NATURAL HISTORY

TAIWANESE HUMPBACK DOLPHIN } Sousa chinensis taiwanensis
FAMILY: Delphinidae

DESCRIPTION: The Taiwanese humpback dolphin is a critically endangered marine mammal — with fewer than 80 individuals — that lives along the densely populated west coast of Taiwan. One of two known subspecies of the Indo-Pacific humpback dolphin, the Taiwanese humpback is a small-to-medium-sized cetacean ranging in color from grayish-pink to dark gray, often with mottled spotting near the wide base of its dorsal fins.

HABITAT: The Taiwanese humpback lives in the estuaries and other nearshore coastal environments off the western coast of Taiwan.

RANGE: This dolphin ranges from the northern Houlong and Jhonggang rivers (Miaoli County) to the southern Waishanding Zhou sandbar (Chaiyi County).
Its coastal range is very limited; sightings outside this range have rarely occurred.

MIGRATION: The Taiwanese humpback dolphin occupies a small geographic area along the western coast of Taiwan and has no known routes of migration.

BREEDING: While little is known about this specific population of dolphin's mating habitats, Indo-Pacific humpback dolphins breed yearly, with births typically occurring in the spring or summer following a 10–12 month gestation period. 

LIFE CYCLE: Taiwanese humpback dolphins can live 40 years or more in the wild. Indo-Pacific humpback dolphins are rarely raised in captivity, and those that have been typically die within a few months.

FEEDING: Little information exists about feeding habits of the Taiwanese humpback dolphin. Observers have seen these animals feeding on herring, mullets, croakers and threadfins, suggesting that the subspecies mostly forages in shallower waters, such as estuaries and other nearshore coastal environments. These feeding patterns are consistent with those observed in other Indo-Pacific humpback dolphins, which typically feed on estuarine and reef fish.

THREATS: Bycatch, entanglement, habitat destruction and degradation, noise, pollution of coastal and river waters, and boat traffic are among the most important and pervasive threats to this subspecies in the Taiwan Strait. The main threat to the survival of Taiwanese humpback dolphins is from fishing, via bycatch and entanglement in fishing gear such as trammel nets, gillnets and trawls.

POPULATION TREND: Population estimates of the Taiwanese humpback dolphins in 2010 placed the number at around 74 individuals and declining.

Taiwanese humpback dolphin courtesy Hong Kong Dolphin Conservation Society