Yellowfin tuna are caught with a variety of fishing gears, each with distinct implications for product quality, sustainability, and cost. Understanding these methods is crucial for buyers, as gear type often influences the grade of fish and its suitability for certain product forms (loins, steaks, etc.), as well as certification or eco-rating considerations. The major gear types for yellowfin include purse seines, longlines, pole-and-line/handline, and gillnets, with purse seine being by far the largest contributor to volumes.
Purse Seine
This is the workhorse gear of the global tuna industry. Large purse seine vessels (typically 50–100m in length) deploy enormous nets (up to 2 km in circumference) to encircle entire schools of tuna, then “purse” the net closed from the bottom. Purse seiners operating in tropical waters primarily target skipjack, but they also catch significant volumes of yellowfin – especially juvenile and medium-sized yellowfin that school with skipjack. Globally, purse seines account for roughly half or more of all yellowfin tuna catch. For example, in the Western Pacific, purse seining represented about 56% of the total yellowfin catch in 2023 (420,523 t out of ~746,000 t). Purse seine-caught yellowfin often comes from FAD sets (schools aggregating under man-made Fish Aggregating Devices) and free-school sets (unassociated tuna schools). FAD sets tend to yield smaller fish on average (juvenile yellowfin 3–10 kg, often incidentally caught in skipjack sets), whereas free-school sets can capture larger yellowfin mixed with adult skipjack.
In general, expect purse seine yellowfin to be Grade #2 or #3 – perfectly fine for grilling, canning, or cubing, but rarely the top choice for raw sashimi unless processed with color enhancement.
Sustainability & Bycatch
Purse seining is efficient but not without issues. FAD-based purse seining has drawn criticism for higher bycatch of non-target species (e.g., small tunas, sharks, billfish) and ecosystem impacts. Many yellowfin caught via FADs are juveniles that have not yet spawned, which can affect stock recruitment if unmanaged. RFMOs have responded by imposing FAD deployment limits and seasonal FAD fishing closures (e.g., 3-4 month FAD bans in the Pacific and Atlantic). Purse seiners are increasingly using non-entangling FADs to reduce ghost-fishing of sharks/turtles, and some are trialing biodegradable FADs to curb marine litter.
Longline
Longlining is the second most significant gear for yellowfin by volume. Longline vessels deploy lines that can stretch 50–100 km, bearing thousands of baited hooks at a depth of ~100m, to target large pelagic fish. Longlines primarily catch adult yellowfin (typically 25–100+ kg individuals) in deeper, open-ocean settings. Though longline contributes a smaller share of total catch than purse seine (for instance, in the Western Pacific, longline accounted for roughly 15–20% of yellowfin catch in recent years), it produces the highest quality tuna. Longline-caught yellowfin, often destined for sashimi or premium steak markets, are usually handled one by one upon retrieval: fish are landed alive, immediately stunned, bled, gutted, and chilled on ice or frozen.
Quality & Handling
There are two broad categories of longliners: fresh longliners (that ice or chill fish for fresh delivery) and freezer longliners (that super-freeze fish to ultra-low temperatures, -60°C, preserving sashimi quality). The latter are especially common in fleets supplying Japan. These super-frozen yellowfin loins (sometimes called “A+” loins) can retain near-fresh color and texture when thawed, making them suitable for high-end sashimi slicing or sushi. Longline fish often receive a quality grade by professional graders (based on core color, translucence, fat content, etc.): the very best yellowfin (Grade #1) – typically from longline – will be translucent deep red with high fat (often these fetch premium prices for Japanese sashimi). Lower grades from longline (#2, #3) go into steaks or processing.
Size matters – many markets prefer 10–30+ kg yellowfin for loin/steak production, since smaller fish yield loins that are thinner and paler. Longlines catch those larger sizes. Thus, if you are buying frozen saku blocks or high-end steaks, chances are the raw material was longline-caught.
Sustainability & Bycatch
Longlining has a very different impact profile. It has minimal impact on juvenile tunas (since it targets large fish), but the downside is bycatch of sharks, sea turtles, and seabirds. Circle hooks, monofilament leaders, and other mitigation measures are now widespread to reduce turtle catch and enable shark releases. Some longline fisheries – like those in the Pacific operated by Japan, Taiwan, USA, etc. – carry observers or use electronic monitoring to ensure compliance with bycatch rules. There are also time/area closures (e.g., certain Pacific zones closed for longlining to protect spawning bluefin or turtle hotspots).
Pole-and-Line & Handline
These are small-scale, one-by-one fishing methods often highlighted for their sustainability and artisanal nature. Pole-and-line involves fishers attracting tuna to the vessel with baitfish and water spraying, then catching them with barbless hooks on poles – flicking the tuna onboard in a rapid, rhythmic motion. Handline typically involves a single baited line tended by hand, often targeting larger individual fish (like the Maldives handline fishery for yellowfin). Combined, pole/handline fisheries take a modest portion of yellowfin – mainly in the Indian Ocean and parts of the Pacific.
Quality & Handling
These one-by-one methods often result in extremely high quality fish, because each tuna is individually handled and quickly iced. For instance, Maldivian fishermen in small dhonis will ice a large handline-caught yellowfin within minutes of capture. Many such fish are delivered fresh to processors who then export loins or fresh/chilled fish to markets (Maldives exports fresh/chilled yellowfin loins by air to EU and US). When exported as frozen, these are typically blast frozen shortly after landing on shore to preserve quality. Pole-and-line mainly catches smaller tuna (5–10 kg skipjack primarily), but any yellowfin caught are likewise promptly bled and iced. The result is that artisanal-caught yellowfin can be sashimi-grade (if handled well and super-frozen) or at least excellent “A” or “AA” grade for steaks.
Sustainability
Pole-and-line and handline are often touted as environmentally responsible methods with virtually no bycatch and no reliance on FADs. They are highly selective (catching target tuna one at a time) and have minimal impact on non-target species. These fisheries also generate important livelihood benefits in coastal communities like Maldives.
Gillnets and Other Gear
In certain regions, drift gillnets and coastal anchored gillnets catch a notable amount of yellowfin, though this gear is less visible in international trade. For instance, Iran, India, Sri Lanka, Pakistan and others in the Indian Ocean deploy large-mesh drift gillnets that collectively catch tens of thousands of tonnes of yellowfin annually. Gillnets are cheap and effective, but they are non-selective and often result in high bycatch and lower quality fish (tuna may struggle in nets for hours). Many gillnet-caught yellowfin are sold in regional markets or to processing plants for canning or lower-grade loins. International sustainability organizations have flagged drift gillnets as problematic.
The gear that caught your yellowfin tuna profoundly shapes its journey and end use.
- Purse seine = high-volume, cost-efficient, typically for canned or commodity frozen product (loins for canning, standard grill steaks, etc.), rarely sashimi grade. Often the most affordable option per kg.
- Longline = lower volume, higher value, yields premium quality loins/steaks (sashimi, sushi, high-end foodservice). Comes at a price premium but with superior quality.
- Pole-and-line/Handline = niche, sustainable, good quality, but limited supply. Often used for specialty products or brands emphasizing artisanal catch.
- Gillnet/others = we recommend caution; product may be lower grade and sourcing can be murky.
For a buyer, aligning gear type with product needs is key. If you need large volumes of competitively priced tuna for canning or manufacturing, FAD-free purse seine sources might be ideal. If you need sashimi-grade saku blocks, you’ll be looking at longline super-frozen fish. Easyfish can guide you through these options, ensuring you get the right balance of quality, sustainability, and cost for your specific application.
If you’re ready to source high-quality frozen yellowfin tuna or want a custom quote, visit our yellowfin tuna product page to get started today. You can also check out our full guide on yellowfin tuna sourcing and market dynamics.
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