[MARINE_BIOLOGY_INTERNATIONAL] Bonefish mating still secretive


Miami, FL - University of Massachusetts Amherst scientist Andy Danylchuk rocked the flats-fishing world in May when he became first to document bonefish spawning behavior in the Bahamas.

The study, conducted in Eleuthera and published in the journal Marine Biology, described how the shallow-water speedsters gather in schools of more than 1,000 for a few days around the full and new moons from October to May, then head offshore to waters more than 1,000 feet deep to reproduce at night. Researchers took video of bonefish leaping out of the water like porpoises as they headed offshore and theorized this might be courtship behavior.

Fisheries scientists in South Florida long have believed that bonefish in Biscayne Bay and the Keys follow similar spawning behavior patterns but have yet to document it.

Which raises an interesting question about what captain Carl Ball and I witnessed on a Biscayne Bay flats fishing outing June 22.

The tide on the east side of Elliott Key when we arrived in late morning was low and just starting to come in. Ball, standing atop the poling platform of his skiff, spied a dark, mottled cloud in the water off a sandbar that extends from the island. Not knowing what to look for, anyone else probably would have mistaken it for tufts of sea grass on the bottom.

But Ball correctly identified it as a large school of bonefish milling around slowly back and forth along the island's edge in about five feet of water — some floating near the surface.

I made several casts of my 9-weight with Bahamas-like shrimp fly into the throng with no result. Each time the school would get close to the skiff, it would veer slowly away — but not panicking and remaining fairly close to shore.

Ball would pole the skiff from the fish to give them time to relax, then head slowly back to within casting range.

I cast my fly to the edge of the school as we got closer — and hooked a small, annoying jack. It's not unusual to find jacks mingling with bonefish.

After unhooking the jack and letting the bonefish settle down, Ball poled toward them once again. This time, I put the fly in the center of the school — which had to number into the hundreds — and was rewarded with squealing drag and disappearing line that quickly went into the backing.

At first, Ball feared it might be another pesky jack. But when it made a scorching 100-yard dash, we figured I finally had hooked the right species.

After about a 10-minute battle, I brought the bonefish close enough for Ball to grab, and he unhooked it and stuck it in his livewell.

Ball, a 10-year-veteran flats guide in the bay, tags his mostly fly-caught bonefish, tarpon and permit for scientific research conducted by Bonefish & Tarpon Trust and the University of Miami Rosenstiel School. This would be his 40th tagged bonefish of the year.

He got out his tagging gun and data sheet as I leaned forward to take photos of the process.

But when Ball lifted the bonefish from the well, it expelled a substance that could only be gametes onto the deck. It also sprayed the steering wheel.

We both assured the fish that we would make haste with the tagging process so that it could resume trying to get lucky. Ball injected a tag behind its dorsal fin and measured it — 22 ½ inches to the fork, estimated size: 6 pounds — then recorded the tag number and length on a sheet. He also made a note about the spawning fluid.

When Ball put the fish back into the bay, it bucked in his hands and pulled away before he could try to revive it. A healthy fish, and obviously eager to get back to what it was doing before it mistakenly ate the fly.

After that, we tried for permit, but that's another story.

The next day, I called Aaron Adams, Bonefish & Tarpon Trust director, to tell him what happened.

Adams said there have been anecdotes from the Bahamas of bonefish seen spawning into June, but the reproductive habits of South Florida fish still are unknown.

"I wouldn't call it a pre-spawning aggregation because it wasn't on the full or new moon," Adams said of the Elliott Key school of fish, which appeared the day before the third-quarter moon. "There could be some fish that might still spawn. Or there are some fish that are done spawning so they are reabsorbing the gametes. When you get into behavioral stuff like this, there's so much that could be going on."

For the sake of the bonefish (and those who take pleasure in stalking, catching and releasing them), I hope they spawn as often as they can. The species took a hit with the deep freeze of January 2010. Last fall's bonefish census conducted in Biscayne Bay and the Keys by scientists, anglers and guides showed a reduction in numbers. And no one knows how their larvae might have been affected by last year's BP oil disaster in the Gulf.

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