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A carp by any other name doesn't spawn the same: catching the facts on the bigheads in Lake Byron
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The jarring carp "news" in the state fishing handbook

Call this the story of Byron and the Bigheads.


Which would make a pretty good name for a rock band, although Bighead Todd and the Monsters might object. People get so touchy.


But in this case, and with “bigheads” in lower case, it’s about the bighead carp in Lake Byron and their place in the overall battle against invasive aquatic species in South Dakota.


Just to be clear: Invasive aquatic species do not rock!


I didn’t know there were bighead carp in Byron until this week.  I happened to be leafing through the 2019 South Dakota Fishing Handbook on other business and paused on the "aquatic invasive species" page just long enough to get a little nervous.


OK, a lot nervous.


What I saw there had me suddenly worrying about the bigheads, about Lake Byron and about the overall integrity of our lakes and streams. I’m not quite so worried now, after making some calls and learning some things. It’s funny how that works, isn’t it?


Knowledge is a useful thing. I wish there were more of it on social media and in political rhetoric, and less hysterical exaggeration and outright fiction. But that’s another story of bigheads, for another time.


For now, let’s stick to Byron and the bigheads and the reasons that I’m not quite so worried as I was when I first saw the unsettling “news” — which is actually several years old — on page 40 of the fishing handbook.


First, though, a bit of background on Lake Byron, which I’ve never actually fished, at least not that I can remember. In fact, I’ve only even seen it in person a handful of times. And then, no offense, my reaction was something short of breathless awe.


Before bigheads, Lake Byron was known for Big Toads


As it turns out, though, the lake was associated with something “big” long before the bighead carp arrived. According to way-back records compiled through the U.S. Writers Program of the Work Projects Administration, indigenous people called the body of water Big Toad Lake because of the toad-like shapes of trees on its shores.


The lake became Byron over time and non-indigenous influence as a way of honoring Byron Pay, brother of a newspaperman in Huron. He apparently camped at the lake and carved his initials into one of the trees, perhaps one that looked a bit like a toad.


Interesting stuff, I think. But then I think old newspapermen and toads and carp and lakes are interesting. So I’m interested in Byron, even though it’s a fairly humble patch of prairie water covering about 1,800 acres of Beadle County, 15 miles or so north and east of Huron.


 Like a lot of prairie lakes, Byron’s kind of plain. It’s kind of murky. And it’s kind of shallow. That makes it prone to periodic winter kill. And that means the state Game, Fish & Parks Department crews gets to know the lake through fish surveys and stocking operations.


During good years, Byron has spurts of decent walleye fishing, along with some perch and crappie action. It’s mostly rough fish, though, especially bullheads and carp and  the occasional big-mouthed buffalo fish, a native species that commercial fisherman tend to prefer — one that I know, from experience, tastes fine coming out of a deep-fat fryer.


And then there’s the bighead carp, a decidedly non-native species listed along with silver carp — which can leap from the water and become silver missiles when aroused by the racket of a speeding motorboat — in a lake that seems pretty isolated from other water bodies.


That isolation part is what really worried me, of course. I knew about the bigheads and other invaders in the some of our rivers. But that made sense. River fish get around in flowing systems, sometimes for hundreds of miles. How, however, did the bigheads and silvers get to Byron? And if they got to Byron, where couldn’t they get?




Beyond Byron, the battle against invasive aquatic species


I don’t have any great personal investment in Lake Byron, beyond knowing that it has value in its ecosystem and is loved and used by locals in a way I’m sure I’d admire. I do have a personal investment in lakes, and in fisheries, and in trying to keep lakes and fisheries as unencumbered by invasive species as possible.


That’s’ why I paused at the aquatic-invasive-species page to check the status of the statewide battle against them. There I found more than 30 listed lakes, rivers or river stretches in the state infested to one degree or another with one or more of 16 different invasive species, plants or animals.


Bighead carp are a worrisome invasive species. So are silver carp. So are their slippery cousins the grass carp. All three are lumped under the “Asian carp"category, and are different than the common carp. Still, it’s easy to assume the Asians could be just as big a problem as the common carp.


At least, that’s what I assumed until I made a call (It’s what reporters do) and John Lott answered.


Lott is the aquatic resources chief for GF&P in Pierre. His predecessors in that position were called fisheries chiefs, and I covered a couple of them, for a lot of years. But Lott is no baby in the business, either. He has been a fisheries biologist for GF&P since the early 1990s and aquatic-resources chief since 2008. That means he has answered more dumb questions, and some that weren’t quite so dumb, from me than he might care to count.



Lott tends to have a calming demeanor, which is useful when dealing with irate anglers and overwrought reporters. Responding to my slightly-less-than-hysterical concern about Byron and the bigheads, he said that while bighead and silver carp cause problems, they can’t match common-carp problems.


There’s a big, meaningful difference in spawning. Common carp broadcast a quarter million eggs or more per spawning female over aquatic vegetation in shallow bays and backwaters, just about anywhere and everywhere, it seems.


It’s a much different process for the bigheads and silvers. Different and less successful, at least in most prairie water systems.


“They’re not like regular carp,” Lott said. “The bigheads and silvers need a number of miles of flowing water to reproduce. Their eggs are a lot like paddlefish eggs, they need to drift in the current and then hatch out.”


If the eggs don’t keep drifting, they don’t keep living. So bigheads and silvers need to make an upstream migration into flowing water to find suitable spawning areas and flows. The speculation is that some of them were moving upstream during heavy flows some years back when they found their way to Byron, which is on Foster Creek and drains into the James River.


Rain and runoff can offer a route to new lakes


eSo, there’s the route, under the right conditions. And they apparently they were right some years back. You could speculate about them being right again this year, given the rain and runoff. But I don't want to get worked up right now.


Once the bigheads were in Byron a few years back  they didn’t have much to do besides swim around and suck on stuff. Tiny stuff. Important stuff. They are filter feeders, meaning they spend most of their time straining out zooplankton and phytoplankton, the tiny animals and plants that make up the foundation of a healthy aquatic food chain.


But without reliably flowing rivers and stream to wander up toward spawning areas, they almost certainly haven’t reproduced in Byron, and probably can’t. At least, that’s the assumption and hope, based on experience here and elsewhere.


“Everything we know about the biology, which isn’t a lot since they’re fairly recent, says they’ve got to have large, slow-moving rivers in order to reproduce successfully,” says Todd St. Sauver, area fisheries supervisor for GF&P in Sioux Falls. “They’ve been in northwest Iowa lakes for several years now and to my knowledge they have not seen any reproduction there. I’ve heard no reports of anywhere around North America where they’re gotten into a lake and exploded in population like we’ve seen with common carp.”


Which is a good thing, for lakes. Because with lots of human help, common carp have spread to and thrive in most of the significant freshwater ecosystems on earth. Native to Europe and Asia, common carp have become a head-scratching problem here, with insufficient solutions.


Introduced to the United States in the early to mid-1800s primarily as a food fish, common carp went far beyond domestic pond life and the dinner table. They are hardy, resilient, reproductive machines in many types of lakes and streams, and they sometimes spawn more than once a year — just to rub it in, I think.


Bigheads and silvers are relative newcomers, having been brought to the U.S. a few decades back. And they are positively manageable compared to common carp, at least in prairie lakes.


“I’d say the potential impact of the silvers and bigheads, from an ecological-system perspective, are much less detrimental than common carp,” Lott said. “I’m not saying they’re good, but they’re not like common carp.”


Even the Asian carp varieties can do plenty of damage


Which doesn’t mean you like having these invasive carp spread out, as they’re doing when stream-flow situations are favorable. Because in the right riverine conditions they can dominate and decimate a food chain needed by less-numerous, less-aggressive native-fish species.


And the silvers? Well, they can smack you in the face, literally, in the right situations. 


“There’s no doubt that when these bigheaded carp are abundant, as they are some of the eastern rivers, and also the silver carp, especially when jumping all over, they can be problematic,” St. Sauver said. “But based on all the information we have available so far, we’re cautiously optimistic that they won’t have a big impact on lakes, even if they get into them.”


Which doesn’t mean GF&P wants them to spread beyond their locations now, which is in stretches of the major river systems in eastern South Dakota  below large dams or falls that block further upstream migration.


Bigheads and silvers and their cousins the grass carp —  an especially popular aquaculture fish that also needs running water to spawn — have been confirmed in South Dakota in the James River, the Vermillion River below East Lake Vermillion, the Missouri River below Gavins Point Dam and the Big Sioux River below Falls Park in Sioux Falls.


So far, Byron is the only prairie lake in the state known to have bigheads and silvers.  And it’s unclear how many are there. There were only a few fish detected several years ago by commercial fishermen during netting operations for carp and bigmouth buffalo fish on the lake, St. Sauver said.


In November of 2012, a commercial fisherman found two bigheads and one silver in his nets along with the targeted fish. In October of 2015, another commercial fisherman on Byron found a single bighead.


“So the numbers we were dealing worth weren’t large at all. And nobody else has ever reported one. We  (GF&P staffers) have never seen one there,” St. Sauver said. “I did not get picture confirmation from the commercial fisherman. But knowing how experienced they are I have no reason to doubt them.”’


So, the bigheads, and maybe the silvers, are probably there, just not in great numbers. And while you never say never in the fish business, St. Sauver comes pretty close when asked about the idea of bigheads, silvers and grass carp taking over South Dakota lakes.


“I’m always cautious in saying that, because Mother Nature has a way of adapting her species to conditions,” he said. “But I’m cautiously optimistic they won’t have a big impact on our lakes, even if they get into some of them.”


That was a relief to me. And now that I’m more relaxed I can resume leafing through the fishing handbook, starting again on the aquatic-invasive-species page.


But wait a minute. It says there are European rudd in Lake Madison!


I gotta make another call.