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Entries in Asian carp (144)

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.

Sunday
Apr192015

Largemouth Bass Chow Down on Bighead Carp in Lab Tests

Bighead carp grow large. But bass eat them when they're smalll and more vulnerable

“Asian carp” actually refers to two species of exotic fish, not one. As they spread throughout the nation’s rivers, both pose threats to native fisheries.

As it turns out, though, there seems to be a big difference in their vulnerability to predation. That’s bad news for bighead carp, which grow larger, feed more exclusively on zooplankton, and are less abundant. And good news for the smaller silver carp, which have become infamous for endangering boaters with their leaping antics.

Researchers at the Illinois Natural History Museum and University of Illinois put small samples of both into experimental pools, along with bluegill, gizzard shad, and golden shiners. Largemouth bass in those pools ate more bighead carp than any other species, including silver carp. Scientists hypothesized that this may mean that young silver carp are more “street smart” than their bighead cousins.

While it’s good to know that bass can and likely do eat these invaders, especially bighead carp, whether this predation will help control them remains to be seen.

“Although new research is confirming that native fish can and do consume Asian carp, this not mean that all is well,” cautioned the Michigan State University Extension (MSUE). “In the LaGrange Reach of the Illinois River, at least seven native fish are preying on Asian carp. Even so, this reach has one of the highest densities of silver carp recorded anywhere in the world.

“Native plankton-eating fish like gizzard shad and bigmouth buffalo have declined and the long-term effects on gamefish are still uncertain.”

In 2008, biologists estimated more than 5,000 silver carp per mile in that nearly 80-mile stretch of the river, with a biomass of 705 metric tons.

“In the Great Lakes, we already know that native fish are adapting to non-prey items like quagga mussels and round gobies,” MSUE continued. “We also know that predation has not been enough to eliminate these species or prevent their negative effects. The same is likely true for Asian carp.”

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

Friday
Mar272015

A Good Use for Asian Carp

Burr Edde (left) and stepson Lucas Miller with record blue catfish.

Burr Edde III of Malta Bend became Missouri’s most recent record-breaking angler when he landed a giant blue catfish on a stretch of the Missouri River in Saline County using a trotline. The new “alternative method” record blue catfish caught by Edde on March 21 weighed 120 pounds, 8 ounces, with a length of 55 and 1/8 inches and a girth of 45 inches.

Edde used cut Asian carp as bait.

The giant broke the previous alternative-method state-record blue catfish of 117 pounds caught in 1964 on the Osage River.

Missouri Department of Conservation (MDC) staff verified the record-weight fish on March 25 using a certified scale at Bass Pro corporate headquarters in Springfield. The fish was preserved on ice for official weighing.

“Oh my goodness! That’s a big fish,” Edde recalled when he first saw the giant. “How am I going to get this one into the boat?! It was definitely an experience of a lifetime to catch one that big. I was blessed. And there are still lots of them out there!”

The longtime angler said he would have liked to release the record fish or donate it to the fish tanks at Bass Pro, but it didn’t survive long enough. “It’s too big to actually have mounted, but I’m getting a replica made.”

 

Wednesday
Feb182015

How About a Nice, Cold Beer Brewed With Zebra Mussel Shells?

Slowly but surely, the public is awakening to the value of Asian carp as food.

And what possibly could go better with a carpburger than mussel beer?

More specifically, a Milfoil Lakehouse Saison Ale, brewed with zebra mussel shells and Eurasian watermilfoil by Excelsior Brewing Co. on Lake Minnetonka. The beer with the “exotic, invasive flavor” is promoted as a way to heighten public awareness about the problems caused by exotic species.

This past fall, Grumpy’s Limited Action Beer Fest challenged breweries to develop beer using only Minnesota ingredients, and Excelsior decided it wanted to push the envelope. It blended Minnesota wild rice, Minnetonka honey, and local hops with a small dollop of aquatic hitchhikers.

“We thought, ‘We’re going to take this to the extreme,’” said Paul Awad, a spokesman for the brewery. “It ended up being a really great beer.”

He explained that only tiny amounts of milfoil and mussel shells were used, and filtering prevents beer drinkers from finding a trace of the ingredients in their glasses. “Neither of them adds a lot of flavor. It’s more the novelty of it,” he said, adding that the brew tastes like many Saisons, with fruity, spicy overtones.

Ryan Anderson from MNbeer.com wasn’t particularly surprised by the mussel/milfoil beer. “There are some breweries out there trying some crazy things,” he said.

For example, seaweed as an added ingredient is becoming more common, while other micro breweries are trying things like fish bladders and oyster shells.

“It’s definitely a kind of interesting thing,” he said of the Excelsior beer. “But stranger things have happened.”

Meanwhile, a spokesperson for the Department of Natural Resources said the exotic brew “sounds really unusual.”

Before this latest offering, Excelsior already created beers that honored its lakeside location, including Big Island Blond Ale. Additionally, 1 percent of its profits support the popular fishery via donations to organizations such as the Freshwater Society.

Meanwhile, in the Cafeteria . . . 

The University of Missouri is testing recipes and gathering reactions as it considers adding the invasive Asian carp to the menu in its dining halls.

About 40 students tried different recipes using the fish during recent taste tests at the Sabai Culinary Development Kitchen on the Missouri campus, and their reactions will help the culinary staff decide whether to serve the fish.