Anglers Await Arrival of Cobia, Tripletail
By DAVID RAINER
In a cherished ritual that happens each spring, the fish known by numerous names – cobia, ling, lemonfish, crab cruncher – comes lazily swimming along the beaches of the northern Gulf of Mexico en route to its summer haven amid the numerous oil and gas platforms in the western Gulf.
The annual migration usually reaches the Alabama coast in late March or early April. Because of the recent cold winter, the migration is a little behind schedule, according to the Gulf Coast Research Laboratory’s Jim Franks, who gave a CCA Fish Talk audience in Fairhope a wealth of information recently on this brute of a fish that can weigh in excess of 100 pounds. Alabama’s state record of 117 pounds, 7 ounces was caught by Capt. Ben Fairey in 1995.
Franks has been studying cobia for many years and has discovered that the fish are fast growing with a five-year-old fish averaging about 50 pounds. He said a 110-pound fish caught by Fairey off Orange Beach was aged at 10.
“These guys are always on the run,” Franks said. “They’re swimmers; they’re pelagic (open ocean). They grow fast and don’t live long compared to snappers. Females reach spawning maturity at two years old, about 33 inches. So the majority of these fish that participate in this annual migration are of spawning age.
“We’ve been tagging cobia for many years. Since we began our voluntary tag-and-release program 20 years ago, the longest tagging program in the Gulf, we’ve tagged a lot of fish. More than 80 percent of those fish have been tagged between Louisiana and the Big Bend in Florida. To date, 15,743 have been tagged. More than 1,000 of those have been recaptured.”
The recaptured fish show that the majority of fish make the migration run from south Florida to the northern Gulf in the spring and return in the fall. There is another migration route that takes cobia from south Florida up the Atlantic Coast to the Carolinas.
“What we’ve always wanted to know is what the fish do between the time they’re tagged and when they’re recaptured,” Franks said. “We do know that the fish migrate to our area in the spring and return to south Florida in the fall, although the fall run is in deeper water because we don’t see the fish along the beach in the fall.
“Interestingly in recent times, we’ve had a number of reports of people catching cobia in the wintertime in the northern Gulf. That’s when they should be in south Florida. We’ve actually caught some ourselves. What we’re beginning to think is there might be a group of cobia who spend the winter offshore in the northern Gulf. They are a non-migrating group of cobia. We’ve also found a group of cobia that spend the summer in southern Florida and don’t migrate.”
Franks said the recent utilization of pop-off satellite tags has increased the information available on cobia. The satellite data indicates the fish move back and forth from offshore structure to the beach and back during a six-month period.
“What we also learned that the fish spend a lot of time at the surface but also go down to about 150 feet and they appear to do it just about every day,” he said. “We also have some fish we can’t explain. We had one fish that went from the northern Gulf all the way down the West Coast to Mexico. We have no idea why.”
Franks said another tagged fish dove to the unusual depth of 400 feet while it was off the Texas Coast. After a little research, it was discovered the day the cobia dove so deep was the same day that Hurricane Claudette was headed for the Texas Coast.
“The fish just went deep to escape the hurricane,” he said.
Another of Franks’ favorite species is tripletail, or blackfish, which move inshore during the spring.
“The water temperature has just now reached 68 degrees along the coast, which is just about right for the lemonfish,” Franks said. “It’s been a cold winter and cold spring. But it’s time for the lemonfish, or ling, or cobia – whatever you want to call it – to get here. And the blackfish won’t be too far behind.
“The blackfish is a beautiful, beautiful fish in our waters,” Franks said “And Mobile Bay is one of the best places to fish for them in the entire Gulf of Mexico.”
Tripletail prefer to hang out in the shade of crab trap floats, channel marker poles, as well as sargassum grass lines. Although a 20-pounder is considered a big blackfish, there have been fish larger than 40 pounds landed.
“There are plenty of big ones out there and there are plenty of little ones, too,” Franks said. “The little ones are seen in a variety of colors. They like to get under structure, especially something floating. And they like to turn the color of whatever they’re floating under. That’s to their advantage because they’re ambush feeders.
“We found some a few years ago along a weed line and scooped up several with a dip net. We brought them back to our lab and actually raised them to good size in three years. The largest one we kept for five years and she got up to about 25 pounds.”
Franks and his fellow marine biologists spawned the large tripletail and started raising her offspring when Hurricane Katrina hit and the project was lost.
During his research, Franks discovered the otoliths (ear bones) in blackfish are much more difficult to analyze when trying to determine age.
“A band in an otolith usually represents a year in the fish’s life,” he said. “But, there is so much going on with the blackfish otoliths, that’s it’s hard to tell. To properly manage a fish, it’s important to know age structure, so we’re working on ways to better determine the fish’s age.”
What’s odd about tripletail, according to Franks, is that it’s a relatively short-lived species. The oldest blackfish on record, considering the difficulty of aging, is listed at only six years old.
“We know that snappers and groupers can live as long as 50, 60 years,” Franks said. “There was one yellowedge grouper aged at 85 years old last year. So six years for a fish to get to 30-40 pounds is rapid growth and a short lifespan.”
Franks is happy to see that Alabama and Mississippi have implemented management practices for blackfish. Alabama has a three-fish daily bag limit with a 16-inch minimum size. Mississippi also has a three-fish bag but with an 18-inch minimum size.
A voluntary tripletail tagging program has revealed some interesting data. Franks said during the summer most tripletail move very little, but in the fall they disappear to parts unknown.
“We don’t know where they go, but they show up the next year,” he said.
Other aspects of Franks’ tripletail research include: spawning potential, where they spawn and the extent of the spawning season.
“What we have learned is that tripletail are serial spawners,” he said. “They may spawn 30-40 times a summer. What we don’t know is how the spawning works, just that spawning likely occurs offshore. We’ve never caught a spawning female in Mobile Bay or Mississippi Sound.
“This is a very interesting species that we’re just now starting to learn a little about.”
PHOTOS (By Jim Franks): Jason Lemus, top photo, hoists a 65.5-pound cobia that was hovering around a marker buoy. Don Barnes found this 26-pound tripletail in the shade of a channel marker.