GEOGRAPHICAL VARIATION OF EXTERNAL MEASUREMENTS AND THREE SUBSPECIES OF NEOPHOCAENA PHOCAENOIDES IN CHINESE WATERS

Abstract

The finless porpoise,Neophocaena phocaenoides,is distributed in the form of a nar-row band along the coast line of tropical and temperate Asia and in the Yangtze river.The differences of external measurements among the populations in Chinese waterswere studied using t-test,analysis of covariance and discriminant analysis. Based on 226specimens collected between 1974 and 1993 by the Cetacean Research Laboratory,Nan-jing Normal University.A total of 84 from Yangtze population, 97 from Yellow Seapopulation and 45 from South China Sea population was available for study. According to the distinct differences in external measurements,skull measurements(Gao,1991),growth and reproduction pattern(Gao et al,1993)among the YangtzeRiver, Yellow Sea and South China Sea populations as well as the differences among theChinese populations and the South Asian and Japanese populations,the authors suggestthat Neophocaena phocaenoides be consisted of 3 subspecies:1)Neophocaena pho-caenoides phocaenoides(Cuvier,1829 ),inhabits the coastal waters of South China Seaand southern part of East China Sea. Diagnosis:Dorsal ridge originates after the mi-dlength on dorsum,10-14 rows of tubercles,tubercle area is 48-120 mm or larger inwidth.2)N. P. sunameri Pilleri and Gihr,1975,inhabits the coastal waters of YellowSea,Bohai Sea,East China Sea and off the west coast of Korea,Diagnosis:Dorsal ridgeoriginates before or at midlength on dorsum,16 mm or more in height,and reaches 55mm in maximum,2-9rows of tubercles,may exceed 9 rows in Japanese porpoise,Tu-bercle area 12 mm or less in width,may exceed 12 mm a bit in Japanese porpoise.3)N.P. asiaeorientalis(Pilleri and Gihr,1972),inhabits the middle and lower reaches of theYangtze River,the Dongting Lake and the Boyang Lake. Diagnosis:Dorsal ridge origi-nates before or at midlength on dorsum,2-5rows of tubercles, tubercle area 8 mm orless in width.Dorsal ridge hardly exceeds 15 mm in height.This is the only subspeciesinhabiting freshwater. Statistical analysis also demonstrates that:among the three pop-ulations in the Chinese waters, individuals from the Yellow Sea population have thelongest snout,while those from the South China Sea have the shortest;Individuals fromthe Yangtze population have the thickest blubber,while those from the South China Seahave the thinnest; The girth of the individuals from the Yangtze population is relativelylarger than that from the other two populations.The barrier between N. P. pho-caenoides and N. P.sunameri may be attributed mainly to the water temperature in dif-ferent areas.That between N. P. asiaeorientalis and the coastal population may bemainly attributed to the salinity of the river and sea waters.