Roundscale Spearfish Fishing in Florida: ID, Rules & Risk

Until 2006, this fish officially didn’t exist. Every roundscale spearfish ever caught off Florida was logged as a white marlin — until genetic and anatomical work split the two, and scientists realized a large share of the Atlantic “white marlin” catch had been this species all along. The roundscale is the impostor in plain sight: same size, same water, same spread. And it swims in dangerous company, because its own genus holds two spearfish that Florida prohibits outright. Getting this ID right is not trivia — it is the difference between a lawful billfish and a prohibited fish in your hands.

This guide gives the roundscale spearfish its own page: the field marks that separate it from white marlin and from its two prohibited cousins, where and when it runs with the summer billfish, how it is caught, and the regulation — the standard FWC billfish framework at 66 inches, with the prohibited-congener warning stated as plainly as FWC states it.

If you take one thing from this page, take the pattern: a long, low first dorsal and scales broad and rounded at the rear edge — and if the spearfish in front of you has a truly long bill, stop: that fish is prohibited.

Where to Catch Them

Wherever the white marlin are — because for a century they were counted as the white marlin. Roundscale spearfish run the Atlantic slope off Florida in summer, working the same temperature breaks, weed lines, and bait concentrations as whites, in the same mixed aggregations. Fisheries scientists working the mid-Atlantic catch found roundscales making up a substantial fraction — in some samples a majority — of the fish logged as white marlin, and Florida’s summer water holds both species in the same proportions.

Zones and habitat

• Temperature breaks on the slope: the 100- to 300-fathom edges off Stuart, Palm Beach, and Fort Pierce in summer — the heart of the shared white/roundscale water.
• Keys blue water: the deep side of the reef from Islamorada to Key West, mixed with summer whites.
• Weed lines and bait balls: the same hunting structure as every summer billfish — bait first, predators behind it.
• The whole summer spread: any Florida boat trolling ballyhoo for white marlin is fishing roundscale water whether it knows it or not.

Gulf vs. Atlantic vs. Keys

Atlantic and Keys, as with the white marlin it shadows. The Gulf produces occasional spearfish reports in the northern canyon country, but the Florida fishery — such as it is, conducted almost entirely under the white marlin’s name — is the southeast coast and Keys in summer. Its showier inshore cousin by season is the sailfish; the spearfish is strictly an offshore summer companion to the whites.

Access without a boat

None. This is a deep-water summer billfish; boats only, and mostly boats that think they are white marlin fishing.

When to Catch Them

Summer, with the whites: June through September off Florida’s Atlantic coast, when the mixed billfish body moves along the breaks. There is no separate roundscale season because there has never been a separate roundscale fishery — the fish is encountered inside the white marlin season, the white marlin grounds, and very often the white marlin’s logbook entry. On the day, bites mirror the whites’: flurries around bait and tide movement.

How to Catch Them

Exactly as you catch white marlin — because that is what everyone catching them is doing. Ballyhoo on circle hooks behind dredges and teasers, live baits pitched to raised fish, 20- to 30-pound tackle on the summer breaks. Roundscales fight like whites: fast, jumpy, greyhounding across the surface. The fishing is identical; everything about this species happens after the hookup, at boatside, with the fish in hand and the ID to make.

The ID that matters, in full. Three spearfish live in this conversation. Roundscale spearfish (this fish, lawful): first dorsal long and low, running along the back without the white marlin’s tall rounded sail; anal fin broad with a blunt tip; and the diagnostic anatomy — scales broad with distinctly rounded rear edges (run a hand backward along the flank: roundscale scales feel broad and smooth-tipped), and the anus set well ahead of the anal fin’s origin. White marlin (lawful, same 66-inch rule): tall, rounded dorsal lobe, rounded anal fin, anus close to the anal fin. Longbill spearfish and Mediterranean spearfish (PROHIBITED — unlawful to harvest, possess, or land): the longbill wears a bill dramatically longer than either lawful fish, and the Mediterranean is a rare stray whose ID demands the same scale-and-anatomy work. When the bill on a spearfish looks wrong — too long, too heavy for the body — the fish goes back, period.

On the table, honestly. Like the white marlin, a release fish. A lawful roundscale inside the framework below may be kept, but the species spent a century as a data error; the fleet’s norm is boatside release, and this site endorses it — especially because any spearfish whose ID you are unsure of should be released on the doubt alone.

Florida Regulations

Roundscale spearfish is a lawful billfish under FWC’s standard billfish framework:

Rule	Gulf and Atlantic
Minimum size	66 inches lower jaw fork length (measured from the tip of the lower jaw to the fork of the tail)
Daily bag	1 billfish per person — an aggregate across all billfish species, not one per species
Season	Open year-round
Gear	Hook and line only
NOAA reporting	All landed (kept) billfish must be reported to NOAA within 24 hours — 800-894-5528 or hmspermits.noaa.gov
Federal HMS permit	Required in federal waters. NOT required for billfish in state waters

FWC’s Billfish, Tuna and Swordfish page and its official chart both print the roundscale’s 66-inch minimum inside the billfish framework — same aggregate bag, same year-round season, same hook-and-line rule, same 24-hour reporting of landed fish, same federal-waters HMS permit with no permit required for billfish in state waters. Roundscale spearfish itself is not on any FWC prohibited list.

But its genus-mates are, and this is the most dangerous ID line in the wave. FWC’s prohibited list makes it unlawful to harvest, possess, or land the longbill spearfish and the Mediterranean spearfish — two of roundscale’s three closest relatives. “Spearfish” is therefore never one answer: Tetrapturus georgii (roundscale) takes the billfish rules above; T. pfluegeri (longbill) or T. belone (Mediterranean) must be released, always, at any size. The Keeper Checker keys spearfish by species for exactly this reason. If the ID will not resolve on the marks in the section above, release the fish — that rule has no exceptions worth a prohibited possession.

Regulations verified against FWC, October 2026 — always confirm current rules at myfwc.com before you fish.

Quick Facts

• Scientific name: Tetrapturus georgii
• Also known as: hatchet marlin; recognized as its own species only in 2006, after a century counted as white marlin
• Max size in Florida: most run 40 to 90 pounds, in white marlin’s exact size band
• Table quality: a release fish — and any doubtful spearfish ID is a release by definition
• Fight quality: pure white-marlin class — greyhounding jumps and light-tackle runs
• Status: lawful under FWC’s billfish framework (66″ LJFL, 1-billfish aggregate, 24-hour NOAA reporting) — while its longbill and Mediterranean cousins are prohibited outright

Related Species

Other offshore fish Florida crews chase in the same blue water include Sailfish, Swordfish, Yellowfin Tuna and Bigeye Tuna.

See the exact hooks, baits and rigs for Roundscale Spearfish in the Tackle & Bait Picker.