Common bottlenose dolphin (Tursiops truncatus)

General information:

The common bottlenose dolphin is the most widely known species because it is the species kept by most aquariums. Their bodies are of gray tones though the belly may be off-white or pinkish. They have round, stubby, bottle-shaped beaks and hence their common name, “bottlenose”. Bottlenose dolphins are relatively large with adults growing to around 3.7-3.8 m and up to 4 m long. They are widely spread throughout the tropical and temperate waters around the world.

A common bottlenose dolphin beached on Sheung Pak Nai in 1985

Hong Kong records:

The Common bottlenose dolphin appears to be the third most commonly-stranded cetacean species in Hong Kong after the finless porpoise and humpback dolphin. There have been a total of 12 dead common bottlenose dolphin strandings in Hong Kong since 1980 with the most recent case found on Tung Lung Island in 2003. There was also a live stranding in 1983 and two in 1986. And in 1994 and 1998, schools of dolphins were seen in waters just off Cape D' Aguilar and Po Toi respectively (but these cannot be confirmed to be common or Indo-Pacific common bottlenose dolphins).

Indo-Pacific bottlenose dolphin (Tursiops aduncus)

General Information:

The Common bottlenose dolphin was only very recently determined to be a separate species from the Indo-Pacific bottlenose. Scientists were long aware of differences between the two types but did not complete adequate analyses until the late 1990s to assign the two forms separate species status. Unlike the Common bottlenose, the Indo-Pacific bottlenose is only found around the coastal waters of the Indian and Pacific oceans. With dark ventral spotting or flecking, Indo-Pacific animals grow to around 2.6m which is somewhat smaller than the Common bottlenose. Apart from these differences, the two species look very much similar.

Hong Kong records:

In August 2004, an Indo-Pacific bottlenose carcass was found floating in the waters between Double Island and Crescent Island in Northeastern Hong Kong . And back in 1994 and 1998, schools of dolphins were seen in waters just off Cape D' Aguilar and Po Toi respectively (but these cannot be confirmed to be common or Indo-Pacific common bottlenose dolphins).

A pod of bottlenose dolphin spotted at Po Toi waters in 1998

Long-beaked common dolphin (Delphinus capensis)

General Information:

It is now generally accepted that there are two types of the dolphin genus Delphinus : a long-beaked form ( Delphinus capensis ) and a short-beaked form ( Delphinus delphis ). Hong Kong has records of sightings of the long-beaked type only which can grow to about 2.5m in length and have intricate color patterns. Their most distinctive feature is the yellowish-tan patch and the hour-glass pattern on the sides of the animals. Long-beaked common dolphin is an oceanic species and is gregarious, preferring to stay in groups of less than 30, although they have been found in groups of up to 1,000. They are extremely playful and like to ride the bow alongside big whales and ships.

Hong Kong records:

The first ever dolphin stranding in Hong Kong reported in January 1955 was said to be a short-beaked common dolphin ( Delphinus delphis ). But the specimen was subsequently lost and the species' type could not be confirmed from the photograph afterwards. The latest literature therefore considers the specimen an unidentified dolphin.

The first confirmed appearance of a long-beaked common dolphin in Hong Kong happened in May 1989 at Shap Long, south of Mui Wo. Three more carcasses of this species have been found since then, with the latest one entangled in a fishing net offshore of Po Toi Island in May 2004.

Live long-beaked dolphins have been sighted in Hong Kong a couple of times. In 1978, about 50 Long-beaked common dolphins were spotted in Victoria Harbour . Then on February 26, 2006 , one was seen at the typhoon shelter in Shau Kei Wan. The dolphin appeared healthy and lively but disappeared after a day.

Also, some divers came across an active and curious long-beaked common dolphin near Dangan Islands, south to Hong Kong in August 2006. The divers have taken some shots and video clips of the dolphin.

Spinner dolphin (Stenella longirostris)

General Information:

The spinner dolphin is named after its habit of leaping high above the surface of the water and spinning on its longitudinal axis. The Spinner is slender and small, growing to a length of around 2 meters. Its body has three obvious colours: a dark dorsal cape, lighter grey sides and flanks, and a pinkish white belly. They are gregarious animals and are found in groups of between 50 to a few hundred.

Hong Kong records:

Striped dolphin (Stenella coeruleoalba)

General Information:

Growing to around 2.6m long, the striped dolphin's most distinctive feature is the black stripes on either side of the body that begin as a single stripe from the beak to the eye which then splits into two stripes with one reaching the flipper and the other along the side to the anal region. They are found most frequently close to shore in all tropical and warm temperate waters around the world. Striped dolphins are gregarious and are found in groups of between 10 to a few hundred.

Hong Kong records:

Five Striped dolphin carcasses have been found in Hong Kong with the first one at Pui O, Lantau in 1988. The carcass was fresh when recovered and so the Agriculture and Fisheries Department could later make it into a specimen. Today the preserved animal can be found at the visitor centre at Sai Kung Country Park in Pak Tam Chung. The most recent recorded striped dolphin stranding was a carcass found at Shek O in 1996. No sightings of this species have been reported in Hong Kong .

A striped dolphin found stranded on Tai Long Wan, Hong Kong Island in 1994. Its "eyelines" are clearly visible

Pantropical spotted dolphin ( Stenella attenuata )

General Information:

The most noticeable feature about the Pantropical spotted dolphin is the dense spotting all over its body. Young calves have dark backs and lighter-colour bellies. As they age, more and more spots appear although the degree of spotting varies greatly between regional populations. These dolphins are found in all tropical to warm temperate oceanic waters. Large numbers of Pantropical spotted dolphins have been killed accidentally during the early period of tuna purse seining in the eastern tropical Pacific and as a result, they have been studied extensively and are one of the best-understood oceanic dolphins.

Hong Kong records:

A carcass of a Pantropical spotted dolphin was found near Middle Island in southern Hong Kong Island in 1996. Then in 2000, another carcass was reported near Starling Inlet, Mirs Bay .

Fraser's dolphin (Lagenodelphis hosei)

General information:

Our understanding about Fraser's dolphins is very limited. There had been no recorded sightings or strandings of these dolphins until 1971. Fraser's Dolphin has a robust body (about 2.6m long) and a short beak. The most conspicuous feature in adults is a broad dark stripe from the face to the anus. An oceanic species preferring deeper waters, these dolphins gather in groups of between 100 to 1,000, and are known to swim with other species (such as the Spinner Dolphin, Risso's dolphin, Melon-headed whale and the false killer whale). When moving near the surface, Fraser's Dolphins often create big splashes making them easy to be spotted from a distance. But they rarely let boats near them and so researchers often find them hard to follow.

Hong Kong record:

The only record of Fraser's dolphin in Hong Kong was a carcass found stranded at Plover Cove in Tolo Channel in May 1995.

Risso's Dolphin (Grampus griseus)

General Information:

The specific name, “ griseus ” meaning “grizzled, mottled with grey”, refers to the Risso's body colour. Young calves are grey then as they age, the numbers of scarrings on their bodies increase making their colourings whiter. They are relatively big in size reaching 3.85 m in length when fully grown and have round, beakless heads. Risso's dolphins are widely distributed in tropical and warm temperate waters of all oceans and large seas. They stay mainly in depths of between 200 and 1,000 meters near the steep upper continental slope.

Hong Kong records:

Risso's dolphins have been found stranded in Hong Kong a few times. In June 1986, three or four individuals were washed ashore in several consecutive days near Tai Po in Tolo Harbour . One of the stranded animals was still alive and was rescued and later released. The most recent Risso's dolphin recorded in Hong Kong was a carcass found at Yi Pat Wan of Discovery Bay, Lantau in January 2005.

Rough-toothed dolphin (Steno bredanensis)

The rough-toothed dolphin, Siu Tik, stranded at Lo Tik Wan, Lamma Island in May 2004

General Information:

The Rough-toothed Dolphin is readily distinguished from other long-beaked oceanic dolphins by the shape of its head. It lacks a crease at the base of the melon and the “forehead” slopes smoothly from the blowhole onto the long narrow beak making their heads cone-shaped. The species' common name, “Rough-toothed”, refer to the rough texture of the teeth caused by many fine longitudinal grooves. They are an oceanic species and grow to about 2.5 meters. Restricted to deep tropical and warm temperate waters worldwide, Rough-toothed dolphins are gregarious and stay in pods of around 10-20 members.

Hong Kong records:

The first record of Rough-toothed dolphins was a carcass found floating in the waters near Ching Chau in May 2003. The second case was a live juvenile trapped in Lo Tik Wan on Lamma Island on May 14, 2004 . The dolphin was later taken to Ocean Park and named “Siu Tik” after Lo Tik Wan where it was found. Sadly, Siu Tik died in March
the following year.

For more information about this live stranding incident, please click here

False killer whale (Pseudorca crassidens)

General Information:

The False killer whale is a relatively large dolphin species with adults reaching 5 to 6 meters in length. Their heads are small and rounded with no beaks. They are also known “black fish” because of their charcoal grey body colour. False killer whales look nothing like orcas, or killer whales, but both species have large, drill-like teeth which they use to attack larger animals. False killer whales are found in all tropical and warm temperate waters in schools of between 10 to 50. They have solid social structures, share their preys and are frequently found stranded together.

The juvenile false killer whale stranded on Sai Wan, Sai Kung in August, 2002

Hong Kong records:

False killer whale strandings have been reported four times in Hong Kong . Two carcasses were found in 1983 and 2000 in Tai Lam Chung and Tsin Yue Wan, Lantau respectively. On August 19, 2002, a live juvenile was found stranded on Sai Wan in Sai Kung but died the following day (For more information about this live stranding incident, please click here ). The most recent case happened in 2005 when a dolphin carcass was reported on Town Island , Sai Kung, by a member of the public, who had taken a photograph of the carcass. But the carcass could not be recovered by the AFCD and was later confirmed to be a false killer whale from the photo taken.

Other records of the species include schools of false killer whales spotted in Victoria Harbor (date unknown) and around the Tsing Yi waters (1996).

Pygmy sperm whale / Dwarf sperm whale ( Kogia breviceps / Kogia sima )

Dwarf sperm whale (Photo taken in Taiwan)

General Information:

The pygmy sperm whale (Kogia breviceps) and dwarf sperm whale (Kogia sima) are robust with a dark grey back and lighter-coloured belly. These two species have a somewhat square-shaped head with no beak and a small mouth. They resemble sharks because they have these “false gills” – light-coloured bracket-shaped markings extending from the eyes to the flukes and look similar to fish's gill covers – on the sides of their heads.

Pygmy sperm whales look very similar to dwarf sperm whales although they are larger in size, growing to about 3.5 m in length, whilst the dwarf sperm whales can reach only up to 2.7 m. Also, the dwarf sperm whale has a more prominent dorsal fin in the midpoint of the back.

Both pygmy and dwarf sperm whales are extremely afraid of ships and so observing them is difficult and little is known about them. Both species like to raft motionless at the surface of the sea and dive as soon as they are disturbed. What we do know come from data collected from beached carcasses. These two species have a pan-tropical range, staying offshore and in deep waters.

The pygmy sperm whale stranded in 1992

Hong Kong records :

Five pygmy sperm whale carcasses have been reported between 1986-2003 but detailed examination of the information available from these events, including skull morphology, can only confirm three of them (those occurring in 1986, 1992 and 2003). One was actually a dwarf sperm whale (reported in 1991) while the remaining specimen stays unconfirmed.

Sperm whale (Physeter macrocephalus)

The sperm whale found beached on Tai Wan, Sai Kung in July, 2003

General Information:

The sperm whale is the largest of the toothed whales. Males can grow up to 18 meters long and females about 11 m. Sperm whales are evenly dark grey all over, and have disproportionately large heads. The blowhole is set forward on the head and skewed strongly to the left. They inhabit waters worldwide from the equator to the edges of the polar pack ice.

The sperm whale is an animal of extremes. It dives deeper, and longer, than any other whale. Researchers have found that they can dive to depths between 1,000 to 2,000 meters for up to two hours. They prefer to forage on or near the ocean bottom and rarely venture close to shore. Stable, long-term groups of females form the core units of sperm whale society. Males begin to leave the family groups at about six-years-old to join “bachelor schools”, and become essentially solitary during their breeding prime and in old age.

In the past few decades, sperm whale numbers have declined because of extensive hunting for their body oil, spermaceti and for ambergris, hence their decline in numbers. Today, they are rarely hunted and there is reason for hope that their numbers will recover.

Visitors and researchers were endeavouring to push the stranded sperm whale back to sea

Hong Kong record :

On July 21, 2003 , a live young male sperm whale was discovered stranded at Tai Wan in Sai Kung. Rescue efforts by both visitors and experts proved futile and a vet from the AFCD had to put him down. The carcass was taken to a site near High Island Reservoir west and buried.

For more information of this live stranding incident, please click here

Bryde's whale (Balaenoptera edeni)

The Bryde's whale stranded at Taipa, Macau in 2000. The three longitudinal ridges on the whale's head are clearly visible.

General Information:

Bryde's whale is the only species of baleen whales with a confirmed record in Hong Kong . When fully grown, they could reach lengths of up to 15 m. Most have dark grey backs, with white and sometimes pinkish bellies. Three longitudinal ridges on top of the rostrum are diagnostic of the species. There may be two different types of Bryde's whales: one that lives offshore, the other inshore. Bryde's whales are found worldwide in tropical to temperate waters. Very little is known about the species' abundance, social organization and reproduction.

Hong Kong Records:

The Bryde's whale skeleton is now displayed at the exhibition hall at the Seac Pai Van Park in Coloane, Macau

In 1994, a Bryde's whale carcass was found caught in the net put in place to halt smuggling in Tolo Harbour . Days before that, someone had reported sighting of several Bryde's whales in those waters. Also, there have been five confirmed or probable strandings of this species in Hong Kong during 2003-05. However, among these only one stranded in February 2005 can be confirmed to be a Bryde's whale, while the others were too decomposed to be identified.

Other than these, in August 2000, a live 12-m Bryde's whale was found beached at Taipa in Macau but had died before AFCD personnel and other experts had arrived. The skeleton of this Bryde's whale was later preserved and is now displayed in the exhibition hall at the Seac Pai Van Park in Coloane, Macau.

Common Minke Whale (Balaenoptera acutorostrata)

General information :

With adult body length of only around 9 – 11 m, the Minke is almost the smallest of all baleen whales. Now scientists generally consider there to be two subspecies of Minke whales in the world: the “common” Minke whale and the North Atlantic Minke. Those reported to have occurred in Hong Kong are “common” Minke. They are usually black or dark grey in colour and a white band across the flippers is diagnostic of this species.

Common minke whale - the white band across its flipper is clearly visible (photo taken in Canada)

Although Minke whales are small they are still the primary target for whalers. In the last century, over 100 thousand Minkes have been killed. And nowadays they are still hunted by Norway and Japan . They are widely believed to be abundant in numbers in most areas but there is no solid evidence to support this, hence concerns have been raised on whether their continued exploitation could lead to their extinction.

Hong Kong records :

Several reports of strandings and sightings of Minke whales have been reported in Hong Kong . However, most of these are older records from the 1970s and 1980s with none supported by photos or descriptions of diagnostic characters. And since Minke whales are very similar in size and appearance to the dwarf form of the Bryde's whale, which are regularly found in Hong Kong , most, if not all of these records may be misidentifications of Bryde's whales.

The minke whale may have been found in Hong Kong but evidence available currently suggests otherwise.

Fin whale (Balaenoptera physalus)

General information :

With adult body length up to around 27m, the fin whale is the second largest animal on the planet after the blue whale. The fin whale's body is dark grey above and white or cream-colored below. The fin whale's jaw is black on the left side and white on the right side. Asymmetrical pigmentation of the fin whale's lower jaw is unique.

A pod of fin whales (photos taken at east coast of Canada)

Fin whales are very widely distributed around the globe from the Arctic Ocean to the Antarctica but are less common in the tropics. The Fin whale is a fast swimmer and can reach speeds of up to 25 knots. In the last century, fin whales were very much hunted by whalers. About 725,000 individuals have been killed in the southern hemisphere. Today, scientists are still uncertain about their global status.

The whale skeleton displayed outside the Swire Institute of Marine Science at Cape d'Aguilar

Hong Kong records :

The only record of a fin whale in Hong Kong is a "stranding" in Victoria Harbour on 12 April 1955 when one was trapped between the pillars of a wharf and was subsequently shot. The species of this animal could not be confirmed from the photo taken.

This specimen was later mounted and placed on display at the University of Hong Kong . Then in the early 1990s, it was remounted and moved to an outdoor display at the University's Swire Institute of Marine Science at Cape d'Aguilar, where it remains to this day. It is believed that this specimen may actually have been a misidentified Bryde's whale, and scientists plan to examine it in detail to confirm its species in future.