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Entries in grass carp (23)


National Policy Needed to Help Stop Spread of Grass Carp

This grass carp was illegally stocked in a lake where it wasn't needed, and the health of the fishery has suffered as a consequence. Photo by Robert Montgomery

Although grass carp have been found in every one of the Great Lakes except Superior, resource managers don’t believe that the exotic fish have established a self-sustaining population.

But the Mississippi Interstate Resource Association (MICRA) recently warned that “state grass carp regulations are varied and inconsistent, and a national policy strategy is needed to effectively minimize the risks of additional fertile and sterile grass carp introductions into the Great Lakes.”

MICRA reached that conclusion as result of a study funded by the U.S. Fish and Wildlife Service (FWS) to look at grass carp use, production, and regulations. It also made recommendations to help minimize risk not only to the Great Lakes, but other waters not yet infested by unintentional introductions of this aquatic invader.

Those recommendations include the following:

  • Production, shipment, stocking, import, and export of diploid (fertile) grass carp should be prohibited except by licensed facilities.
  • States that allow production of triploid (sterile) grass should develop a set of minimum standards, permit requirements, and recordkeeping for diploid broodstock.
  • States that allow importation of triploid carp should adopt consistent regulations that allow only FWS-certified fish.  Also, increase random inspections and enforcement of regulations in these states.
  • FWS should work with states, producers, and other partners to develop testing procedures for quality controls and law enforcement in support of random inspections.

Grass carp, a species of Asian carp, were first imported into the U.S. in 1963 as a tool to manage nuisance aquatic vegetation, including exotic hydrilla, in ponds and impoundments. But flooding allowed many to escape into rivers and streams and, by 1970, they were reported in the Mississippi River basin.


Grass Carp Gobble Up Lake Austin's Grass, Reputation


Gut contents of a Lake Austin grass carp. Photo by Brent BellingerAs grass carp gobbled up all the aquatic vegetation in Texas’ Lake Austin, they also obliterated the reservoir’s reputation as one of the nation’s top bass fisheries.

“When the grass was around 400 to 500 acres for a couple of years, the bass fishing really took off,” said John Ward, marketing director of the Texas Tournament Zone (TTZ). “The fish were fat and healthy. We had a great sunfish and crawfish population, and plenty of ambush spots for the big girls to grab them.

“Now sunfish and crawfish numbers are significantly down. You see more schools of bass chasing shad balls instead. The worst feeling is when you finally get a big girl, and it’s a 10-pound head with a 5-pound body. They just can’t eat like they used to.”

Understandably frustrated anglers blame mismanagement and/or the powerful influence of lakefront property owners who don’t like hydrilla. For example, one said that Texas Parks and Wildlife (TPW) “grossly overstocked this lake with grass carp.”

He continued, “In less than a year, we have seen complete devastation of this great fishery. The grass is 100 percent gone. Reeds that used to line the lake in places have been uprooted and chewed off at the stalks.”

But the reality is more complex and less malevolent. What happened was the inevitable result of an unavoidable set of circumstances involving weather, two exotic species, and reservoir management priorities.

“This trophy fishery was maintained along with grass carp stockings for many years,” said Texas biologist Marcos De Jesus.

“This extreme drought scenario has thrown a monkey wrench in our management efforts, but we are learning from this experience to avoid a similar outcome in the future.”

Managed by the Lower Colorado River Authority, Austin is a 1,599-acre riverine impoundment on the Colorado River. During normal times, cool discharges into the flow-through fishery combine with a sustained population of grass carp to keep hydrilla in check. Also, less problematic Eurasian watermilfoil thrives, serving as another control. But starting in 2011, drought diminished flow, allowing water to warm and igniting an unprecedented growth spurt in hydrilla. By spring 2013, hydrilla covered nearly a third of the reservoir.

If not kept in check, hydrilla can block flow, pushing water onto highly developed shorelines, De Jesus explained. Consequently, more dramatic control was required, and it could only be done with grass carp. Herbicides are not an option for Austin, which also serves as a municipal water supply.

A stocking of 9,000 carp in May 2013 supplemented 17,000 introduced in 2012, providing 55.5 fish per acre of hydrilla. And, as anglers watched in dismay, the fish quickly gobbled up all of the lake’s aquatic vegetation, except for shoreline plants protected by cages.

“Now we are in a situation where the carp are keeping everything at bay,” said the biologist. “Every time it’s been down to zero, though, it bounces back. We’re now looking at creating habitat (brushpiles) and doing some carp removal.

“Fishing always has been our priority,” he continued, pointing out that electrofishing revealed bass still are plentiful.

“But they’re now suspended in deep water, and people will have to transition to other fishing styles. We were all spoiled. We all loved that lake, and this change was not one that we wanted.”

Brushpiles will help, said Ward, who added that TTZ will help organizes anglers to assist. “But nothing can replace natural habitat. As long as you have 20,000-plus grass carp in a 1,600-acre lake, grass will not grow.

“It’s the aquatic vegetation and the healthy habitat it provides that brings out the potential for big bass in Lake Austin.”

(This article was published originally in B.A.S.S. Times.)


Battling --- And Besting --- The Big One

Once again the huge fish bulled for deeper water. And once again I pumped and reeled to regain line.

If frogs croaked or birds sang on this cool evening in early fall, I didn’t hear them. The only sounds that I remember are the “Whap! Whap! Whap!” of the monster’s broad tail as it slapped the surface of the still, shallow water, and the “Zsst! Zsst! Zsst!” of the drag on my spinning reel as it protected my 12-pound line from breaking.

The fight lasted 15 minutes at least, probably more. I knew that I had to weaken the grass carp to have any chance of wrestling it ashore, but I also realized how perilous our connection, with light line and small hook. That’s why I eased off on the drag each time I brought it close to my dock. At close range, one hard headshake from a fish that size, even a tired one, would part the line.

Finally, I judged it ready to be landed, knelt on one knee, held the rod with my right hand and scooped with my left. Only my net was far too small to get much more than its head in it. And as I belatedly realized that, a barb on the little treble snagged in the mesh. Now, a foot or so below the side of the dock,  I had the huge carp half in and half out of the net, and there was no way I could lift the fish with one hand, even if it all did fit.

Suddenly, the once tired fish became manic, thrashing wildly, and I all but acknowledged that I had lost the fight.  I was certain that the line would break as the carp jerked against the resistance of the hook embedded in the net.

Hook on right is the one that I removed from carp and net.

But I pushed the net as deep as I could, and the fish bolted farther into it instead of away from it. Nearly simultaneously, I dropped the rod, grabbed the handle with both hands and heaved.

And finally there it was, a 40-pound-plus grass carp half in and half out of the net on my dock. Somehow, someway, I had managed to land the beast with a net that likely was better suited for butterflies than fish of this size.

I know that it was 40 plus because it was far heavier than my previous best, which had bottomed out a 30-pound scale.

During the nine years that I’ve lived on this 10-acre semi-private lake, I’ve caught about 20 of the illegally stocked grass carp, which have suppressed the bass, bluegill, and catfish populations and degraded the water quality.

Aquatic vegetation never has been a problem in this normally clear, spring-fed lake, but ignorant property owners stocked the carp, thinking that they were filter feeders that would improve the water quality. One of them actually told me that.  In truth, grass carp are the equivalent of aquatic cows, adding to the nutrient load as they grow to massive size, and contributing to algae blooms as they stir up the bottom.

But they are fun to catch, fighting a lot like big redfish, and I’ve perfected the technique --- at least for my little lake. I fish only for the carp that I can see. Once I’ve spotted one, I toss a bread ball under a bobber in front of it. Sometimes, I have to increase the depth of the bait to get the fish to take. Last night, I had to do that three times.

When I go back out there this evening to look for the three others that saw with the one that I caught, I should have it at the proper depth on the first try.

And I will have a larger net.

To read about the 30-pound carp that I caught and learn more about why grass carp generally are bad news for sport fisheries, go here. I'm not suggesting that grass carp can't be used to manage aquatic vegetation in certain circumstances, but they're tools that only fisheries biologists should consider.


How About Hippos?

If you think that we’ve made a mess of our lands and waters through intentional and unintentional import of exotic plants and animals, you are correct. For example, we now spend billions of dollars annually to control and mitigate the damage done by just four recently introduced species: bighead carp, silver carp, quagga mussel, and zebra mussel.

And in attempts to minimize problems, the government often has made them worse. During the 1940s, the state of Louisiana touted the South American nutria as a way to control water hyacinth, a fast-growing exotic that was crowding out native vegetation in wetlands. Today, the nutria is eating away those same wetlands, contributing to saltwater intrusion and coastal erosion.

In the early 1960s, the states of Alabama and Arkansas allowed import of grass carp to control aquatic vegetation in aquaculture ponds. By 1970, escapees had established populations in the Missouri and Mississippi Rivers. Today, these troublesome grazers are established in at least nine states and have been sighted in more than 40. Ask just about any bass angler, and he will tell you that the grass carp is public enemy No. 1.

And speaking of carp, we have the federal government to thank for one of the worst management decisions ever in regard to our fisheries. In 1877, the U.S. Commission of Fish and Fisheries began intensively cultivating and stocking common carp. In fairness, it was prompted to do so both by public pressure and by overharvest of native fish stocks. By the turn of the century, however, it already was regarded as a nuisance.

“Moreover, their rapid spread appeared to threaten both water quality and native species, as commissioners nationwide noted a deterioration of formerly clear and fertile lakes and waterways upon the arrival of carp,” says the National Park Service.

But you don’t know the half of it. Actually, things could be worse. Much worse. Instead of nutria eating away those Louisiana wetlands, we could have hippos. And who’s to say that these massive “water horses” which can weigh up to 4 tons and eat up to 100 pounds of vegetation a day, wouldn’t have spread east, west, and north?

They are “relatively tolerant of cold conditions,” says the Glen Oak Zoo, which also points out that “many individuals live to 40 years.”

Oh yeah, they also are generally believed to have killed more people in their native Africa than another animal, including lions and crocodiles.

All things considered, I’ll take the nutria, thank you. It tops out at about 12 pounds and is not as likely to charge me at the launch ramp.

But in 1910, Frederick Russell Burnham, a famed American scout and world adventurer, proposed replacing our nation’s depleted wildlife population --- we had hunted deer, turkey, and buffalo nearly to extinction --- with animals that he had encountered in southern Africa.

His proposal lined up nicely with the search for a solution to the growing problem of water hyacinths in Louisiana waters, as well as America’s need for more meat. Writing about this little known piece of American history, Jon Mooallem in American Hippopotamus, says that Rep. of Robert Foligny of New Iberia “liked to plug up problems with big solutions.”

Thus, Foligny introduced H.R. 23261, also known as the “Hippo Bill,” to “appropriate $250,000 for the importation of useful new animals into the United States.” The Washington Post assured readers that they would see shipments of hippos within a few years.

Fortunately for all us, a boatload of hippos never docked in New Orleans. But it wasn’t because of the unexpected discovery of good judgment in Congress. Rather, one representative said that the beasts should not be introduced because unscrupulous hunters would sneak onto the farms and hunt them for trophies.

Yeah, that’s the reason not to import aggressive animals that boast 20-inch teeth and can run at speeds of more than 20 miles per hour.

What turned the tide, though, was that the Department of Agriculture decided to transform swamps and other undeveloped areas into agricultural land to grow more beef cattle.

Thank goodness. Otherwise, we might we watching “Hippo Die-Nasty” instead of “Duck Dynasty” on television.

(This column was published originally in B.A.S.S. Times.)


Third Carp Species Also Threatens Great Lakes

Activist Angler caught this 30-pound-plus grass carp in a lake that has been damaged by illegal stocking of this exotic species. Photo by Robert Montgomery.

When people talk about Asian carp threatening the Great Lakes and its fisheries, they typically are referring to bighead and silver.

But a third species also potentially could damage this vast freshwater ecosystem if it becomes established in substantial numbers.

The grass carp was introduced into U.S. waters about 50 years ago, with the intent of using it to manage invasive aquatic vegetation. It has done its job--- and then some. Too often it has obliterated all vegetation in a water body, including beneficial native plants.

Additionally, it has escaped and established wild populations, as did the bighead and silver. Today the grass carp is believed to be in at least 45 states.

And now this invader poses danger for the Great Lakes.

Researchers recently documented that grass carp have spawned in the Great Lakes, specifically in Ohio’s Sandusky River, a tributary of Lake Erie. They also point out that 45 of them were caught in the Great Lakes between 2007-2012. That’s not a lot, but it’s 45 too many, especially since about half of those were capable of reproducing, meaning that an established population might already exist.

That does not bode well for bass, pike, and other inshore species that thrive in and around aquatic vegetation.

Read more here.

By the way, I have personal experience with grass carp. Years ago, ignorant property owners illegally stocked grass carp in the little lake behind my house because, they said, “they filter the water and improve the water quality.”  They did so, even though the lake contained little, if any, aquatic vegetation.

Somehow, the carp have survived and today some of them weigh 30 pounds or more. They’re the equivalent of big aquatic cows, degrading water quality, not improving it, as their wastes feed alga blooms during summer.

Also, hundreds of pounds of carp prevent growth of hundreds of pounds of bass, bluegill, and catfish. Like a farm field, a lake can sustain just so much biomass.