Notary and apostille services near meYellowfin tuna grow to be massive: the largest recorded yellowfin tuna caught weighed 388 lbs and was over 6 feet long. Since they grow to be especially large, yellowfin tuna enjoy eating a variety of smaller baitfish and squid. They also can swim very fast, which allows them to hunt flying fish, mackerel and sardines.Pandas groupby standard deviationTrolling Patterns The best trolling speed for us is 6-7.5 knots. If your running or scouting for signs, 8-10 knots is a good speed to run until you find signs or fish. Every boat has a different wake depending on their size and prop systems, so choose a pattern that puts your jigs in the "blue holes" that are created at trolling speed.