Pole & Line vs. Net-Caught Tuna: Why the Fishing Method Changes Everything

Two Very Different Ways to Fill a Tuna Can

Most people never think about how the tuna in their pantry got there. American Tuna was founded by six Pole & Line fishing families in San Diego in 2004 — and the fishing method is the foundation of everything the brand stands for. Pole & Line tuna vs. net-caught tuna is not a branding distinction. It is a real difference in how fish are harvested, what else gets caught in the process, and what shows up in the can when the fishing is done.

The global canned tuna market is dominated by two industrial methods: purse seine net fishing and longline fishing. Both are efficient at catching large volumes of fish. Both have well-documented problems with bycatch, fish quality, and supply chain opacity. Understanding what separates Pole & Line fishing from those methods is the most direct way to understand why fishing method matters on your grocery shelf.

How Purse Seine Net Fishing Works

Purse seine fishing is the dominant method for catching skipjack and yellowfin tuna at commercial scale. A large vessel deploys a circular net — sometimes a mile or more in circumference — around a school of fish and then draws the bottom of the net closed like a purse, trapping everything inside. The catch goes aboard for processing. A single purse seine set can haul hundreds of tons of fish in a single operation.

The efficiency of purse seine fishing is its advantage and its problem. Schools of tuna often travel with other species — dolphins, sea turtles, mahi-mahi, sharks. Early purse seine operations had catastrophic dolphin bycatch rates, which led to the "dolphin-safe" labeling movement starting in the late 1980s. Modern purse seine operations have reduced but not eliminated bycatch. The method remains the most cost-efficient way to move high volumes of tuna, which is why it dominates the StarKist, Bumble Bee, and Chicken of the Sea supply chains.

How Longline Fishing Works — And Its Own Set of Problems

Longline fishing deploys lines stretching 50 to 100 miles through the ocean, with thousands of baited hooks attached at intervals. Vessels haul the lines back after hours or days, bringing up whatever has taken a hook. Longline is the primary method for targeting albacore and bigeye tuna at commercial scale, and it produces large, marketable fish because the lines can be set at depths and locations that concentrate bigger specimens.

Bycatch is a persistent problem for longline operations. Sea turtles, seabirds (especially albatross), sharks, and non-target fish species all take hooks alongside the target tuna. Longline bycatch rates vary significantly by fishery management and gear configuration, but the method is structurally less selective than Pole & Line because the hooks are unattended in the water and cannot discriminate between target and non-target species. The other issue with longline: larger, older fish targeted for commercial yield carry more accumulated mercury.

Pole & Line: What One Fish at a Time Actually Means

Pole & Line fishing works exactly as it sounds. A fisherman stands at the rail of the boat holding a bamboo or fiberglass pole attached to a short, strong line with a barbless hook. When a tuna takes the hook, the fisherman swings the fish aboard in a single motion. The barbless hook releases on contact with the deck, and the fisherman returns the line to the water. Experienced Pole & Line crews can land one fish every few seconds during an active school.

The selective advantage is significant. The fisherman can see the fish before it is caught and can choose not to swing if the hook has caught something unintended. Bycatch in Pole & Line fisheries is a fraction of what it is in purse seine and longline operations — typically under one percent by weight. American Tuna's catch is exclusively Pole & Line on US-flagged vessels operated by American fishing families in the Pacific. Shop American Tuna and see the sourcing transparency on the label.

What Fishing Method Does to Fish Quality

The handling difference between Pole & Line and net fishing produces a real quality difference in the final product. A Pole & Line caught albacore comes aboard individually, is handled by a fisherman, and is chilled immediately. There is no mass compression in a net, no extended time surrounded by other fish in various states of stress, and no delay between catch and processing. The fish arrives at the processing facility in better condition — which translates to firmer texture, cleaner flavor, and better oil content in the finished can.

Net-caught fish — particularly from purse seine operations — undergo compression, heat build-up from mass contact, and often a longer time between capture and processing. These conditions degrade muscle texture and accelerate oxidation. The commodity canned tuna that emerges from that process can be perfectly safe and adequately nutritious. But it is a different product from a single-handled, immediately chilled Pole & Line albacore. The difference is visible and tasteable side by side.

Mercury Levels: Does the Fishing Method Matter?

It does — indirectly. The fishing method itself does not add or remove mercury from a fish. What it influences is the age and size of the fish being caught. Longline fisheries targeting commercial albacore pursue the largest, most marketable fish available — older specimens that have had more years accumulating methylmercury through the food chain. Pole & Line fishing catches fish of whatever size is present in an active school, including younger, smaller albacore that carry less accumulated mercury.

This is why American Tuna's Pole & Line catch tends to run lower in mercury on average than commercially targeted large albacore. The 0.35 ppm FDA average for albacore is based on the commercial catch, which skews toward bigger fish. Well-sourced Pole & Line albacore from a younger catch profile can run meaningfully lower than that average. Visit americantuna.com for more detail on sourcing and processing transparency.

What to Look For on a Tuna Label

When buying canned tuna and evaluating fishing method claims, a few label indicators are worth checking. "Pole & Line caught" or "Pole and Line" is the most specific claim and the most verifiable — it is a method that cannot be faked at scale because it requires individual fish handling. "Troll caught" is the next most selective method — lures dragged behind a moving vessel, producing selective catches with lower bycatch than net methods. "Dolphin-safe" refers only to dolphin bycatch and does not indicate fishing method. "MSC certified" confirms a third-party sustainability audit of the fishery but does not guarantee Pole & Line.

American Tuna is Pole & Line caught, MSC certified, domestically processed, and vessel-traceable — all four of the most meaningful sustainability and quality indicators in the canned tuna category. Most commodity brands can claim none of these. Most premium competitors can claim two or three. The combination of all four in a single brand is uncommon.

Frequently Asked Questions About Fishing Methods

Is Pole & Line tuna always more sustainable than net-caught?

In terms of bycatch rate and selectivity, yes. Pole & Line is the most selective commercial tuna fishing method available, with bycatch rates well under one percent by weight in well-managed fisheries. Purse seine and longline methods have higher structural bycatch rates, though modern gear modifications have reduced the gap in some certified fisheries.

Does troll-caught tuna compare to Pole & Line?

Troll fishing is also considered a low-bycatch, selective method — significantly better than purse seine or longline. The difference is that troll fishing uses multiple lures or hooks at once dragged behind a moving boat, while Pole & Line is fully individual-fish handling. Both are legitimate sustainable choices, with Pole & Line being the more specific and accountable of the two.

Why don't more brands use Pole & Line fishing?

Cost and scale. Pole & Line fishing produces lower yields per vessel per trip than net fishing and requires skilled, experienced crews. The economics do not work for brands competing primarily on price. American Tuna can sustain it because the brand was founded by fishing families who operate the vessels themselves, eliminating the labor cost layers that make Pole & Line unworkable for commodity brands.

How do I know if a tuna brand is actually Pole & Line caught?

The fishing method should be stated explicitly on the can or the brand's website with verifiable sourcing information — not hidden in marketing copy. American Tuna states it on every can and provides vessel-level traceability. If a brand claims Pole & Line but cannot name the vessels or fishery, that claim is worth scrutinizing.