When Bonefish Go Deep

These gray ghosts are the kings of the flats. But their spawning behavior might surprise you.

- Nick Roberts

Silver tails slicing a flat's glassy surface at daybreak. A subtle V-wake moving along a mangrove-fringed shoreline. A trio of gray silhouettes gliding silently toward the bow over white sand. These are just a few of the scenes that come to mind when anglers think about bonefish, a species that has evolved over millennia to thrive in the shallows.

The gray ghost rarely ventures out of its comfort zone; in tagging studies by Bonefish & Tarpon Trust, a Florida-based conservation organization, 70 percent of recaptured bonefish were caught within 1 kilometer of where they were initially tagged.

Migrating to Spawn

But it's a different story come spawning season, which spans fall to spring. During full-and new-moon cycles, bonefish leave the relative safety of their home flats and travel great distances to nearshore areas, where they form giant schools called pre-spawning aggregations (PSAs) that number thousands of fish. BTT documented bonefish migrating as far as 70 miles to reach a PSA site, a remarkable feat for a fish that rarely weighs more than 10 pounds.

Bonefish in the PSA prepare to spawn by gulping air at the surface to fill their swim bladders. Then at night, they swim offshore and dive hundreds of feet in water that can be thousands of feet deep. Just think about that for a moment-a fish designed for the flats descending