Although N. phocaenoides is not endangered, there are many threats to its survival as individuals if not as a species. Neophocaena phocaenoides is effected by pollution as well as bottom dredging. It is also killed by motor boat collisions, hunters, fish and shrimp nets, and its natural predator, the shark. (Bryden & Harrison 1986, Nowak 1991)
IUCN Red List of Threatened Species: vulnerable
Neophocaena phocaenoides is sometimes called the Black Finless Porpoise because of the common misconception that its skin is black. In reality, the upper portions of N. phocaenoides are gray with touches of blue on the back and sides. The ventral parts are paler. Pale spots do however decrease with age, and the skin turns black immediately after death. Further, the skin coloring differs from pale in oceanic and brackish waters, to almost black in rivers. Neophocaena phocaenoides has no dorsal fin but has instead has a midline dorsal ridge. This ridge contains horny papillae. Neophocaena phocaenoides is the smallest cetacean and grows to only 150-190cm. It has a distinct eel-like shape due to its lack of dorsal fin and round, beakless head. The jaw of N. phocaenoides contains 15-21 spade shaped teeth on each side of the upper and lower jaw. (Ganslosser 1988, Herman 1980, Nowak 1991)
Range mass: 30 to 45 kg.
Other Physical Features: endothermic ; bilateral symmetry
Average lifespan
Status: wild: 23.0 years.
Neophocaena phocaenoides lives in both fresh and salt water habitats. It is found in shallow coastal waters such as the Sea of Japan as well as fresh water rivers like the Yangtze river in China. Neophocaena phocaenoides is occasionaly found in inland lakes which have been cut off from the ocean but are still salt water. Neophocaena phocaenoides seems to prefer rocky promonotories and strong currents (Ganslosser 1988).
Aquatic Biomes: rivers and streams; coastal
Neophocaena phocaenoides is found in the coastal waters and rivers of Southeast Asia. It is concentrated in the eastern IndoPacific region. Neophocaena phocaenoides can be found from Pakistan to Korea, Japan, Borneo and Java. (Gaskin 1982, Nowak 1991)
Biogeographic Regions: oriental (Native ); indian ocean (Native ); pacific ocean (Native )
Neophocaena phocaenoides feeds mainly in the euphotic zone. It eats benthic invertebrates, cephalopods such as squid, and small demersal fish. Neophocaena phocaenoides is a very aggresive hunter, and fish have been observed jumping out of the water when chased by it (Bryden & Harrison 1986). (Gaskin 1982)
Animal Foods: fish; mollusks; aquatic crustaceans
Primary Diet: carnivore (Piscivore )
Neophocaena phocaenoides is hunted by humans for its meat, skin and oil (Nowak 1991).
Perception Channels: tactile ; chemical
Neophocaena phocaenoides appears to be very adaptable and is found in habitats which other species have abandoned. These include the Tung-Ting Lake in China, which is landlocked and extremely shallow. However, N. phocaenoides isn't as quick to adapt to human ways. They tend to eat objects off the river bottom, including things as detrimental to their health as bottle caps thrown in the water by humans; these appear to be a major cause of death (Bryden & Harrison 1986).
Neophocaena phocaenoides reaches sexual maturity by the age of 2. Reproductive cycles differ among geographic groups such as those located near Japan and those near China. The breeding cycle is 1-2 years and gestation lasts between 10 and 11 months. Births occur between February and August and there is usually 1 young per birth. Newborns are around 25kg and are weaned between September and June. Neophocaena phocaenoides has been found to live up to 23 years. (Bryden & Harrison 1986, Nowak 1991).
Breeding interval: The breeding cycle is 1-2 years
Average number of offspring: 1.
Range gestation period: 10 to 11 months.
Range weaning age: 7 to 10 months.
Range age at sexual or reproductive maturity (female): 2 (high) years.
Range age at sexual or reproductive maturity (male): 2 (high) years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous
Average birth mass: 7000 g.
Average number of offspring: 1.
Mothers carry their offspring on a patch of skin on the dorsal surface which is covered with horny papillae. This acts like a saddle on which the young can attach and be carried. Although obviously for carrying young, the horny papillae contain nerve endings and may be a means of auxillary orientation. This "extra" means of orientation could be very beneficial to N. phocaenoides since it often lives in murky waters.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
The Indo-Pacific finless porpoise (Neophocaena phocaenoides) is one of eight porpoise species. The species ranges throughout most of the Indian Ocean, as well as the tropical and subtropical Pacific from Indonesia north to the Taiwan Strait. Overlapping with this species in the Taiwan Strait and replacing it northwards is the East Asian finless porpoise (N. sunameri).
The Indo-Pacific finless porpoise lives in the coastal waters of Asia, especially around Indonesia, Malaysia, India, and Bangladesh. At the western end, their range includes the length of the western coast of India and continues up into the Persian Gulf. On the eastern edge of their range, they are found throughout the Indonesian archipelago and range north to the Taiwan Strait. Finless porpoises are also one of the species protected at Sundarbans National Park.
Finless porpoises can grow to as much as 2.27 m (7 ft 5 in) in length, and can weigh up to 72 kg (159 lb), although most are rather smaller.[3] The flippers are moderately large, reaching up to 20% of the total body length. Adults are typically a uniform, light grey colour, although some may have lighter patches of skin around the mouth or darker patches in front of the flippers. Newborn calves of the central and eastern subspecies are mostly black with grey around the dorsal ridge area, becoming fully grey after four to six months. However, newborn calves of the western subspecies are a light creamy grey, and become darker as they age.[3]
Adults grow more than 1.55 m (5 ft) in length and up to 30–45 kg (65–100 lb) in weight.
The anatomy of finless porpoises has been relatively well studied, compared with that of some other cetacean species. For example, the tubercles along the dorsal ridge are known to contain numerous nerve endings that may possess a sensory function. The auditory system also appears well-developed, with numerous large nerve fibres specialised for rapid communication between the ears and the brain. On the other hand, sight is relatively poor, with a reduced lens and a limited number of fibres in the optic nerve and to the muscles moving the eyes.[3]
The skeleton is unusually light, accounting for only 5% of the total weight of the animal. There are between 58 and 65 vertebrae, about half of them in the tail, and with the first three cervical vertebrae fused into a single structure. There are ten to fourteen pairs of ribs in the chest, and an additional set of vestigial ribs has sometimes been reported in the neck, in association with the seventh cervical vertebra.[3] There are 44 sets of spinal nerves.[4]
The nasal passage contains nine or ten air sacs, which have a complicated structure, and are capable of sealing off all air within the passage. Behind these are an additional set of vomeronasal sacs.[5] The trachea, however, is short, with only four cartilaginous rings.[3] The stomach has three chambers, there is no caecum, and no distinct difference between the small and large intestines.[6][7]
Finless porpoises are opportunistic feeders using various kinds of available food items available in their habitat, including fish, crustaceans, and cephalopods.[8] They are reported to eat fish, shrimp and squid off Pakistan. Seasonal changes in their diets have not been studied. They also apparently ingest some plant material when living in estuaries, mangroves, and rivers, including leaves, rice, and eggs deposited on vegetation.
Recent data suggest the basic unit of a finless porpoise pod is a mother/calf pair or two adults, and schools of three or more individuals are aggregations of these units or of solitary individuals. Social structure seems to be underdeveloped in the species, and the mother/calf pair is probably the only stable social unit.
Like other porpoises, their behaviour tends to be not as energetic and showy as that of dolphins. They do not ride bow waves, and in some areas appear to be shy of boats.[3]
Finless porpoises make both high frequency clicking sounds, and longer, low frequency tones, the latter perhaps being for communication, rather than echolocation.[9] The clicks are narrow-band, with peaks of over 100 kHz.[10]
A new study from Woods Hole Oceanographic Institution (WHOI) study that was published in The Journal of Experimental Biology, "highlights the differences in dolphins' ability to hear across species, reshaping the previous 'one-size-fits-all' approach taken on the hearing ability of the cetaceans".[11]
Although they show no acrobatics in the water, finless porpoises are believed to be very active swimmers. They typically swim just beneath the surface of the water and roll to one side when surfacing to breathe. This rolling movement disturbs very little water on the surface, so they are often overlooked when rising to breathe. Surfacing generally lasts for one minute, as they take three to four quick successive breaths, then quickly submerge into the water. They often surface a great distance from the point where they dive beneath the water's surface. Dives lasting over four minutes have been recorded, and a common pattern of behaviour is to take one long dive, followed by two shorter ones.[3]
Breeding occurs in late spring and early summer.. The young are born in spring, summer, or winter, depending on the geographic locality, after a gestation period of ten to eleven months. Newborn finless porpoises are reported to 72 to 84 cm (28 to 33 in) in length.[3][12] Males reach sexual maturity at four to six years of age, and females at six to nine years.[12] Finless porpoises have lived up to 33 years.[3]
It has been claimed that young calves cling to the denticulated area of skin on their mother's back and are carried by her as she swims, but there is no clear evidence of this happening.[3] Calves are weaned at 6–15 months.
The finless porpoise is listed on Appendix II[13] of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). It is listed on Appendix II[13] as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.
Since this species remains in coastal waters, it has a high degree of interaction with humans, which often puts the finless porpoise at risk. Like other porpoises, large numbers of this species are killed by entanglement in gill nets. The primary danger to the species is environmental degradation. Unlike other members of this family, finless porpoises have lived in captivity for over 15 years.
There are no well-established estimates of the animals' abundance. However, a comparison of two surveys, one from the late 1970s and the other from 1999–2000, shows a decline in population and distribution. Scientists believe this decline has been ongoing for decades, and the current population is just a fraction of its historical levels. Along the southern coast of Pakistan in the Arabian Sea it is declared as an endangered species.
The WWF Website states that the finless porpoise is Critically endangered.[14] However, it is not the official 'IUCN Endangered Status'.
The Indo-Pacific finless porpoise (Neophocaena phocaenoides) is one of eight porpoise species. The species ranges throughout most of the Indian Ocean, as well as the tropical and subtropical Pacific from Indonesia north to the Taiwan Strait. Overlapping with this species in the Taiwan Strait and replacing it northwards is the East Asian finless porpoise (N. sunameri).
