As more and more invasive species gain footholds around the country, American wildlife management is becoming increasingly difficult. Think of invasive species as foreign invaders capable of upsetting the natural balance through a series of cascading problems. Whether it is a new insect, plant, or large mammal that manages to establish itself on the landscape, the end result is almost always bad for native species. It is also expensive. Fighting invasive species in the United States costs taxpayers over 130 billion dollars a year. But, the good news is that hunters and anglers in America can play an important role in controlling invasive species numbers.
Successful invasive species are difficult and costly to control because they adapt well to foreign ground, quickly establish viable breeding populations and negatively impact native plants and wildlife. There is a wide range of fish, reptiles, amphibians, birds and mammals carving out new territory in the United States that meet these criteria. From Burmese pythons and monitor lizards in Florida to sea lampreys and Asian carp in the upper Midwest, our growing invasive species problem affects the entire country.
Some plants and animals from different parts of the world hitch a ride on boats or planes into America. Zebra mussels made it to the Great Lakes in the ballasts of European ships in the 1980’s. They are now present in 29 states, causing billions of dollars in damage each year. Problem cases are also the result of illegal stocking and, in some cases, intentional introduction. Illegal stocking occurs when someone selfishly introduces a non-native species into a new environment for their own enjoyment. This is a common problem in rivers and lakes and is often referred to as bucket biology. Predatory lake trout or mackinaw, have devastated native cutthroat trout in Yellowstone Lake.
Sometimes, new species are intentionally introduced for reasons that end up backfiring. Some non-native species are used to control pests. These government sponsored biocontrols often end up causing unforeseen problems. Non-native Northern pike were introduced into many western reservoirs to control non-native rough fish like carp. In Colorado, pike have escaped reservoirs and now flourish in nearby river systems, upsetting the balance of native fisheries. Non-native plant species used as ornamental displays are another potential hazard to native wildlife. This winter, in Idaho, many elk and antelope that ate non-native Japanese yew plants were poisoned and died.
Over 50,000 non-native plants and animals have been introduced into the United States. Of these, at least 4,300 species are considered invasive. It is important to distinguish the sometimes subtle differences between acceptable non-native species and harmful invasive species. Non-native ringneck pheasants were intentionally released in America over one hundred years ago and they quickly became our most popular upland bird species. Generally, they’ve done no serious harm to native wildlife. Non-native pacific salmon and steelhead fisheries introduced to the Great Lakes have created substantial recreational and economic benefits and without creating devastating environmental problems.
On the other hand, you’ve got invasive Eurasian cheatgrass and European zebra mussels, which have wreaked catastrophic environmental havoc in the United States while providing little or nothing of value. What’s more, non-native species can be considered beneficial in some parts of the United States while they’re considered deleterious in other regions. Rainbow trout are not native to most of the United States but they are one of the most popular game fish in the country. While many states spend hundreds of thousands of dollars on rainbow trout stocking programs, other states (or areas within the same state) spend money trying to prevent rainbow trout from infiltrating and disrupting threatened populations of native cutthroat trout and brook trout.
This blurry line that separates invasives and acceptable non-natives is becoming a progressively more challenging problem for wildlife managers trying to preserve native species. For example, mountain goats are not native to the Colorado Rockies. But, they are a highly coveted game animal many Colorado hunters dream about hunting someday. Even though they were intentionally introduced by the state’s wildlife managers many years ago and they’re not considered invasive, it’s clear now that they’re competing with and negatively impacting Colorado’s native bighorn sheep in some areas. It would be hard to imagine Colorado’s fish and game agency declaring mountain goats an invasive species in need of eradication, but they do present some complicated and unforeseen management issues.
Sometimes though, things aren’t so complicated and it’s obvious that some invasive species are just plain bad news for the environment. The danger with most invasive species is that they generally overcome eradication efforts once a breeding population is established, making it all but impossible to stop their expansion into new territory. The most feasible way to manage most invasive species is to try to control their numbers and this is where hunters and anglers can help.
First off, hunters and anglers can exacerbate the problem by inadvertently (or intentionally) moving invasives into a new area. For example, muddy boots and waders can spread invasive New Zealand mud snails and it is often illegal to use or release non-native baitfish in many fisheries. Hunters who use horses to access the backcountry are often required to use certified weed-free hay to feed their animals.
When it comes to managing invasive species that can be targeted by hunters and anglers, state fish and game agencies often do away with seasons and bag limits. Sometimes, a license may not even be required to hunt or fish for invasives. Targeting invasive species is a great way to add more food to the freezer and extend your hunting and fishing time. It’s also a valuable way to help out native fish and game resources.
Just because some of these species are foreign invaders doesn’t mean they live very far from most American hunters and anglers. Opportunities to hunt and fish for invasive species are common throughout the country, often close to large cities. All a hunter or angler needs to do to help is identify a nearby area where some edible invasives live and get after them.
Here is a sampling of some of the most common invasive species available to hunters and anglers in the United States:
In many parts of the United States non-native trout have drastically reduced native trout numbers through predation, competition and hybridization. Brown trout in the Eastern United States are more aggressive and adaptable than sensitive native brook trout. Meanwhile, those same brook trout are not native to Rocky Mountain fisheries and have hurt native cutthroat trout numbers in some areas. Lake trout and rainbow trout also endanger many native cutthroat trout fisheries. One of my favorite backcountry elk hunting meals is brook trout cooked over a campfire.
Northern pike are native only to parts of Alaska, the Northeast and Upper Midwest but they are present in most states in the Lower 48. In many parts of the pike’s expanded range, native fish have suffered due to their presence. This is especially true in the western half of the country. Pike are voracious feeders capable of eating large prey like threatened squawfish in Colorado, where there is no bag limit on pike. They are a tasty game fish with white flesh much like a walleye.
By now, everyone has seen a video of hundreds of Asian carp jumping clear of the water as a boat motors down a Midwestern river. In just a short time, they’ve become the largest biomass in many Midwestern fisheries and it is likely they will soon invade the Great Lakes. They have the potential to upset entire aquatic ecosystems. Alongside non-native common carp and grass carp they offer unlimited opportunities for anglers and bow fishermen. Still labeled a trash fish by many anglers, carp are considered a delicacy in Europe and are a primary food source in Asia. Invasive Asian carp are filter feeders that eat plankton. Unlike the bottom-feeding common carp, their flesh is white and firm. American anglers who overcome their prejudice against carp might find them a welcome addition to their smoker.
This toothy, aggressive invasive fish from Asia was probably established as an invasive by aquarium enthusiasts who released them as well as immigrant populations that sought to create a catchable population of fish from their homeland for live fish markets. These predators feed on native fish and amphibians. Despite eradication efforts, snakeheads breed rapidly and are present in catchable numbers in warm lakes and rivers from the Mid-Atlantic States south to Florida. Populations have also shown up in California and other states. Aggressive and easily caught with topwater bass lures, snakeheads are lauded for their firm, white flesh by anglers who pursue them.
Lionfish are native to warm, tropical waters in the South Pacific and Indian Oceans. Now, due to the release of unwanted aquarium specimens, lionfish are present along the warmer waters of the southern half of the Atlantic coast of the United States. They feed aggressively on native fish, including the young of popular fish like grouper and snapper. While they have poisonous spines, if handled carefully and properly cleaned, lionfish are excellent table fare for conventional anglers and spear fishermen.
There’s many other invasive fish species anglers can pursue. Some are exotic foreigners like peacock bass and tilapia. Others are more common game fish like smallmouth bass and yellow perch that have been illegally introduced into new locations.
Reptiles and Amphibians
Bullfrogs are a common species native to the eastern half of the United States. They’ve spread to the western half of the country, likely as a byproduct of fish stockings. Considered invasive throughout the West, bullfrogs have become a serious problem for native amphibians and western aquatic ecosystems. They will feed on anything they can catch including birds and rodents. Hunting bullfrogs with spears, gigs or bows is a fun night time activity and there are no limits where they are considered invasive. A batch of deep-fried frog legs makes it worth the effort.
Iguanas are native from Mexico south to Brazil but are firmly established in Florida, south Texas and Hawaii. Iguanas likely came into the U.S. with shipments of fruit and escaped or released pets contributed to the problem. They eat native plants and their burrows they undermine seawalls, building foundations and sidewalks. It is legal to trap and hunt iguanas with air guns in many areas. I once caught one on a fly rod by moving a bonefish fly across the sand in front of a three-footer in the Florida Keys. The tail and leg meat from that iguana was mild and reminiscent of alligator.
Eurasian collared doves
Eurasian collared doves from warmer Asian climates were unintentionally introduced into the United States, possibly from the Bahamas in the 1980’s. Twenty years later these large doves are common in most of the country but in northern climates a shorter breeding season is slowing expansion rates. The impact of these invasive birds is still unclear but competition with native bird species has been observed. With no seasons or bag limits in many states, Eurasian collared doves and offer wing shooters expanded hunting opportunities and great eating.
The wild cousins of domestic pigeons are the descendants of rock doves that nested in cliffs on the other side of the world. Feral rock pigeons are now commonplace in American cities where tall buildings and bridges mimic their natural habitat. They’re also well-established throughout rural America, nesting in barns and grain silos. While they don’t seem to directly harm native birds, pigeons are considered an urban pest and a nuisance species that feeds on important agricultural crops. Pigeons, especially young squabs spatchcocked and grilled whole, are one of the finest meals a hunter can eat and with no limits, you can eat a lot of them.
There are other common birds that are considered invasive and troublesome in the United States. Starlings are one the most numerous birds in the country, with migrating flocks numbering in the hundreds of thousands a common sight in the fall. Sparrows are another European species that many people might not realize are invasive. In most states, it is legal to hunt these birds but it is not a common practice.
Feral pigs are a popular target for hunters in the Southeast, Texas, Oklahoma and California. They are spreading fast into new areas. Wild pigs cause billions of dollars in damage a year and have proven destructive to native plants and wildlife. Wild pigs are one example of an invasive species that some hunters have, unfortunately, helped to spread through illegal stocking efforts. With no seasons or bag limits in many states, wild pigs offer hunters a lot of hunting opportunities and some fine barbecue.
Nutria, also known as copyu in their native South American range, is a large, semi-aquatic rodent released in the southern United States in the late 1800’s. They were introduced to establish a fur market that never panned out. Nutrias have expanded due their aquatic mobility and high reproductive rates. They are now found in over twenty states and are most common along the Gulf Coast. The “swamp rat” is considered invasive and destructive to natural wetlands ecosystems. They feed on native plants like cattails and bulrush that prevent erosion and filter fresh water before it reaches the ocean. Minus their thin, rat-like tail, they resemble beavers and can reach twenty pounds. Nutria hunters can kill as many as they like and they provide good eating as well as fur similar to a beaver or muskrat.
Aoudad or Barbary Sheep
In some areas of Texas and New Mexico, non-native Aoudad sheep from Africa were introduced to create new hunting opportunities. Unfortunately, wild populations of these animals compete with sensitive populations of native bighorn sheep and mule deer. The good news for hunters who can’t afford a guided sheep hunt in British Columbia or Alaska or who are still waiting to draw a once-in-a-lifetime sheep tag in the Lower 48 is that Aoudads can be hunted very affordably on your own do-it-yourself hunts. If you’re successful, you’ll be packing out a load of sheep meat through beautifully rugged, high desert country.
Other Edible Invasives
Rusty crayfish are a freshwater crustacean native to the Ohio River drainage. Due to bait bucket stocking, the rusty crayfish is now littered throughout at least twenty states outside of its original range. Its abundance has increased over time since it is very aggressive and adaptable to new environments. It competes with, preys on and replaces native crayfish as well competing for food with juvenile game fish. This, in turn, disrupts aquatic plant communities and impacts native fish populations. One egg-bearing female can establish a new population. The good news for anyone outside of the Deep South looking for a supply of mudbugs for a crawfish boil is that these large crustaceans are abundant and easily trapped throughout the country.
Chinese Mystery Snails
These large Asian snails have spread throughout the United States over the past few decades and are considered an invasive species in over twenty states. Their impacts have not been studied thoroughly, but, like many invasives, they compete with native species and eat native plants. They can be found in large colonies in lakes and slow moving rivers and are easily harvested for escargot or snail chowder. Flush them for a few days in clean water before cooking thoroughly.
As you can see, there are plenty of invasive species for hunters and anglers to target. Many of these species don’t require a special trip and they can be taken alongside native fish and game animals. Hunters and anglers interested in taking their foraging a step further should research the many edible invasive plants that can be harvested in the United States. While we may not be able to completely eradicate many harmful invasive species, hunters and anglers can help to control them and enjoy some tasty meals along the way.