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Photo of a Blue Marlin

Species profile

Blue Marlin

Makaira nigricans

Bony fishIUCN: Vulnerable202 iNat observations

At a glance

Blue Marlin (Makaira nigricans) is an IUCN Vulnerable bony-fish species regulated in 6 of 66 jurisdictions tracked by CatchRules across the U.S. and Canada.

Bag limits are uniform at 1 per angler across the 3 regulating jurisdictions.

Across 3 jurisdictions with stated minimum sizes, the average minimum is 98.7 in (≈ 8 ft 3 in).

Confirmed by 12 research-grade iNaturalist observations, with Hawaii, Florida, and Mississippi the top jurisdictions by observation count.

Notable details

  • Females can reach 14 feet (4.3 m) long and exceed 1,400 lbs (635 kg).
  • Males rarely top 300 lbs (136 kg), making females up to five times heavier.
  • Uses its long, spear-like bill to slash through schools of baitfish before circling back to eat.
  • Highly migratory, tracking warm ocean currents across entire ocean basins throughout the year.
  • Keeps its brain and eyes warmer than surrounding seawater using a specialized counter-current heat exchanger.

Background

The Atlantic blue marlin (Makaira nigricans) is a species of marlin endemic to the Atlantic Ocean. It is closely related to, and usually considered conspecific with, the Indo-Pacific blue marlin, then simply called blue marlin. Some authorities still consider both species distinct.

Background excerpt adapted from Wikipedia's Blue Marlin article (CC BY-SA). Visit Wikipedia for the full entry.

Photo credit: iNaturalist / Wikipedia. Identification reference only — verify regulations with the issuing wildlife agency before retaining a catch.