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4 Invasive Species You Can Eat in Iowa

  • 8/26/2016 4:14:00 PM
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Autumn olive, silver carp, garlic mustard and rusty crayfish are some of Iowa's edible invasive species (always learn from an experienced forager) | Iowa DNRAccording to the National Invasive Species Information Center, invasive species are plants or wildlife that thrive and spread aggressively outside their native habitat and cause economic or environmental harm. Many are quite tasty, and eating them helps reduce further proliferation in the environment. As always, learn to identify wild edibles from an experienced forager first.

Asian Carp (Hypophthalmichthys nobilis (Bighead Carp),
Hypophthalmichthys molitrix (Silver Carp)

Bighead and silver Asian carp were introduced to North America through fish farming operations in the Mississippi River basin, but unfortunately they escaped containment due to flooding in the 1970s. Since then they’ve traveled upriver, and today many Iowa waterways are affected. This poses huge ecological concerns because these carp are very large (some can weigh more than 100 pounds), produce a large number of offspring (one female bighead carp can produce nearly 2 million eggs per year), eat voraciously (up to 20 percent of their body weight per day), live a long time (10 to 20 years) and can pose a risk to recreationalists—silver and occasionally bighead carp may leap several feet out of the water when frightened.

You can help by eating up these invaders, which are highly recommended for everything from fish tacos to steamed flaky meat for salads. DNR biologist Kim Bogenschutz says the meat itself is firm, white, flaky, and mild tasting, but there are a lot of bones. Luckily, these carp are considered “rough fish” and have no length requirement or bag limit for harvesting, so as long as you have a valid sports fishing license you can take plenty with a pole, bow or spear. 

Autumn olive, silver carp, garlic mustard and rusty crayfish are some of Iowa's edible invasive species (always learn from an experienced forager) | Iowa DNRWhile carp have not been a popular food fish in Iowa past, it’s more of an image problem than an edibility problem. Common carp are bottom feeders and sometimes taste “muddy,” but Asian carp are plankton-feeders with a much milder flavor. These fish are even considered a delicacy in their native ranges. For the best-tasting carp, gut your catch and put it on ice immediately after catching, and rinse the filets well before cooking. This is especially important for Asian carp because the flesh can deteriorate quickly, and transporting live Asian carp is illegal. Other recipes suggest scoring carp meat thoroughly, spicing it heavily, soaking it in milk or vinegar to remove any unpleasant taste.

For more information on cleaning Asian carp, Kim Bogenschutz recommends the following Youtube video by USGS researcher Duane Chapman:


Autumn Olive (Elaeagnus umbellata)

This species was named for its leaves’ similarity to those of actual olives, although the two are unrelated and the fruit of the autumn olive is more like a berry. It’s native to east Asia, but autumn olive has been formally documented in at least 19 Iowa counties, and DNR biologist John Pearson says that it likely occurs throughout  the state.

This plant is notorious for shading out the competition—individual stems can be more than 20 feet long, and proliferate quickly by producing large numbers of berries that ripen in late August. The leaves are long and silvery, and the tubular flowers are white and fragrant, blooming in April.

To combat this invader, collect and eat the bright red, gold-speckled berries—they’re described as tart like a cranberry with seeds reminiscent of almonds. Cooked preparations are ideal because heating the berries kills the seeds inside.

Best of all, you can forage for autumn olives and other berries for free on some public lands, although you should contact any park’s or preserve’s manager to check their policies beforehand. Remember to thoroughly identify any foraged food items by learning from a skilled foraging expert, and if you’re unsure, don’t eat them.

Note: A close relative of the autumn olive, the Russian olive,  also occurs widely in the state and is considered invasive for similar reasons. The fruit is not quite as desirable because it’s dry and mealy, but the taste is still pleasant and described like persimmon.


Autumn olive, silver carp, garlic mustard and rusty crayfish are some of Iowa's edible invasive species (always learn from an experienced forager) | Iowa DNRRusty Crayfish (Orconectes rusticus)

Iowa has seven native species of crayfish, but you wouldn’t generally eat them because they tend to be small. Invasive rusty crayfish are significantly larger (adults can be more than four inches long, not including claws!) which is part of the reason they’re a problem. With their larger body size and aggressive behavior, rusty crayfish easily outcompete smaller native species for food and territory, and they reproduce at an alarming rate—a large female may hatch up to 450 eggs every spring. Fortunately, Iowa populations are still relatively small.

You can help knock back their numbers even further and fill up your plate, because as long as you have a valid sport fishing license, there is no limit on the number of crayfish you can harvest from public waters. To identify rusty crayfish specifically, look for a dark brown individual with disproportionately large, black-tipped claws (each one can be comparable to the size of the body) and rust-colored spots on either side of the carapace in creeks, rivers and lakes with gravel bottoms. You may have better luck at night because these animals are nocturnal.

Once you’ve found a rusty crayfish population, you can catch them by hand (carefully!), with a net or trap. Traps are recommended for catching enough to eat—try to get about 10-15 per serving, and store them in a drained, chilled cooler until you get home. According to Iowa law, they must be dead before transport. When you get home, bring a pot of water to a boil and toss in the crayfish for approximately five minutes if you’re going to freeze the meat and eat it later, or 10 minutes if you’re going to eat right away. Crayfish are common in Cajun and Scandinavian cuisine, so finding more specific recipes is fairly simple.


Autumn olive, silver carp, garlic mustard and rusty crayfish are some of Iowa's edible invasive species (always learn from an experienced forager) | Iowa DNRGarlic Mustard (Alliaria petiolata)

Even the name sounds tasty! A native of Europe, this herb was introduced to the eastern U.S. in the mid-1800s by settlers. Since then, it has spread all the way to the west coast, Canada, and even Alaska. This plant owes most of its success to the tremendous amount of seeds each individual can produce—600 is fairly average, but a 1993 study found a robust individual can produce nearly 8,000. Combine that with the plant’s ability to self-pollinate, produce allelochemicals (secretions that prevent the growth and survival of other plants), and thrive in deep shade, plus the fact that grazing animals don’t like to eat it—you end up with garlic mustard unfortunately but easily dominating understories of forests across the nation.

Luckily for us it’s nutritious, available year-round, easy to identify and every part of the plant is edible at one time or another. You can use raw leaves and flowers in salads sparingly all growing season (leaves can be bitter especially if grown in full sunlight), use the root like horseradish any time of year, use young stalks like asparagus, blanch leaves for pesto or simply eat them like cooked spinach. The taste of cooked leaves is similar to broccoli rabe, as broccoli and garlic mustard are from the same plant family.

To find garlic mustard, look for plants with coarse-toothed, heart-shaped leaves. Since this plant has a two-year life cycle, first-year plants will be rosettes on the ground whereas a second-year plant grows a stalk up to three feet high. Clusters of small white flowers bloom at the top of second-year plants from May through June.


Remember: As always, learn to identify wild edibles from an experienced forager first.


For more ideas, check out our Outdoor and Wild Recipes Board on Pinterest.