Seasonality, morphometrics and feeding behaviour of yellowfin tuna (Thunnus albacares) caught by sports fishers in the Kenyan waters

Yellowfin tuna (Thunnus albacares) are among the major target species caught by sports fishers in Kenyan waters. The study on the feeding habits of the tuna was conducted between November 2012 and January 2013 which is the peak season for yellowfin tuna in the Kenyan waters. For seasonality data, a 19 year daily catch data from 1987 to 2011 was used. The yellowfin tuna were most abundant in the coastal waters during the months of October and November. There were two distinct size classes caught during this study. The smaller ones had an average weight 7.2 ± 1.0 kgs and had an average fork length of 73.4 ±5.6 cm. The larger ones had an average weight 26.1 ± 4.4 kgs and had an average fork length of 110.8 ±7.0 cm. The major food contents in the fish stomachs were crabs (Charybdis smithii), Sepia spp., anchovies (Stolephorus commersonii) and Kawakawa (Euthynus affinis). The study also compared the feeding habits of tuna and sailfish and found a similarity in stomach content of the larger yellowfin tuna and the sailfish while that of the smaller yellowfin tuna was different from the larger tuna and sailfish.