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Entries in DNA (12)

Wednesday
Oct112017

Bullards Bar Spot Finally Recognized as Record By Both California and IGFA

California and the International Game Fish Association (IGFA) finally are in agreement. The 11-pound, 4-ounce (11.25)  Alabama spotted bass caught by Nick Dulleck in February 2017 on Bullards Bar Reservoir is both a world and state record.

For IGFA, which recognized the catch in May, the previous world record had been 10.38 pounds, also taken at Bullards Bar. But a 10.95-pound fish caught at the same fishery in 2015 had been recognized by California. IGFA had disqualified that fish because its original weight was reported as 11.2.

In recent years, reports have surfaced regularly of other fish being caught that would have been state records, but the reporting process was so cumbersome that anglers didn't want to participate. In particular, they didn't want to kill the fish, either for DNA sampling or because a biologist wasn't immediately available to certify the catch.

Dulleck, however, was prepared, rolling video from cast to release, including weighing the fish on a certified scale in front of witnesses. He is now working with California Department of Fish and Wildlife (DFW) to make state certification easier for other anglers.

"I didn't want this record to just be about me," he said. "I've worked with the IGFA and the California DFW a lot through this whole process. They have been great to work with. If I can help make the whole process better for all anglers, then I really want to do that. Then I will have done something that matters." 

Monday
May042015

Lionfish Threat Continues to Spread

As harmful invasive fish species, Asian carp seem to garner most of the headlines, mostly because of the threat that they pose to the Great Lakes.  But the lionfish, a marine invader from the Pacific Ocean, is decimating native species through much of the Caribbean, as well as spreading up the Atlantic coast and across the Gulf of Mexico. (See previous post.)

And now it’s been discovered off the coast of Brazil, which suggests the entire  coast of South America likely will be invaded.

“When the researchers analysed the fish’s DNA, they found that it matched the genetic signature of the Caribbean lionfish population, and not that of specimens from their native Indo-Pacific region. This suggests that the fish may have reached Brazil through natural larval dispersal from the Caribbean, the study’s authors say,” reports Nature.

“But Mark Hixon, a marine ecologist at the University of Hawaii at Manoa, says that ocean currents typically flow in the wrong direction for larval dispersal from the Caribbean to the southeastern Brazilian coast. He says that it is just as likely that the lionfish was brought to Brazil by humans. ‘Lionfish are easy to capture and make beautiful pets,’ says Hixon. ‘It’s easy to imagine boaters carrying lionfish as short-term pets in bait tanks or other containers on their vessels.’”

The Invasive Species Action Network adds this:

“Lionfish are vicious predators that eat any fish or invertebrate they can fit in their mouth. They reproduce easily and the rate at which they have expanded their range shows that they are thriving in this environment. With no predators in our waters they are rapidly impacting many habitats.

“Humans can have an impact. Fortunately, lionfish are very tasty and many restaurants have added them to the menu. In many areas concentrated spearfishing is keeping local populations in check but this is not a practical method of control across their range. In the USA, NOAA is the lead agency on this problem and they are the best source for lionfish information and research.

“NOAA has recently released the draft National Invasive Lionfish Prevention and Management Plan While the plan is still in draft form, it is scheduled to be approved at the next meeting of the Aquatic Nuisance Species Task Force meeting scheduled for the first full week in May.”

Wednesday
Apr292015

Survey Reveals Carp DNA Throughout Chicago Waterway System

If Asian carp aren’t in the Great Lakes, they can’t get much closer. Sampling of the Chicago Area Waterway System (CAWS) last fall revealed carp eDNA throughout the system, including near a lock in downtown Chicago, just one block from Lake Michigan.

“Prevention needs to happen now and the U.S. Army Corps of Engineers and other key decision-makers should take swift action,” said the non-profit Alliance for the Great Lakes (AGL), which charges that the Corps lacks direction, as revealed in its Great Lakes-Mississippi River Interbasin Study.

“DNA evidence is an early detection tool to understand the potential movement of carp, and testing results have consistently found DNA hits on a path closer and closer to the Great Lakes over the past several years of testing,” the group added.

The Corps report outlined eight possible ways to stop migration of Asian carp into the Great Lakes, with the most expensive being an $18.3 billion separation of the CAWS from Lake Michigan. Meanwhile, the Alliance supports measures to temporarily reduce risk, including construction of a new channel and control technologies in the approach to Brandon Road lock and research on reconfiguration of locks in general.

But long-term issues with Chicago’s water system infrastructure must be addressed to keep the carp out, emphasized Jennifer Caddick, AGL spokesperson.

“It’s complicated. You can’t just build one dam and solve the whole problem,” she said. “There’s a lot of work to be done, but we need intensive focus.”

If/when Asian carp become established in the Great Lakes, consequences could be catastrophic for the multi-billion-dollar sport fishery. That’s because the exotic fish are fast-growing, prolific, plankton eaters. They likely would outcompete the many young and adult native fishes that rely on phytoplankton and zooplankton for their primary forage.

Additionally, the U.S. Geological Survey has identified 22 rivers in the U.S. portion of the Great Lakes that would provide suitable spawning habitat for Asian carp.

Thursday
Jan082015

DNA Research Reveals Trophy Bass Parentage at Guntersville

Contrary to popular belief, Guntersville trophy bass are not pure Florida strain, according to DNA research conducted during the 2014 Bassmaster Classic at that northern Alabama fishery.

From a scientific standpoint, however, that really isn’t surprising. Between 1981 and 1994, an estimated 500,000 Florida bass were released into Guntersville, but few have been added since.

“The population, instead, consists largely of hybrid crosses,” said Dr. Eric Peatman, an associate professor in Auburn University’s School of Fisheries, Aquaculture, and Aquatic Sciences.

Eight-pound-plus fish are 52 percent Florida and 48 percent northern. That’s in keeping with the assessment of Gene Gilliland, B.A.S.S. National Conservation Director, who said that bass with 50 percent or more Florida genes have enhanced trophy potential. “Below that, and it’s no greater than for native fish,” he added.

Peatman and his team also found that the “lakewide average genetic composition” is about 70 percent northern and 30 percent Florida.

“Four to five-pound fish do not vary significantly from the lakewide average in their genetic make-up,” he explained. “However, seven-pound-plus fish show an increase in Florida percentage to 42 percent of their genome.”

These findings suggest that stocking Guntersville with Florida bass has been effective in shifting the genetic baseline of the population and that trophy-size fish are bunched around a rough 50:50 genetic split, said Peatman, adding that more samples are needed to reach definitive conclusions.

“One of the missing components in this analysis is age,” the scientist said, adding that multiple ages likely are represented among those samples of larger bass. “Ultimately, we want to know what is the genetic composition of the largest size fish within each year class, or what mix of Florida and northern alleles produces the fastest growing fish.”

The Alabama Department of Conservation and Natural Resources (ADCNR) will with this aspect during its spring sampling.

“A final component in the mix is obviously habitat,” Peatman said. “The best performing genotype in one reservoir is not necessarily the best genotype in a different reservoir with different environmental parameters. “So we have plans to include different reservoirs and habitats in the analysis in the coming year as well.”

All of this work is part of a statewide project funded by ADCNR to better understand the impacts of the state’s Florida bass stocking program on the quality of its bass fisheries.

“The Classic and other tournaments throughout the year in Alabama represent an excellent opportunity to take non-lethal DNA samples from larger bass brought in by anglers,” Peatman said.

“At the end of the day, the goal is to use these genetic tools to help ALDCNR make proactive stocking and management decisions to ensure the highest quality bass fisheries for our anglers for years to come.”

(This article appeared originally in B.A.S.S. Times.)

Wednesday
Aug272014

Future Bright for Trophy Bass in Florida, Texas

The best is yet to come for anglers who pursue big bass in Florida and Texas. Even though they have decidedly different approaches, each sponsors a program that optimizes opportunities provided by the Florida strain of largemouth.

Of course, it’s only logical that the two have differing strategies, since one manages for non-native fish in manmade impoundments, while the other focuses on native fish in natural lakes. As a consequence, Texas constantly researches methods for growing more and ever larger bass, while Florida has set up a system that both helps anglers find the state’s biggest fish and encourages catch-and-release.

Implemented just two years ago, the Sunshine State’s TrophyCatch still is in its “infancy stages,” according to Bill Pouder, a freshwater fisheries administrator for the Florida Fish and Wildlife Conservation Commission (FWC). It was borne out of the state’s Long-Term Black Bass Management Plan, with the intent of ensuring “Florida is the undisputed bass fishing capital of the world.”

Word of mouth, Pouder added, has helped considerably in motivating fishermen to report catches of 8 pounds and larger. “If I’m an angler who catches an 8-pound bass and all I have to do is provide a photo and measurements in exchange for $100 in gift cards and prizes, then I’d be very encouraged to do it,” he said.

Statistics certainly bear out that assessment, too. From Oct. 1, 2012, through September 2013, fishermen entered 206 fish in TrophyCatch. But 679 bass were logged in during the eight months that followed. Of those 885 fish, 244 weighed between 10 and 12.99 pounds and 5 weighed 13 pounds or more.

As possibly the biggest surprise of the program thus far, three of those latter fish, including the largest at 14-9, came from Kingsley Lake, a semi-private fishery in Clay County. That discovery goes to the heart of how TrophyCatch will enhance opportunities for Florida anglers to catch lunkers: It tells them where they are.

Not so surprising is that Lake Istokpoga tops the list of public waters, followed by Okeechobee, Toho, Kissimmee, and St. Johns River. But 235, or more than 25 percent, of those fish have been caught in small, unnamed waters, including private ponds, golf course ponds, retention ponds, and undisclosed public lakes.

“Those types of waters aren’t typically managed,” Pouder said. “But that suggests we might look into that for the future.”

Also worthy of note is that TrophyCatch has given lie to the notion that anglers must use shiners to catch big bass in Florida. More 60 percent of entries were caught on artificials.

More of that kind of helpful information will be available to anglers soon, as FWC develops a more in-depth website for TrophyCatch, which will allow each entrant to have his or her own page.

In Texas, meanwhile, managers continue to look for new ways to improve the state’s trophy bass fisheries through ShareLunker, a program built around stocking Florida strain largemouths. Before the Lonestar State introduced the larger variety of black bass, its state record of 13.5 remained unchallenged for 37 years. Since stocking began in the 1970s, the record has been broken six times, and three since ShareLunker began in 1986.

Current Texas record is 18.2, larger even than the biggest bass documented in Florida at 17.27.

Courtesy of ShareLunker, Florida bass now swim in 62 Texas impoundments. They are spawned in hatcheries from the ShareLunker entries of 13 pounds or more that Texas fishermen donate to the program.Incredibly, 51 percent of ShareLunker entries are pure Florida bass, with the rest being hybrids. Yet sampling reveals that Florida bass typically make up only about 7 percent of a fishery’s bass population.

“A real value of the program has been that it has convinced anglers that they do not have to kill their catch to get a trophy,” said Allen Forshage, director of the Texas Freshwater Fisheries Center.

In exchange for donating their fish, anglers are given replica mounts.

Right now, focus is on DNA and how tracking it might help produce a fish that could rival the world record of 22-4. While breeding ShareLunker entries to male ShareLunker offspring, biologists have developed a technique to identify both parents in future trophy bass.

Tagging already has revealed that sometimes entries are caught more than once. In fact, one was caught three times.

“I was a pessimist when we first started this program,” Forshage said. “We had no idea that one day we’d have 62 lakes producing these lunker fish.”

(This column appeared originally in B.A.S.S. Times.)