Neophocaena phocaenoidesfinless porpoise

Ge­o­graphic Range

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)

Habi­tat

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

Phys­i­cal De­scrip­tion

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
    66.08 to 99.12 lb

Re­pro­duc­tion

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
  • Average number of offspring
    1
    AnAge
  • 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

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

Lifes­pan/Longevity

Be­hav­ior

Neopho­caena pho­caenoides is a rel­a­tively slow an­i­mal. It rolls to the sur­face to breath and is rarely ob­served jump­ing out of the water. Max­i­mum dives last up to 11-15 sec­onds. It forms mostly small schools and is rarely seen in groups of more than 4. More often, N. pho­caenoides is soli­tary or in mother-off­spring groups. Some of the groups of N. pho­caenoides (mainly the Japan­ese groups) are mi­gra­tory. They fre­quent the In­land Sea dur­ing the spring and mi­grate to the Pa­cific coast from late sum­mer to mid­win­ter. (Gaskin 1982, Ganslosser 1988, Nowak 1991)

Com­mu­ni­ca­tion and Per­cep­tion

Food Habits

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

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Neopho­caena pho­caenoides is hunted by hu­mans for its meat, skin and oil (Nowak 1991).

Con­ser­va­tion Sta­tus

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)

Other Com­ments

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).

Con­trib­u­tors

Lin­dasy Du­Vall (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

piscivore

an animal that mainly eats fish

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

solitary

lives alone

tactile

uses touch to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

Ref­er­ences

Bry­den, M. and Har­ri­son, R. 1986. Re­search on Dol­phins. Claren­don Press, Ox­ford.

Ganslosser, U. 1988. Griz­imek's En­cy­clo­pe­dia. Mc­Graw-Hill Pub­lish­ing, New York. Vol 4. pgs. 386, 414-415.

Gaskin, D.E. 1982. The Ecol­ogy of Whales and Dol­phins. Heine­mann, Lon­don. pgs. 3, 127, 229, 235.

Her­man, L. 1980. Cetacean Be­hav­ior. John Wiley and Sons, New York. pg 268.

Nowak, R.M. 1991. Walker's Mam­mals of the World. Johns Hop­kin's Uni­ver­sity Press, Bal­ti­more. Vol 2. pgs. 1005-1006.