Difference between juvinile yellowfin and blackfin tuna

[southernstyle995]

Got into a bunch of blackfin yesterday and caught a couple decent yellowfins but had one or two small 9nes that I couldn't tell if it was a young yellowfin or if it was a blackfin. What are the main identifiers between a juvinile yellowfin and a blackfin

 

[SkunkBoat]

YFT have yellow finlets on tail and they have white spots & stripes on belly
YFT Second dorsal fins are longer and have yellow in them even when young
YFT Second dorsal fin is taller than 1st and always longer than blackfin's


Tuna Guide

 

[Doc Stressor]

The finlets between the second dorsal fin and the tail are almost always yellow on yellowfin tuna and brownish on blackfins.

If there are stripes on the juveniles you caught, they are vertical on blackfins and horizontal on yellowfins.

Yellowfins have over 25 gill rakers and blackin have less than 25. But those are hard to count on live fish.

 

[southernstyle995]

Thanks guys!!