose whale is resident in Antarctic waters. The species was first described by English zoologist William Henry Flower in 1882, based on a water-worn skull from Lewis Island, in the Dampier Archipelago, Western Australia. They live in deep ocean waters over 1000 meters.

Gnerally their dives last 15-40 minutes, but it is unclear if they would be capable of diving for as long as the northern species. There are no population estimates, though they make up 90% of ziphiid sightings in Antarctic waters.

Subfamily Hyperodontinae, Genus Indopacetus, Tropical bottlenose whale

The tropical bottlenose whale, also known as the Indo-Pacific beaked whale or Longman’s beaked whale, was considered to be the world’s rarest cetacean until recently, but the spade-toothed whale now holds that position. As of 2010, the species is now known from nearly a dozen strandings and over 65 sightings. This is the only species in its genus.

Given how rarely they are sighted, they have not been hunted, though they have been killed accidently.

Andrews' beaked whale

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales, Andrews Beaked whale

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales Blainvilles beaked whale

Blainville's beaked whale

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales Deraniyagala beaked whale

The Deraniyagala beaked whale is so rare, I have been unable to find a video to place here

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Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales, Gervaiss beaked whale

Gervais's beaked whale
Ginkgo-toothed beaked whale

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales,

Ginkgo-toothed beaked whlae

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales, grey beaked whale

grey beaked whale
Hector's beaked whale

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales, Hectors beaked whale

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales, Hubbs Beaked whale

Hubbs' beaked whale
Perrin's beaked whale

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales, Perrins beaked whale

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales, Pygmy beaked whale

Pygmy beaked whale
Ramari's beaked whale

Subfamily Hyperodontinae, Genus Mesoplodon, mesoplodont whales

Subfamily Hyperodontinae

Sowerby's beaked whale
Spade-toothed whale

Subfamily Hyperodontinae

Subfamily Hyperodontinae

Stejnegers beaked whale
Strap-toothed whale

Subfamily Hyperodontinae

Subfamily Hyperodontinae

True's beaked whale

White-beaked dolphin

White beaked dolphin

The white-beaked dolphin  is a marine mammal belonging 

to the family Delphinidae (oceanic dolphins) in the sub order Odontoceti (toothed whales). Their distribution is shown in the map.

The white-beaked dolphin is endemic to the cold temperate and subarctic waters of the North Atlantic Ocean, most commonly in seas less than 1,000 m (3,300 ft) deep. Due to the fact they are not fully adapted to Arctic conditions, they are more vulnerable to predators, most notably polar bears. Within this wider region, white-beaked dolphins are most commonly found in four locales: on the Labrador Shelf close to southwestern Greenland, around Iceland, off the northern and eastern coasts of Britain, and off the coast of Norway. In the Faroe Islands between Iceland and the United Kingdom the White-beaked dolphin is at risk of being hunted during drive catches of the long-finned pilot whales. They may also be incidentally trapped in the purse-sein and trawl nets of the area. There are no recognised subspecies.

The dolphin may easily be misidentified as the Atlantic white-sided dolphin, although the white-beaked is commonly found further north. The white-beaked dolphin is also typically larger, and does not have yellow streaks on its side.

Below is a video (no sound) of them filmed under water off the coast of the UK. Northern parts of the UK have populations, including Lyme bay and areas around the hebrides.

They are thought to number 100,000, so are listed as least concern.

Common Dolphin

Common Dolphin

  • The most abundant cetacean in the world, with around 6 million (it should be noted that there are 1350 humans in the world, for every individual common dolphin).

Despite this fact and its name, the common dolphin is not thought of as the model dolphin (that honour goes to the bottlenose dolphin due to its popular appearances in aquaria and the media). It did, however, feature heavily in Ancient Greek and Roman art and culture, most notably in a mural painted by the Greek Minoan civilization.

It is currently the only member of the genus Delphinus. The common dolphin belongs to the subfamily Delphininae, making this dolphin closely related to the three different species of bottlenose dolphins, humpback dolphins, striped dolphins, spinner dolphins, clymene dolphin, spotted dolphins, fraser’s dolphin and the tucuxi and guiana dolphin.[5] The common dolphin was originally categorized into two different species (now thought to be ecotypes), the short-beaked common dolphin and the long-beaked common dolphin. However, recent evidence has shown that generally long-beaked dolphins of this species have originated from the short-beaked population, and therefore there is no close links between different long-beaked dolphins in any part of the world.

Currently, the common dolphin is divided into four subspecies:

  • D. d. delphis, the nominate subspecies
  • D. d. bairdii, the Eastern North Pacific long-beaked common dolphin
  • D. d. ponticus, the Black Sea common dolphin
  • D. d. tropicalis, the Indo-Pacific common dolphin

A number of fossils were erroneously placed in the same genus, but this has since been corrected. 

Common dolphins can live in aggregations of hundreds or even thousands of dolphins,though are often seen in groups numbering several hundred individuals (with subgroups consisting of 20-30 individuals). Occasionally, different groups will come together to form mega-pods which can consist of over 10,000 dolphins – quite a site to witness. Genetic studies in the Northeast Atlantic suggest that common dolphin pods generally do not consist of close kin, but rather of members that are not closely related. Unlike many delphinids, common dolphins do not live in a matriarchal society. That being said, closely related individuals are usually found in similar geographical locations fairly consistently, providing evidence that this species displays site fidelity (at least in the North-eastern Atlantic). Male common dolphins display greater site fidelity in relation to their kin than females.

Common dolphin pod structure often consists of nursery pods (which includes females and calves), bachelor pods (consisting of all males) and mixed groups of males and females, including sub-adults and calves. Genetic evidence seems to indicate that common dolphins live in fission-fusion societies, where dolphins form pods that are not necessarily stable and do not necessarily consist of related individuals. It is not known if common dolphins form lifelong bonds with other individuals  like the long-term male alliances seen in bottlenose dolphins.

There is some evidence that common dolphins use signature whistles, similar to that of the bottlenose dolphin. These whistles are believed to serve as an acoustic label the dolphin equivalent of a name.  It takes approximately 1 year for a calf to learn its signature whistle after which it remains stable for the rest of a dolphin’s life.

In South Africa, as many as 29 common dolphin signature whistle types were detected. However, it was difficult to determine if each dolphin had its own signature whistle due to the vast number of dolphins present (over 1,000) and anthropogenic background noise. Additionally, considering the vast number of dolphins present and  taking into account their feeding and diving behaviour, it appears that common dolphin signature whistles are also used for group cohesion. Another hypothesis for the function of signature whistles, is that they serve as a beacon for lost individuals.

Common dolphins sometimes associate with other dolphin species, such as pilot whales (note, not actually whales). In the Gulf of Corinth, common dolphins frequently display mixed species association, especially with striped and Rissos’ dolphins. Over one third of all dolphin sightings in the gulf consisted of mixed species associations that partially consisted of common dolphins. In mixed species associations, the ratio of striped to common dolphins ranged from 6-11:1. When Rissos’ dolphins were present (there would usually be only one or two individuals), it appeared that much of their scars were the result of interactions between striped and spinner dolphins. In much of the interactions, the Rissos’ dolphins would chase and herd the common dolphins toward the boat, while the common dolphins would try and swim under the Rissos’ dolphin. When groups of common and striped dolphins would charge at each other, the Rissos’ dolphin would chase the striped dolphins. Sometimes these interactions appeared to be playful, and at other times aggressive. Synchronized swimming and surfacing was commonly observed. These interactions take place in the deepest part of the Gulf, furthest from shore and usually consist of a total of 60 dolphins from all three species.

There have been 15 cases of common dolphin and striped dolphin hybrids being recorded. Genetic and observational evidence has demonstrated that the hybrids are fertile and are capable of not only reproducing with other hybrids, but are capable of reproducing with each of the parent species. Striped dolphins have been known to mate with other dolphins, as the Clymene dolphin is the result of hybrid speciation between striped and spinner dolphins. However, this is unlikely to happen with common dolphins, as their population in the Gulf of Corinth is too low. Common dolphins and bottlenose dolphins have been known to interbreed in captivity. There is one confirmed case of a hybrid between a bottlenose and common dolphin in Southern Spain, an important feeding ground for both species. The mother was a female bottlenose dolphin (dubbed as Billie) who has spent 10 years within a common dolphin pod. Billie was observed assisting common calves reach the surface at three different intervals and would babysit the calves after the mother went through labour. They have also been observed bow riding on baleen whales, and they also bow ride on boats. They are fast swimmers and breaching behaviour and aerial acrobatics are common with this species. They are also known to display altruistic behaviours to support injured members.

The short-beaked common dolphin is pregnant for 10 to 11 months. The new-born calf has a length of 70 to 100 centimetres (2.3 to 3.3 ft) and weighs about 10 kilograms. For the Black Sea population, weaning occurs at between five and six months, but occurs later (up to about 19 months) in other areas. Typical interbirth interval ranges from one year for the Black Sea population to three years for eastern Pacific Ocean populations. Age of sexual maturity also varies by location, but can range between two and seven years for females and three and 12 years for males. No evidence exists of any major reproductive differences between the two species. In captivity, the long-beaked common dolphin has hybridized with the common bottlenose dolphin . One of the hybrids has been bred back to a bottlenose dolphin, demonstrating such hybrids are fertile.

Find our news section below this video of a megapod of common dolphins

Spinner Dolphin

Spinner dolphin

The spinner dolphin (also known as the long-snouted dolphin (distinguishing it from the Clymene dolphin – which is often called the short snouthed spinner dolphin) is a small dolphin found in off-shore tropical waters around the world. It is famous for its spinning  along its length, as it leaps from the water. It is a member of the family Delphinidae of toothed whales.

The four named subspecies are:

  • Eastern spinner dolphin, found from the tropical eastern Pacific.
  • Central American or Costa Rican spinner dolphin, also found in the tropical eastern Pacific.
  • Gray’s or Hawaiian spinner dolphin, from the central Pacific Ocean around Hawaii but represents a mixture of broadly similar subtypes found worldwide.
  • Dwarf spinner dolphin, first found in the Gulf of Thailand.

The species, though, displays greater variety than these subspecies might indicate. A hybrid form characterized by its white belly inhabits the eastern Pacific. Other less distinct groupings inhabit other oceans.The species name comes from the Latin word for “long-beaked.”

Spinner dolphins are small cetaceans with a slim build. Adults are 129–235 cm long and weigh 23–79 kg. This species has an elongated rostrum and a triangular or subtriangular dorsal fin. Spinner dolphins generally have three colours, one on the dorsal fin, one on the underside and one on the upper-side. Also, a dark band runs from the eye to the flipper, bordered above by a thin, light line. However, the spinner dolphin has more geographic variation in form and coloration than other cetaceans. In the open waters of eastern Pacific, dolphins have relatively small skulls with short rostra. A dwarf form of spinner dolphin occurs around southeast Asia. In these same subspecies, a dark dorsal cape dims their tripartite colour patterns Further offshore, subspecies tend to have a paler and less far-reaching cape.] In certain subspecies, some males may have upright fins that slant forward.[8] Some populations of spinner dolphin found in the eastern Pacific have backwards-facing dorsal fins, and males can have dorsal humps and upturned caudal flukes.

The spinner dolphin lives in nearly all tropical and subtropical waters between 40°N and 40°S. The species primarily inhabits coastal waters, islands, or banks. However, in the eastern tropical Pacific, spinner dolphins live far from shore. Some studies suggest they use different areas at different times of the year.

The spinner dolphin feeds mainly on small mesopelagic fish, squids, and sergestid shrimps, and will dive 200–300 m to feed on them. Spinner dolphins of Hawaii are nocturnal feeders and forage in deep scattering layers, which contain many species. The dwarf spinner dolphin may feed mostly on benthic fish in reefs and shallow water. Off Oahu, Hawaii, spinner dolphins forage at night and cooperatively herd their prey into highly dense patches. They swim around the prey in a circle and a pair may swim through the circle to make a catch. Spinner dolphins are in turn preyed on by sharks. Other possible predators include the killer whale, the false killer whale, the pygmy killer whale and the short-finned pilot whale. They are susceptible to parasites, and are known to exhibit both external ones like barnacles and remoras as well as internal parasites.


Due to the spinner dolphin foraging and feeding at night, in certain regions, such as Hawaii and northern Brazil, dolphins spend the daytime resting in shallow bays near deep water. Spinner dolphins rest as a single unit, moving back and forth slowly in a tight formation but just out of contact with one another. These resting behaviours are observed for about four to five hours daily. During rest periods, spinner dolphins rely on vision rather than echolocation. At dusk, they travel offshore to feed. They travel along the shore during foraging trips, and the individuals that occupy the same bay may change daily. Some individual dolphins do not always go to a bay to rest; however, in Hawaii, dolphins do seem to return to the same site each trip.

Spinner dolphins live in an open and loose social organization. The spinner dolphins of Hawaii live in family groups, but also have associations with others beyond their groups. Mothers and calves form strong social bonds. Spinner dolphins seem to have a promiscuous mating system, with individuals changing partners for up to some weeks. A dozen adult males may gather into coalitions. Vocalizations of spinner dolphins include whistles, which may be used to organize the school, burst-pulse signals, and echolocation clicks. The spinner dolphin has a 10-month gestation period, and mothers nurse their young for one to two years. Females are sexually mature at four to seven years, with three-year calving intervals, while males are sexually mature at seven to 10 years. Spinner dolphins live for about 20-25 years old. Breeding is seasonal, more so in certain regions than others.

Although most spinner dolphins are found in the deeper waters offshore of the islands, the rest of the Hawaiʻi population has a more coastal distribution. During daytime hours, the island-associated stocks of Hawaiian spinner dolphins seek sanctuary in nearshore waters, where they return to certain areas to socialize, rest, and nurture their young.

They get their name for their spinning jumps, a spinner dolphin comes out of the water front first and twists its body as it rises into the air. When it reaches its maximum height, the dolphin descends back into the water, landing on its side. A dolphin can make two to seven spins in one leap; the swimming and rotational speed of the dolphin as it spins underwater affects the number of spins it can do while airborne. These spins may serve several functions. Some of these functions are believed by experts to be acoustic signalling or communication. Another reason is to remove ectoparasites such as remoras. Dolphins may also make nose-outs, tail slaps, flips, head slaps, “salmon leaps”, and side and back slaps.

The protected status of spinner dolphins are CITES Appendix II and Marine Mammal Protection Act (MMPA) protected throughout its range as well as MMPA depleted in its eastern stock. Tens of thousands of spinner dolphins, mostly eastern and white-bellied varieties, were killed in the 30 years after purse seine fishing for tuna began in the 1950s; The process killed probably half of all eastern spinner dolphins. They have also been contaminated by pollutants such as DDT and PCBs. Spinner dolphins, as with other species affected by ETP tuna purse-seine fishing, are managed nationally by the coastal countries and internationally by the IATTC. The IATTC has imposed annual stock mortality limits on each purse seine and promulgated regulations regarding the safe release of dolphins. The eastern tropical Pacific and Southeast Asian populations of the spinner dolphin are listed on Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), since they have an unfavourable conservation status or would benefit significantly from international co-operation organized by tailored agreements. In addition, the spinner dolphin is covered by 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). Spinner dolphins are susceptible to disease and two of the recorded diseases within them are toxoplasmosis and cetacean morbillivirus. The number of cases reported however is fairly low in the species.

Spinner dolphins in Hawaii receive multiple daily visits to their near-shore resting grounds, with boats taking people out daily to snorkel and interact with the local dolphin population. Such activities are increasingly coming under criticism on the grounds of possible harm to the dolphins, and efforts are being made both to educate the public in order to minimise human impact on the dolphins, and to bring in regulations to govern these activities. In 2023, 33 swimmers were arrested for reportedly harassing dolphins off the coast of the Big Island of Hawaii. The swimmers reportedly broke federal law by swimming within 45 meters (50 yards) of the dolphins. The ban went into effect in 2021 due to dolphins not getting enough rest during the day to forage for food at night. The swimmers were caught by drone footage pursuing the dolphins as they tried to escape.

We are eager to work with people who run boats to see these animals – provided they are run with due care for the animals. Do get in touch, or fill in a form you will find in ‘List your wild place’ at the top of the page (or click here).

Indo-pacific bottlenose dolphin

Indo-Pacific Bottlenose dolphin

The Indo-Pacific bottlenose dolphin is a species of Bottlenose dolphin. This dolphin grows to 2.6 m long, and weighs up to 230 kg . It lives in the waters around northern Australia , South China, the Red Sea, and the eastern coast of Africa. Its back is dark grey and its underside is lighter grey or nearly white with grey spots. The Indo-Pacific bottlenose dolphin is usually smaller than the Common bottlenose dolphin, has a proportionately longer Rostrum, and has spots on its belly and lower sides. It also has more teeth than the common bottlenose dolphin â€” 23 to 29 teeth on each side of each jaw compared to 21 to 24 for the common bottlenose dolphin.

Much of the old scientific data in the field combine data about the Indo-Pacific bottlenose dolphin and the common bottlenose dolphin into a single group, making it effectively useless in determining the structural differences between the two species. The IUCN lists the Indo-Pacific bottlenose dolphin as “near threatened” in their Red List of endangered species.

Until 1998, all bottlenose dolphins were considered members of the single species Tursiops truncatus. In that year, the Indo-Pacific bottlenose dolphin was recognized as a separate species. Both species are thought to have split during the mid-Pleistocene, about 1 million years ago. Some evidence shows the Indo-Pacific bottlenose dolphin may actually be more closely related to certain dolphin species in the Delphinus (genus), especially the “Atlantic spotted dolphin”, than it is to the common bottlenose dolphin. However, more recent studies indicate that this is a consequence of reticulate evolution (such as past hybridization between Stenella and ancestral Tursiops and incomplete lineage sorting, and thus support truncatus and T. aduncus belonging to the same genus. Burrunan dolphin T. (aduncus) australis has been alternately considered its own species, a subspecies of T. truncatus, or a subspecies of T. aduncus. Following the results of a 2020 study, the American Society of Mammologists presently classifies it as a subspecies of T. aduncus. The same study delineated 3 distinct lineages within T. aduncus which could each be their own subspecies: an Indian Ocean lineage, an Australasian lineage, and the Burrunan dolphin. The Society for Marine Mammalogy does not recognize the Burrunan dolphin as a distinct species or subspecies, citing the need for further research. Indo-Pacific bottlenose dolphins are very similar to common bottlenose dolphins in appearance. Common bottlenose dolphins have a reasonably strong body, moderate-length beak, and tall, curved dorsal fins; whereas Indo-Pacific bottlenose dolphins have a more slender body build and their beak is longer and more slender. 

Indo-Pacific bottlenose dolphins feed on a wide variety of fish Cephalopod, Squid, researchers looked at the feeding ecology of Indo-Pacific bottlenose dolphins by analysing the stomach contents of ones that got caught in the gillnet fisheries off Zanzibar, Tanzania.  Indo-Pacific bottlenose dolphins live in groups that can number in the hundreds, but groups of five to 15 dolphins are most common. 

In some parts of their range, they spend time with the common bottlenose dolphin and other dolphin species, such as the humpback dolphin. The peak mating and calving seasons are in the spring and summer, although mating and calving occur throughout the year in some regions. Gestation period is about 12 months. Calves are between 0.84 and 1.5 Meters, and weigh between 9 and 21kg. The calves are weaned between 1.5 and 2.0 years, but can remain with their mothers for up to 5 years, some mothers will give birth again, shortly before the 5 years are up. 

In some parts of its range, this dolphin is subject to predation by sharks. 

Its lifespan is more than 40 years. Indo-Pacific bottlenose dolphins located in Shark Bay, Australia, have been observed using sponges as tools in a practice called “sponging”. A dolphin breaks a marine sponge off the sea floor and wears it over its rostrum, apparently to probe substrates for fish, possibly as a tool. Spontaneous ejaculation in an aquatic mammal was recorded in a wild Indo-Pacific bottlenose dolphin near Mikura Island, Japan, in 2012. Indo-Pacific bottlenose dolphins have been observed to swim near and rub themselves against specific types of corals and sponges. A team of scientists followed up on this behaviour and discovered metabolites with antibacterial, antioxidative, and hormonal activities in the corals and sponges, suggesting that they might be used by the dolphins to treat skin infections. its near-shore distribution, though, makes it vulnerable to environmental degradation, direct exploitation, and problems associated with local fisheries. 

The major predators of this species are typically sharks, and may include humans, killer whales, and sting rays. In the early 1980s, many were deliberately killed in a Taiwanese driftnet fishery in the Arafura Sea, off north western Australia. Large-mesh nets set to protect bathers from sharks in South Africa and Australia have also resulted in a substantial number of deaths. Gillnets are also having an impact, and are a problem throughout most of the species’ range.

These small cetaceans are commonly found in captivity, causing conservation concerns, including the effects of removing the animals from their wild populations, survival of cetaceans during capture and transport and while in captivity, and the risks to wild populations and ecosystems of accidentally introducing alien species and spreading epizootic diseases, especially when animals have been transported over long distances and are held in sea pens.

Bottlenose dolphins are the most common captive cetaceans on a global scale. Prior to 1980, more than 1,500 bottlenose dolphins were collected from the United States, Mexico, and the Bahamas, and more than 550 common and 60 Indo-Pacific bottlenose dolphins were brought into captivity in Japan. By the late 1980s, the United States stopped collecting bottlenose dolphins and the number of captive-born animals in North American aquaria has increased from only 6% in 1976 to about 44% in 1996. South Korea, in the 2010s, environmental groups and animal protection groups led a campaign ko:2013 to release southern bottlenose dolphins illegally captured by fishermen and trapped in Jeju Island.

In a study on three populations of Indo-Pacific bottlenose dolphins in Japan, the characteristics of acoustic signals are believed to be affected by the acoustic environments among habitats, and geographical variation in animal acoustic signals can result from differences in acoustic environments; therefore, the characteristics of the ambient noise in the dolphins’ habitats and the whistles produced were compared. Ambient noise was recorded using a hydrophone located 10 m below the surface and whistles were recorded by using an underwater video system. The results showed dolphins produced whistles at varying frequencies with greater modulations when in habitats with less ambient noise, whereas habitats with greater ambient noise seem to cause dolphins to produce whistles of lower frequencies and fewer frequency modulations. Examination of the results suggest communication signals are adaptive and are selected to avoid the masking of signals and the decrease of higher-frequency signals. They concluded ambient noise has the potential to drive the variation in whistles of Indo-Pacific bottlenose dolphin populations.

Small, motorized vessels have increased as a source of anthropogenic noise due to the rise in popularity of wildlife viewing such as whale watching. Another study showed powerboat approaches within 100 m altered the dolphin surface behaviour from traveling to milling, and changed their direction to travel away from the powerboat. When the powerboat left the area and its noise ceased, the dolphins returned to their preceding behaviour in the original direction.

In Shark Bay, Western Australia, on dolphin behavioural responses showed significant changes in the behaviour of targeted dolphins were found when compared with their behaviour before and after approaches by small watercraft. Dolphins in the low-traffic site showed a stronger and longer-lasting response than dolphins in the high-traffic site. These results are believed to show habituation of the dolphins to the vessels in a region of long-term vessel traffic. However, when compared to other studies in the same area, moderated responses, rather, were suggested to be because those individuals sensitive to vessel disturbance left the region before their study began. Although these studies do show statistical significance for the effects of whale-watching boats on behaviour, what these results mean for long-term population viability is not known. The Shark Bay population has been forecast to be relatively stable with little variation in mortality over time. The Indo-Pacific bottlenose dolphin populations of the Arafura and the Timor Sea are listed on Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals “Bonn Convention”. They are listed on Appendix II as they have an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements. The Indo-Pacific bottlenose dolphin is also covered by Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region Adelaide Dolphin Sanctuary “Marine protected area”  in the Australian state of South Australia Gulf St Vincent, which was established in 2005 for the protection of a resident population of Indo-Pacific bottlenose dolphins.

When we have links for viewing these species, they will appear below video and the news section

Fraser’s dolphins

Frasers Dolphin

Generally found in the deep waters of the Pacific Ocean, though also seen in Indian and Alantic dolphin. It is also known as the Sarawak dolphin. When fully grown it weighs around 200kg and around 2.75m in length. From a distance it can be confused with a striped dolphin which lives in these waters. Usually found in large groups from 100-1000. Below is an encounter between a large group of frasers dolphins and a sailing boat.

While sightings have become far more common in recent times, there is no global estimate for the numbers of this species, though the Southeast Asian species is listed Appendix 2 of CITES so clearly there is a need to keep close watch on this situation.

Spectacled porpoise

Spectacled Porpoise

This is a small to mid-sized porpoise found in the Southern ocean. It is a species with some of the least study, thought largely as a result of the incredible isolation.

The majority of what we know, has come from stranded animals, and the few sightings that have occured. The have no beak. It has small pectoral fins with rounded tips positioned far forward on the body, and a triangular dorsal fin. Males have larger and rounder dorsal fins.

It is thought to be found around the southern pole, from Patagonia, South Georgia, New Zealand.

Population size is unknown given how rarely they are spotted.

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