ON THE GEOGRAPHICAL DISTRIBUTION AND FAUNAL CHARACTERISTICS OF THE CHONDRICHTHIAN FISHES OF CHINA

The Chondrichthian fishes of China, as known at present, are represented by 127 species, 60 genera and 28 families, here grouped under 14 groups as follows: (1) The Hexanchoids are represented by 1 family (Hexanchidae), 3 genera and 3 species; (2) The Heterodontoids by 1 family (Heterodontidae), 1 genus and 2 species; (3) The Lamnoids by 6 families (Carchariidae, Lamnidae, Cetorhinidae, Alopiidae, Orectolobidae and Rhin-codontidae), 11 genera and 18 species; (4) The Scyliorhinoids by 4 families (Scyliorhini-dae, Triakidae, Carcharhinidae and Sphyrnidae), 19 genera and 43 species; (5) The Squaloids by 1 family (Squalidae), 2 genera and 4 species; (6) The Pristiophoroids by 1 family (Pristiophoridae), 1 genus and 1 species; (7) The Squatinoids by 1 family (Squa-tinidae), 1 genus and 2 species; (8) The Pristoids by 1 family (Pristidae), 1 genus and 2 species; (9) The Rhinobatoids by 2 families (Rhinobatidae and Platyrhinidae), 4 genera and 9 species; (10) The Torpedinoids by 2 families (Torpedinidae and Nat-kidae), 3 genera and 5 species; (11) The Rajoids by 1 family (Rajidae), 1 genus and 7 species; (12) The Dasyatoids by 2 families (Dasyatidae and Gymnuridae), 5 genera and 17 species; (13) The Myliobatoids by 4 families (Myliobatidae, Aetobatidae, Rhin-opteridae and Mobulidae), 6 genera and 12 species; (14) The Chimaeroids by 1 family (Chimaeridae), 2 genera and 2 species.The faunal composition of Chinese Chondtichthian fishes is characterized by the fact that the members of the Carcharhinidae, Dasyatidae and Myliobatidae are especially abundant, and next in importance ate the Orectolobidae, Scyliorhinidae, Alopiidae and Sphyrnidae, etc., but the representation of the Squalidae, Rajidae and Chimaeridae is noticed to be rather weak.According to the adaptive thermal nature of the species, the Chondrichthian fishes of China may be referred to three types, viz., the warm-water, the warm-temperate and the cold-temperate. The warm-water species are 74 in number, occupying 59 % of the total; the warm-temperate species 39 in number occupying 30%; the cold-temperate species 14 in number, occupying 11%.In the South China Sea area, there are 107 species, of which the warm-water species constitute 69%, the warm-temperate species 28 %, and the cold-temperate species about 3%. Of the East China Sea area, the number of species is represented by 74, among which the warm-water species constitute 43%, the warm-temperate species 39%, and the cold-temperate species 18%. The Yellow Sea and Po Hai areas possess 45 species, the ratio of the warm-water species being 27%, that of the warm-temperate species 42%, and that of the cold-temperate species 31%.Of the above-mentioned 127 species of the Chondrichthian fishes represented in the Chinese waters, 28 species are common along the whole coast, 27 species are common in the South China Sea and the East China Sea, 16 species are common in the East China Sea and the Yellow Sea and Po Hai; 52 species are confined to the South China Sea, 3 species to the East China Sea, and only a single species to the Yellow Sea and Po Hai. As some Chondrichthian fishes obviously exhibit the phenomenon of migration, so the faunal composition of each area varies to some extent in different seasons.The fauna of Chinese Chondrichthian fishes is found to be closely related to that of Japan, Korea and the Philippines. There are 70 species distributed in common to both China and Japan, among which 7 are peculiar to these two countries; 51 species common to both China and Korea; 52 species common to both China and the Philippines, of which 2 are peculiar to these two countries. There are 17 endemic species in China, 34 in Japan, 10 in the Philippines, and none in Korea. However, there is a certain number of cold-water and deep-sea species of Japan, a few cold-water species of eastern Korea, and some warm-water and deep-sea species of the Philippines, which are all not represented in our fauna.