Imagine buying 3-inch fish for an aquarium, with no idea that they have the potential to reach the size in the photo above. That happens time after time all over the U.S. when hobbyists buy pacu, which resemble their smaller piranha cousins. They have impressive dentures of their own, but their teeth are flatter and used mostly for cracking nuts and seeds.
And every summer, the consequences of those purchases play out, as anglers report catching pacu released into public waters by irresponsible aquarium owners. For example, this year, two were caught in Michigan's Lake St. Clair and another in the Port Huron area.
Standard response from both anglers and the public in general when this happens is "Well, they wouldn't have survived the winter anyway." In most cases, this is true.
But not always, as I reveal below in a story that I first wrote for B.A.S.S. Times and Activist Angler three years ago.
And one of these days, pacu or piranha, maybe both, just might find welcoming waters where they too can survive in a climate far too cold for them under normal conditions. Those areas might be springs or perhaps warm-water discharges from power plants.
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What resource managers long have feared would happen because of irresponsible fish hobbyists has become reality: An exotic species has established itself in a waterway far north of where it should be able to survive.
Earlier this summer, biologists confirmed that the Jack Dempsey, a South American cichlid related to the peacock bass, is reproducing in South Dakota’s Fall River.
How it that possible?
“The hot springs in the river makes it perfect for cichlids,” said Mike Smith, aquatic nuisance species coordinator for South Dakota Game, Fish and Parks. “We first found a Jack Dempsey there in 2009. Then, two weeks ago, we found multiple-year classes.
“And there’s no way that the fish could have gotten there except aquarium release.”
Water nearest the springs stays at about 70 degrees year around, which allows the exotic fish to survive brutal South Dakota winters.
In this case, the Jack Dempsey’s impact on native species likely will be minimal. Few other predators live in the shallow water, and forage species gobbled up by the aggressive cichlid can be replenished from populations outside the range of the hot spring’s influence.
But the discovery is significant because it confirms that exotics can use thermal refuges provided by springs or warm-water releases from power plants to survive in cold climates.
Could the piranha be the next exotic fish to become established? Or its much larger cousin, the pacu? Every summer, media across the country report catches of both fish in ponds, lakes, and reservoirs. For example, a pacu was caught in Illinois’ Lake Lou Yaeger in June. And at Missouri’s Lake of the Ozarks, piranha captures have been reported several times since 2007.
Fish hobbyists also have contributed to troublesome infestations of plants such as Brazilian elodea, parrot feather, yellow floating heart, and even hydrilla.
“At a lot of our lakes, people just dump their aquariums to get rid of whatever they don’t want anymore,” said Tim Banek, invasive species coordinator for the Missouri Department of Conservation.
Bill Frazier, conservation director for the North Carolina B.A.S.S. Federation Nation, also has seen evidence of aquarium dumping while serving as monitor of water quality for the city of High Point. He thinks the time is long past for directing blame primarily at anglers, especially bass fishermen.
Much of the problem, he insists, lies squarely with aquarium hobbyists and the pet industry that supplies them, as well as with nurseries that sell exotic aquatic plants.
“I haven’t seen a single trace of any invasive (plant) at the ramps, transferred by boat in 28 years,” he said.
“I know the overall perception is that weeds can be spread by anyone with a watercraft. I am not denying this pathway,” Frazier continued. “I just do not believe it as significant as everyone would have you believe.”
The North Carolina water expert has found parrot feather upstream of a submerged roadbed, where boats can’t go. He has discovered water hyacinth just downstream from a farmer’s market that featured the exotic in a water fountain. And he has seen a discarded aquarium underneath a parrot feather infestation, where the shoreline borders a large apartment complex.
“Some time later, a bank fisherman caught a skillet-sized pacu there,” he added.
And while anglers and the fishing industry pay license fees and excise taxes to finance management of aquatic resources degraded by aquatic invaders, these special interests are allowed to escape responsibility for the damage they do.
“This is what we need to be attacking and taxing,” he said.
I caught this medium-sized peacock bass on Venezuela's Lake Guri a few years back. That same day, I battled a giant that I write about in the essay "Legendary Fish" in Why We Fish. Here's an excerpt:
A frayed piece of leader owns a place of honor at my desk. It was left to me by a “legendary fish.”
That’s my own term so I’m not surprised if you haven’t heard it before. For me, “legendary fish” is one rung up the ladder from “big,” “trophy,” and even “fish of a lifetime.”
Most don't know one carp from another. All are exotic.The photo above is a 30-pound-plus grass carp illegally stocked in a small lake.
Common carp have been in this country for so long (more than a century) that many think they are native. They are not. They were imported by the federal government. Rooting around on the bottom, they have destroyed and degraded many fisheries.
Fish farms in the South and Mid-South imported Asian carp (bighead and silver), and they escaped into rivers, spreading throughout much of the country. Through filter feeding, they gobble up forage needed by many native species, including juvenile sport species.
Grass carp were imported to eat problematic aquatic plants, including hydrilla and Eurasian watermilfoil, also exotic species. Often they were overstocked. Sometimes. they were stocked where they were not needed. Often they were stocked illegally. And they too have escaped and spread.
To add to the confusion, Canadian media and fisheries officials frequently refer to grass carp as Asian carp.
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Although silver and bighead are the Asian carp of most concern these days for the Great Lakes and its tributaries, disturbing discoveries have been made lately regarding a third--- the grass carp.
First, a graduate student at the University of Toledo found eggs in the Sandusky River, which flows into Lake Erie. That confirms the existence of a reproducing population of this fast-growing species, which doesn't compete with native fish, but does obliterate beneficial aquatic vegetation.
Additionally, Canadian commercial fishermen recently netted a grass carp weighing more than 60 pounds from the St. Lawrence River, far above Lake Ontario.
Anthony Ricciardi, a biology professor at McGill University, doesn't think that the river has a reproducing population, but suspects that others are in the St. Lawrence as well.
"We actually thought the Asian carp was confined," added Quebec biologist Michel Legault. "But we know that in recent years the grass carp has been found in a small section of Lake Erie. And last summer, nine grass carp were caught in the Toronto area. This is not good news."
On the Sandusky, meanwhile Toledo researchers intend to learn more about the grass carp spawning there, in hopes of finding a way to minimize it.
"Given the similarities in reproductive strategies, this ongoing research on grass carp spawning may help us minimize the risk of bighead carp and silver carp from establishing a foothold in the Great Lakes, said Patrick Kocovsky, a fisheries biologist with the U.S. Geological Survey. "What we learn here also might apply to potential control strategies in tributaries to the Mississippi River.
Today, most grass carp used to control invasive aquatic plants are triploid, meaning they can't reproduce. But fertile grass carp are believed to have first escaped from an aquaculture facility in Arkansas back in the 1960s. They since have migrated throughout the Mississippi River drainage, as well as spread through authorized, illegal, and accidental introductions to 45 of the 50 states.
These are but a few of the secrets in "The Bite" from Better Bass Fishing: Secrets From the Headwaters by a Bassmaster Senior Writer. Also, here's a link to the book at Barnes & Noble.
Secret: Bass don’t see artificial baits the same way that we do. That new shad-shaped crankbait that you bought might look so lifelike that you expect it to flop off the table. But what makes it lifelike--- and attractive--- to bass is how it moves through the water. Yes, a realistic appearance helps, but good action that imitates an injured or fleeing baitfish probably is more important. That’s why spinnerbaits, which don’t resemble any kind of living creature when motionless, are such effective bass catchers.
Secret: With soft plastics, however, sometimes action isn’t important at all. Rather the fish need time to approach and examine. On several occasions, I’ve spent a minute or two picking out a backlash and then found a bass on the end of my line. Others have told me of similar experiences. This tells me that, too often, we fish too quickly with soft plastics.
Secret: In fact, lure designer and tournament angler Troy Gibson recommends letting a soft plastic sit for 120 seconds after you cast it.
“I will find the fish by power fishing with spinnerbaits and crankbaits,” he says. “And sometimes this is all I need to fill the livewell.
“But when I come across an area that looks as if it will produce 3- to 5-pound fish, then I will slow down with a fluke or worm and be very patient. I will present my lure to a tree, bush, or creek channel and let the bait sit still for at least 120 seconds.
“The bass is just like an old cat that can not leave well enough alone and will pick up, move, eat, or play with the fluke or sinking worm. It can’t help itself, for that is its nature. Understanding that, along with patience, will make you a much better fisherman.
“By doing this, I am more likely to cull the first five fish with larger fish. To me, the smaller fish that I caught by power fishing are the locator fish for areas that are holding the larger fish.”
Secret: To obtain the most up-to-date information on bass biology and behavior, as well as new strategies for catching them, read Bassmaster Magazine and BASS Times. These are the most authoritative sources on bass fishing in the world. Many of today’s young pros say that they grew up reading Bassmaster and the knowledge they gained from the magazine was critical to their success.
Check out all my books at Amazon.