White marlin fishing out of Marathon starts with knowing where the deep structure sits. This is the named ground off Marathon and Key Colony Beach, with depths in feet. Use the depths as reference points for your own waypoints.
The deep humps off Marathon
Two named humps sit in the deep water off the Middle Keys. Both carry more than one name, so a search under either one finds the right spot.
Marathon Hump (Marathon West Hump)
The Marathon Hump, also called the Marathon West Hump, has a shallowest point of 480 ft. Plot that crest against the bottom around it.
409 Hump (also listed as the 408 Hump)
The 409 Hump, also listed as the 408 Hump, is named as a top Middle Keys blackfin tuna spot.
Bridge and reef structure inside the humps
Shallower named structure sits closer to the keys. The table lists it by depth, deepest first.
| Name | Depth | Type |
|---|---|---|
| Thunderbolt | 120 ft | Structure |
| Marathon Reef Site | 100 ft | Bridge rubble |
| Seven Mile Bridge Reef | 90 ft | Bridge spans and concrete |
| Long Key Reefs | 24 and 26 ft | Bridge spans and concrete |
Thunderbolt
Thunderbolt is structure in 120 ft, 4 miles south of Marathon and Key Colony Beach.
Marathon Reef Site
The Marathon Reef Site is bridge rubble at 100 ft.
Seven Mile Bridge Reef
Seven Mile Bridge Reef is bridge spans and concrete at 90 ft.
Long Key Reefs
Long Key Reefs are bridge spans and concrete at 24 and 26 ft.
The named structure shows on the Chart Contours layer. Chart layers are not for navigation.
Season, methods and the wider white marlin picture
The white marlin species guide covers timing, behavior and technique. For the regional picture, see white marlin in the Atlantic Southeast (see also the wider Atlantic Southeast guide). The billfish guides place white marlin alongside the other billfish species.
FAQ: white marlin fishing out of Marathon
How deep is the Marathon Hump?
The Marathon Hump, also called the Marathon West Hump, has a shallowest point of 480 ft.
Is it the 408 Hump or the 409 Hump?
Both names refer to the same spot. It is listed as the 409 Hump and as the 408 Hump, and it is named as a top Middle Keys blackfin tuna spot.
Where is Thunderbolt?
Thunderbolt is structure in 120 ft, 4 miles south of Marathon and Key Colony Beach.
What is at Seven Mile Bridge Reef and the Marathon Reef Site?
Seven Mile Bridge Reef is bridge spans and concrete at 90 ft. The Marathon Reef Site is bridge rubble at 100 ft.
Where are the rules for white marlin fishing out of Marathon?
FWC sets the state rules and NOAA Fisheries sets the federal rules. The Regulations section above points to both, so check them before you fish.
