June 28, 2008

Previously Unknown Species of Economically Important Bonefish Found

MIAMI _ Fisheries scientists have known for years that two species of bonefish reside in the waters of South Florida and the Caribbean _ albula vulpes and albula garcia, or species B.

But before they could fill in the blanks of those respective life histories came recent confirmation from geneticists there is a third _ previously unknown and as yet unnamed _ species of one of the region's most economically important gamefish.

The new species cannot be identified by physical appearance _ only by examining DNA in the cell nucleus from bits of clipped dorsal fins. Geneticists at the Florida Fish and Wildlife Research Institute in St. Petersburg made the discovery recently based on samples taken from the Florida Keys; the western, undeveloped side of Andros Island in the Bahamas; Mexico's Yucatan region; the Virgin Islands; and Grand Bahama Island.

Experts who study the species, such as Aaron Adams of Mote Marine Laboratory on Pine Island in Sarasota, don't know where the mystery fish spends most of its time, when and where it spawns, how large it grows, nor when it reaches maturity. But they haven't answered some of those questions for the two previously identified species either.

"Figuring out what's in the fishery is a huge priority," said Adams, who serves as director of operations and research for the nonprofit Bonefish & Tarpon Unlimited.

"It's like being a kid in a candy store _ everything you find out is new, but you've only got a quarter."

Having the complete biological picture for bonefish is important because sport fishing is a multibillion-dollar economic engine in South Florida and the Caribbean. A five-year annual census conducted by scientists from the University of Miami shows every bonefish from Key Biscayne to the Marquesas in the lower Keys is worth $3,500 per year _ or $75,000 over its lifetime _ based on money spent on fishing tackle, boats and charters to chase the species.

Such a valuable resource must be managed properly, Adams said.

"You can't just say, 'There's a bonefish _ I know what its diet is, its habitat is, its growth rate is,' " Adams said. "You can't do that. It's worse to be wrong than to not know."

Discovering a new bonefish species is intriguing, but not surprising. Scientists previously discovered as many as nine species in the Pacific. Adams figures the South Atlantic/Caribbean's third species has been around for a long time, but it took DNA research to single it out.

Here's what Adams and his colleagues know about vulpes and garcia so far:

_They are suspected to spawn in deep, offshore waters around the full and new moons in winter and early spring. The larval phase is 42-72 days.

_About 96 percent of juvenile bonefish captured by scientists or caught by taggers in South Florida were garcia _ not vulpes, even though vulpes are the larger ones that comprise 98 percent of the flats fishery for bonefish. However, all 12 juveniles caught by researchers on North Bight on Andros Island were vulpes. All juveniles sampled at Turneffe Atoll in Belize were garcias.

_Two out of thousands of vulpes tagged in South Florida have been recaptured on Andros.

_Juvenile garcias are believed to live along shallow, sandy beaches while the juvenile vulpes live in deeper, open sand bottoms.

_Adult garcias are believed to live mostly in deep water, but have been found on the flats.

_Albula growth rates vary widely by region. For example, a 23-inch fish caught in the Keys was determined to be 6 years old, based on counting the rings on its otolith, or earbone, similar to the rings on a tree trunk. But the same-sized bonefish caught on Andros was 8 years old, and on the British Virgin Islands, 16.

_Bonefish diet varies by region. Hint: Try toadfish fly patterns for big bones in the Keys.

Said Adams: "We're proactive to say we don't know enough to manage these species. Let's figure it out."


To learn more about the state of the science of bonefish and tarpon, BTU will host an international symposium Nov. 14-15 at the IGFA Hall of Fame & Museum in Dania Beach and a public forum Nov. 16 at the Key Largo Marriott.


(c) 2008, The Miami Herald.

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