White Marlin vs. Roundscale Spearfish: A Tale of Two Fish at the White Marlin Open

At this year's White Marlin Open in Ocean City, Maryland — the world's largest billfish tournament — the buzz isn't just about the million-dollar payouts or Michael Jordan’s Catch 23, 82' Bayliss making a high-profile appearance. It is also about the fish themselves, especially the often-misidentified duo: the white marlin and the roundscale spearfish.

Why are the white marlin and the round scale spearfish hard to tell apart?

Known collectively and colloquially as "hatchet marlin" due to their similar shapes and profiles, these two species are notoriously difficult to tell apart. Even seasoned anglers struggle without a trained eye — or a DNA test.

Both have long bills, rounded dorsal fins, and similar coloring. However, key differences lie in the lateral line (faint and wavy in white marlin, bold and arched in roundscale spearfish) and subtle body proportions. Another identifying difference is the difference between the anal vent and anal fin on the fish. On a white marlin the distance between the two is approximately two inches whereas the roundscale spearfish is usually around six inches.   The confusion is more than just cosmetic.

What are the consequences of mis-identifying a white marlin in the White Marlin Open?

Misidentifying a roundscale spearfish as a white marlin can affect tournament standings, conservation data, and scientific research. In fact, genetic analysis only confirmed roundscale spearfish as a distinct species in the early 2000s. This year’s tournament added a day of fishing, giving anglers more time to compete — and more chances to reel in a winning catch. With millions on the line, accuracy matters more than ever.

As conservation and sport fishing intersect, the importance of species identification grows. For now, whether it's a white marlin or a roundscale spearfish, one thing’s for sure: both continue to thrill anglers and scientists alike — and keep tournaments like the White Marlin Open full of mystery, excitement, and record-breaking competition. Remember to watch live here on our homepage to keep up with all the fishing excitement.