Conservation: Not All Invasive Species Become Homewreckers

Capt. Bob Wetherald has been guiding hunters and anglers on the Chesapeake Bay and Potomac River for 16 years, but until five years ago he had never guided bowfishers. His clients were interested in targeting northern snakeheads, predatory fish native to China and Korea that had started appearing in increasing numbers in the grassy flats of the Potomac and its tributaries, so Wetherald rigged up a boat with lights and shooting platforms.

"When snakeheads first started showing up, I was like a lot of people who heard only about how detrimental they were to our sport fisheries," says Wetherald, who owns and operates Mid River Guide Service (midriverguideservice.com). "We'd see them occasionally when we were targeting bass, and I was like, 'kill 'em all,' and with extreme prejudice."

Maryland's Department of Natural Resources has taken a hard line on the invasive fish, which were probably brought to the United States in the aquarium trade. The sinuous fish can live out of the water for hours, breathing air instead of extracting oxygen through their gills. They have no natural predators in their adopted waters. They are highly adaptable to a wide range of habitats. And they are so aggressive and reproductively successful that they can decimate native and managed sport species if their populations are unchecked.

Maryland, and many of its neighboring states, has a made it illegal to possess, import or transport live northern snakeheads, and even if you catch one inadvertently, you must kill it. There is no limit or minimum size for snakeheads.

But if you think these swimming gullets are Public Enemy No. 1 to sportsmen and women, think again. They're sporting to catch on light tackle. They are a hoot to shoot at night in shallow water with bowfishing gear. And they are delectable when prepared in any number of ways. In the 19 years since they showed up in Mid-Atlantic waterways, they have developed quite a following.

"Snakeheading has become extremely popular, to the point where we'll see five to six boats a night, whereas even five years ago, we didn't see another boat," Wetherald said. "There are a lot of reasons for that. First, it's something to do at night. Second, archers like it because it keeps them conditioned for bowhunting season. Flats shooting has been popular for years in the South, where bowfishers love their gar and flounder, but it's new to the Mid-Atlantic area. Equipment is good and getting better every year. And snakeheads are extremely good to eat. If you look back on their history in the Far East, that's why they were propagated. They're fast growers, they are prolific reproducers, and their value as table fare is excellent."

Does this sound like a despised invasive species to you? It sounds more like our relationship with another species that brings out the best and the worst of us: feral hogs.

While America's invasive hogs have their origins in less exotic locales than the snakehead, their detrimental impact on our natural habitats is pretty similar. But so is our love-hate relationship with these mammals that are a kick to hunt, even while we feel guilty for loving to chase wild pork as much as we do.

Management Crossroads

We have been conditioned to despise the species that are classified as "invasive" and "noxious." The classifications of "exotic" and "feral" are a little harder for us to categorize or hate.

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Here are some examples:

Species classified as "invasive" include the Asian carp that have infiltrated the Ohio and lower Mississippi rivers, as well as zebra mussels that were brought to the Great Lakes from Eurasia. Noxious species—this classification usually applies to weeds—are those plants that are "injurious to agricultural or horticultural crops and natural habitats or ecosystems."

Then there are those species defined as "exotic." These are the slow-burners of our landscapes. They are typically neither as aggressive nor as injurious to our native ecosystems as the invaders, but because they’re from elsewhere, they may displace or outcompete native species.

Examples of these exotics include soybeans, native to East Asia, which fuel much of the American Midwest’s agricultural economy; Chinese ring-necked pheasants, which draw so many of us to the uplands in the fall; and brown trout, which for more than a century have been a premier species for anglers across the country. But even feral cats and dogs, when they roam from those homes where they have names and collars, are considered exotic across much of the country.

This "feral" classification defines animals or plants that were once domesticated but have since lost their domestic nature and turned wild. The poster children for feral species in the U.S. is wild pigs.

So, what are wildlife managers to do when an invasive or exotic species comes to their midst? First, don't let the organism accrue a value, either commercially or recreationally. In Missouri, where feral hogs are moving in from Arkansas and Oklahoma, the state's Department of Conservation discourages shooting pigs for two reasons. First, it doesn’t want to create any recreational value for these invasive exotics. Second, biologists are concluding that shooting hogs is ineffective. Hunters rarely kill entire sounders—or family groups—of feral hogs. Some survive, and because hogs are highly adaptive, the survivors become more evasive and educated, making each generation of survivors harder to kill.

Back in Maryland, where the state-record snakehead of 19.9 pounds was caught in May 2018, there's some indication that the predatory fish are similarly becoming harder to kill efficiently.

"Bowfishing requires clear water, and tidal surges and wet springs that bring turbid runoff from the tributaries and upper Potomac are becoming more frequent, so the conditions required to target snakeheads are getting narrower and harder to predict," Capt. Wetherald said. "Meanwhile, they've been such effective predators, they're having to move to find new food and habitats. We're hearing of them traveling the big [Potomac] river to get places. If they're relocating and expanding, that’s not a good sign for other species, like largemouth, perch, trout and even striped bass."

Fluid Situation

But as fisheries managers intensify their effort to making northern snakeheads unwanted and unwelcome, another species is starting to make its presence felt in the Mid-Atlantic watersheds: the blue catfish, which is native to rivers farther south. Its resident status puts it in a strange definitional box. It's not an exotic, since it's as American as striped bass, but it certainly is invasive, especially as it shifts from a bottom-feeding scavenger to an open-water predator.

"Blue cats have been expanding their range, either because of habitat shifts or whatever," Wetherald said. "They've adapted to the point where they are moving out of their normal ecosystem, devastating crabs and eating the same baitfish as saltwater fish, and the state has removed limits and restrictions on means and methods of catching them. Five years ago you never heard of catching a blue cat while trolling open water, but now we catch as many blues while trolling as we do stripers."

Wetherald is taking advantage of the new fishery. Starting this year, he's offering a straight-up catfishing service.

"It's an opportunity that's there, people can catch numbers of big fish, and we should try to assist the state to control numbers. Sure, they're unwanted, but if they can adapt, so can we."