Chumming & Chunking
As with most of the tunas, chumming or chunking can work well as an attractor. This can be done with ground chum, chunked fish or live bait. Once the fish are working in the chum, then a variety of methods will catch them Sirface casting with spinning, plug or fly tackle provide exciting action. Using dead bait will also work.
By far, those who work these fish from a boat have the advantage. The boat needn't be large, but it should be big enough to meet the fish on their own ground.
After locating a surface school of Blackfin Tuna, try to position the boat well ahead of the school and shut off the motors. Remember, you are actually seeing the upper 10% of the school. Its bigger than you think. Then begin casting to the school as it passes. At times, several schools will be in the area, so look for further action. Such techniques work equally well for conventional, spinning, and fly casting.
When Blackfin Tuna are thick and plentiful, or if you are just "feeling" them out, then trolling will take these fish. Present long flat-lines and position the lures so they contact the head of the school-- the lead fish. Then again, sometimes Blackfin Tuna are moving so fast that trolling is impossible.