The second dorsal and anal fins can be very long in mature specimens, reaching almost as far back as the tail and giving the appearance of sickles or scimitars.

The all-tackle International Game Fish Association (IGFA) record for this species stands at 193.68 kg (427.0 lb) for a yellowfin caught in 2012 off Cabo San Lucas, Mexico.

[8][7] Although mainly found in deep offshore waters, yellowfin tuna may approach shore when suitable conditions exist.

Like all tunas, their body shape is particularly adapted for speed, enabling them to pursue and capture fast-moving baitfish such as flying fish, sauries and mackerel.

In turn, yellowfin are preyed upon when young by other pelagic hunters, including larger tuna, seabirds and predatory fishes such as wahoo, shark and billfish.

[7][8] Modern commercial fisheries catch yellowfin tuna with encircling nets (purse seines), and by industrial longlines.

This fishery, which targeted skipjack and occasionally albacore, as well as yellowfin, for canning, reached its heyday between World War I and the 1950s before declining.

The most well-known fleet of pole-and-line boats sailed from San Diego[14] in California and exploited abundant stocks in Mexican waters, as well as further south to Panama, Costa Rica and the Galapagos Islands.

The latter practice in particular has a major ecological impact because of the high proportion of bycatch, including manta rays, sea turtles, pelagic sharks, billfish and other threatened marine species taken by setting nets around logs and other floating objects.

Industrial longlining was primarily perfected by Japanese fishermen who expanded into new grounds in the Western Pacific, Indian and Atlantic Oceans in the late 1950s and early 1960s.

Tuna longlining targets larger sashimi-grade fish around 25 kg (55 lb) and up that swim deeper in the water column.

In tropical and warm temperate areas, the more valuable bigeyes are often the main target, but significant effort is also directed towards larger yellowfins.

Bycatch is a major environmental issue in the longline fishery, especially impacting billfish, sea turtles, pelagic sharks and seabirds.

[citation needed] Artisanal fishermen tend to employ assorted hook-and-line gear such as trolling lines, surface and deep handlines and longlines.

Yellowfin tuna were subsequently discovered by sport fishermen in Bermuda, the Bahamas, Hawaii and many other parts of their range.

Larger adult fish which had developed distinctively long sickle fins were initially thought to be a different species and were known as Allison tuna (a name first given by the then curator of the Bermuda Aquarium, Louis Mowbray, in 1920).

Thousands of anglers fish for yellowfin tuna along the eastern seaboard of the United States, particularly in North Carolina and New England.

The yellowfin tuna is also a highly prized catch in the offshore sport fisheries of South Africa, Australia and New Zealand.

Recreational fishing for yellowfin tuna in the Gulf of Mexico is a significant contributor to the region's economy, with an estimated economic impact of $7 billion annually.

Yellowfin tuna are highly sought after for their impressive size and excellent taste, making them a popular target for recreational anglers.

The thrill of reeling in a massive yellowfin tuna has attracted many fishing enthusiasts to the Gulf of Mexico, creating a significant source of revenue for local businesses and communities.