Field identification of yellowfin and bigeye tuna

Abstract

Tunas are commercially important food fishes exploited from all the world oceans. Of the 9 species contributing to the Indian tuna fisheries, yellowfin and bigeye tuna grow to big sizes, and with superior meat quality have high export demand. Identification of these tuna species are comparatively easier in fresh condition than the iced or frozen condition due to discolouration, fin and skin damage during handling and storage process. In such cases certain internal characteristics such as length of air bladder, liver shape and striation are used. Misidentification of yellowfin and bigeye tunas occurs in several cases. The present study is based on field observations at Cochin Fisheries Harbour and uses an easy field identification key for yellowfin and bigeye tuna based on external characteristics developed by Itano (2005) and IOTC (2013). Bigeye tuna are landed stray numbers along with yellowfin tunas, at Cochin Fisheries Harbour.