How Big Does Bluefin Tuna Have to Be to Keep?

To keep an Atlantic bluefin tuna, the fish must measure at least 27 inches curved fork length (CFL), and how big it can be depends on your permit. So how big does a bluefin tuna have to be to keep? Recreational anglers on an HMS Angling or Charter/Headboat permit can retain one fish measuring 27 to less than 73 inches CFL per vessel per day, plus one “trophy” fish of 73 inches or greater per vessel per year. Commercial permit holders generally can only keep fish 73 inches CFL or larger. Pacific bluefin tuna are managed under a separate system with different rules.¹

The Five Size Classes

NOAA Fisheries sorts Atlantic bluefin tuna into five size classes by curved fork length, and every regulation you’ll read uses these names:

School: 27 inches to less than 47 inches CFL
Large school: 47 inches to less than 59 inches CFL
Small medium: 59 inches to less than 73 inches CFL
Large medium: 73 inches to less than 81 inches CFL
Giant: 81 inches CFL or greater

No one may retain a bluefin under 27 inches CFL. That floor applies to every permit type, every gear type, and every area.¹ Above 27 inches, the size class controls whether you can keep the fish, how many you can take, and whether you can sell it.

Recreational Keeper Sizes

With an HMS Angling permit (private vessel) or an HMS Charter/Headboat permit fished recreationally, the default limit is one bluefin measuring 27 to less than 73 inches CFL per vessel per day or trip. That single fish can come from the school, large school, or small medium class. You can’t have more than one day’s limit on board when you return to the dock, no matter how long the trip lasts.²

The limit is per vessel, not per angler. Headboat passengers sometimes learn this the hard way: ten people on the rail still share one fish.

Separately, recreational anglers get one “trophy” bluefin of 73 inches CFL or greater per vessel per year. That covers both large medium and giant fish. The trophy fishery is split into regional sub-quotas (Gulf of Maine, Southern New England, South, and Gulf of America), and any region can close independently once its share is landed.²

NOAA Fisheries adjusts the recreational retention limit through the season based on quota. In recent years mid-season increases have temporarily raised the limit to two or three fish per vessel in certain areas when quota remained available.³ So the “one fish, 27 to less than 73 inches” answer is the baseline; the number in force on the day you fish may be different.

One rule catches people off guard: you cannot retain any bluefin tuna if a hammerhead shark is on board or has already been offloaded from the vessel during that trip.²

Commercial Keeper Sizes

Commercial permits have a higher size floor. Under an Atlantic Tunas General or Harpoon category permit, only large medium and giant fish (73 inches CFL or greater) may be retained, possessed, or sold. School, large school, and small medium bluefin cannot be kept on a commercial trip at all.⁴

How many of those 73-inch-plus fish you can take depends on category and time of year. General category vessels default to one large medium or giant per vessel per day from January through March and July through December, and three per day during June, with NOAA Fisheries able to adjust the limit anywhere from zero to five per day based on quota.⁴ Harpoon category vessels currently run at five large medium and giant per vessel per day, with no more than two of those being large medium (73 to less than 81 inches), and the regulations allow adjustment across a range of five to ten per day.⁵

An HMS Angling permit does not authorize sale of any bluefin. To sell a fish you catch, you need a commercial permit; Charter/Headboat permit holders who want to sell need a commercial sale endorsement.⁶

Gulf of America Is Different

NOAA Fisheries treats the Gulf of America as bluefin tuna spawning grounds and does not allow targeted bluefin fishing there. Recreational anglers in the Gulf may not retain any school, large school, or small medium bluefin (27 to less than 73 inches CFL). The only fish that can come home is one large medium or giant (73 inches or greater) per vessel per year through the incidental trophy fishery, and only while the Gulf of America trophy sub-quota is open. Once it closes, no bluefin of any size may be kept in the Gulf.⁴

Pacific Bluefin Tuna

Everything above is Atlantic. Pacific bluefin tuna are managed by the Pacific Fishery Management Council under international agreements with the Inter-American Tropical Tuna Commission, not through the Atlantic HMS system. For recreational anglers, the rules differ dramatically: in many Pacific coast areas there is currently no minimum size limit for recreationally caught bluefin tuna, though daily bag limits and seasonal restrictions apply. Because Pacific bluefin regulations change frequently and vary by state, check your state’s ocean fishing regulations and the PFMC before you fish.

How to Measure Curved Fork Length

The size class of a whole bluefin is determined by curved fork length, not straight length.⁷ Lay a flexible tape along the body following its natural contour, starting at the tip of the upper jaw and running along the curve to the fork of the tail.⁵ A straight-line measurement gives you the straight fork length, which is shorter and is not what enforcement uses. If you pull the tape tight, you can fail a legal fish; if you measure the wrong way, you can also keep an illegal one without knowing it.

If the head has been removed, size class is determined using pectoral fin curved fork length (PFCFL) multiplied by a conversion factor of 1.35.⁷ Measure on the boat before you process the fish. Measurement disputes at the dock almost always go against the angler.

What Happens If the Fish Is Undersized

Under NOAA’s National Summary Settlement Schedule, possessing an undersized bluefin brings the following penalties:

Recreational, first offense: $500 per fish, for up to five fish
Recreational, second offense: $1,000 per fish, for up to five fish
Commercial, first offense: $1,000
Commercial, second offense: $2,000

Beyond the fine, violations can lead to permit suspension or revocation. Enforcement officers cross-reference dealer reports with vessel catch reports, so unreported or misreported landings tend to surface.⁸

Check Before You Leave the Dock

Bluefin retention limits shift more often than almost any other fishery. NOAA Fisheries changes limits, opens and closes sub-periods, and adjusts quotas throughout the year, and a category can close on short notice once its allocation is landed. The January through March General category sub-period, for example, closed roughly two weeks into 2026 after its 37.7-metric-ton quota was reached.⁹ The rules are codified at 50 CFR Part 635, but the number you can keep on any given day is set by the current status of the fishery.¹⁰ Before every trip, check the NOAA Fisheries recreational and commercial status pages for the size and retention limits in effect that day.

1
eCFR. 50 CFR 635.20 – Size Limits
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NOAA Fisheries. Recreational Atlantic Bluefin Tuna Fishery Statuses and Bag Limits
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NOAA Fisheries. Retention Limit Adjustment – Atlantic Bluefin Tuna Angling Category Fishery
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eCFR. 50 CFR 635.23 – Retention Limits for Bluefin Tuna
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NOAA Fisheries. Commercial Atlantic Bluefin Tuna Fishery Statuses, Minimum Sizes, and Retention Limits
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NOAA Fisheries. Frequently Asked Questions – Atlantic Highly Migratory Species Permits
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eCFR. 50 CFR 635.20 – Size Limits
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NOAA Fisheries. Atlantic Highly Migratory Species Reporting
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National Marine Fisheries Service. NMFS Permit Shop News
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eCFR. 50 CFR Part 635 – Atlantic Highly Migratory Species