A systematic review of the scombroid fishes of India

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A SYSTEMATIC REVIEW OF THE SCOMBROID FISHES OF INDIA

S. JONES AND E. G. SILAS

Central Marine Fisheries Research Institute, Mandapam Camp

From the standpoint of marine fishery resources there can be no doubt that scombroid fishes constitute the most important single element. Large scale exploitation of a

*greater part of this natural resource, especially of the truly pelagic species comprising tunas and billfishes has been in vogue for the past several decades, mainly by Japan and the United States of America. The importance of this potential wealth in the Indian Ocean has be& forcefully d&in attention to by the extensive fishing operations carried out by the Japanese longline fishery fleets in the high seas of the Indian Ocean, and by exploratory offshore fishirig operations carried out by some countries bordering the Indian Ocean.

Both at the symposium and conference on the biology of tunas and related fishes held recently at Dakar (Nov. 1960), and Honolulu (Aug. 1961) attention was drawn. by workers to the urgent need for knowing more about the species occurring in the different geographical areas to help understand the precise distribution of the species, the occurrence of populations if any, etc. While regional reviews of scombroid fishes have been carried out in the Pacific and Northern Atlantic by several workers, the Indian Ocean has till recently remained a veritable blank. The recent regional works from this area (Munro 1943 ; S e m t y 1941, 1956 ; Deraniyagala 1952 ; Fourmanoir 1957 ; Williams 1959 ; and Jones and Silas, 1960, 1961) ; a review of scombroid fishes of the world by Fraser-Brunner (1950); and the work on Pacific scombroid fishes mainly by Kishinouye (1923); Nakamura (1938, 1949);

Godsil and Byers (1944); Godsil (1954) ; Royce (1957) ; Robins and de Sylva (1960), etc., have helped us in our knowledge about the species of scombroid fishes occurring in the

Indian Ocean. ,

, In this review we have covered the mackerels, tuna and related species, seerfishes, wahoo, and the billfishes occurring in Indian seas. Along with nomenclatorial discussions, meristic and morphometric data for the different species are given wherever possible. The key for the identification of the species has been made comprehensive and includes all specim recognised as. valid from the Indian Ocean. Since our knowledge of the precise distribution of the different species' in the Indian Ocean itsqlf is far from complete, this coupe has been adopted to aid future investigators in their field identification. An outline of tho classification followed is also given and all the species are illustrated.

The discussion includes comparison of scombroids of the Indian Ocean and those occurring in the Pacific and Atlantic.

KEY TO THE IDENTIFICATION OF MACKERELS, TUNAS, S E ~ ~ ~ S H W AND

BILLPISHES FROM INDIAN OCEAN

fa, Upper jaw strongly produced into a rounded ' spear ' or a powerful flat

'

sword';

no finlets' behind'second dorsal and second (soft) anal ; pelvics when present reduced to one, two or three s p i s (Istiophoridae and Xiphiidae)

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