Blue Marlin vs White Marlin: How to Tell Them Apart

Blue marlin vs white marlin? Size is the quickest clue: blue marlin average 200 to 400 pounds, while white marlin usually run 50 to 80 pounds. For a closer call, check the dorsal fin and bill. A blue marlin has a pointed dorsal fin and a short, thick bill; a white marlin has a tall, rounded dorsal fin and a long, slender bill. Blues live in the Atlantic and Pacific; whites live only in the Atlantic.

Below is a side-by-side table, how to tell them apart on the water, and how anglers fish for each. Offshore angler? Browse our marlin fishing shirts.

Blue marlin vs white marlin at a glance

Table source: FishingBooker's guide to blue marlin vs white marlin.

How to tell blue marlin vs white marlin apart

1. Size

FishingBooker notes that blues average 200 to 400 pounds while whites reach just 50 to 80, and that "even a trophy White Marlin isn't likely to top 150 pounds." The catch: a small blue and a big white can look alike, so use the next clues too.

2. Dorsal fin

When you cannot see the whole fish, the fin is the best tell. Blue marlin have a pointed peak; white marlin have a tall, rounded dorsal fin. The anal fins follow the same pattern.

3. Bill and body

Blues are stocky with a short, thick bill. Whites are slim with a long, slender bill.

4. Color is the least reliable clue

Despite the names, both fish have dark cobalt backs and pale sides, and either can show faint stripes. Do not identify by color alone.

Where do blue and white marlin live?

Blue marlin live in both the Atlantic and the Pacific and follow warm currents over long distances. White marlin are found only in the Atlantic and tend to come closer to shore, around drop-offs, canyons and the edge of the continental shelf. The Mid-Atlantic coast is known for some of the best white marlin fishing.

Also watch for look-alikes. A Florida Keys charter guide notes that proper identification "also requires distinguishing white marlin from similar billfish, including roundscale spearfish."

Fishing for blue marlin vs white marlin

FishTrack calls blue marlin "often considered the most challenging of all the billfish to catch," with explosive runs, greyhounding jumps and head shakes. White marlin are "fast, agile and tough to hook" and are one of the smallest billfish, so most crews target them with 20- or 30-pound tackle (FishTrack billfish identifier). Both are usually targeted by offshore trolling. Check current permit and catch-and-release rules for your area before your trip.

Heading offshore? Our guide on what to wear deep sea fishing covers sun, spray and layers.

Marlin shirts for your next offshore trip

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FAQ

What is the difference between a white marlin and a blue marlin?

Blue marlin are much larger, stockier, with a pointed dorsal fin and short thick bill. White marlin are slimmer, with a tall rounded dorsal fin and a long slender bill, and live only in the Atlantic.

Which is bigger, blue or white marlin?

Blue marlin. They average 200 to 400 pounds, while white marlin usually weigh 50 to 80 pounds.

Can you tell marlin apart by color?

Not reliably. Both have dark cobalt backs and pale sides. Use size, dorsal fin shape and bill instead.

What is so special about white marlin?

They are fast, acrobatic and hard to hook, which makes them one of the most loved game fish on the U.S. East Coast.