Life Cycle: Submerged aquatic perennial

Leaves: Leaves are bright green, sessile, whorled, and occur in groups of 3-6. Upper leaves are 15-40 mm in length and 2-5 mm in width. Lower leaves are opposite and scale-like.

Flower: White, glossy, and wrinkled flowers emerge on the surface to 1.5 inches from the water. Flowers have three petals.

Stems: Like the leaves, stems are bright green in color. They can easily break off and can root on nodes. 

Sources:

UC Davis Weed Report

Montana Field Guide

NOAA

Found in: Submerged in water generally 1-2 meters deep, particular to warmer waters but will overwinter.

Native to: Brazil, Argentina, and Uruguay

Prevention: Often these plants are introduced when contents of aquariums are not disposed of properly. Always dispose of aquarium items in a sealed bag. Once established, it spreads easily through fragmentation, so it is important to clean, drain, dry boats, waders, boots, and all angling gear before entering another water body. 

Impacts: Creates dense mats that make recreating more difficult. These mats can also clog water intakes, allows the plant to outcompete native aquatic vegetation, and alters habitat. Contributes to reduced water quality through surplus of nutrients and oxygen uptake. 

Native lookalikes: American waterweed (Elodea canadensis), can distinguish between the two because Elodea canadensis has dark spots on leaves, and leaves are longer and less wide. 

In Montana: Not present in Montana. 

Sources: COC AIS book, http://www.invadingspecies.com/brazilian-elodea/, http://fieldguide.mt.gov/speciesDetail.aspx?elcode=PMHYD02010#:~:text=Brazilian%20Waterweed%20is%20native%20to,(DiTomaso%20and%20Healy%202003).

For Map Building:

In Montana: not present

States in US: Puerto Rico, Alabama, Arizona, Arkansas, California, Connecticut, Delaware, Florida, Georgia, Hawaii, Illinois, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Mississippi, Nebraska, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Utah, Vermont, Virginia, and Washington.

Source: USFWS, 2018: fws.gov

Hand pulling: Removal by hand or other mechanism is not recommended as it can cause further growth and spread fragments to reproduce. Removing and destroying any fragments of the plant off boats or other exposed equipment can prevent the spread.

Mechanical: Diver assisted dredging of small infestations (<2 acres) can be effective. Bottom barriers can be utilized to prevent the growth in a small area. Barriers need to be cleaned often to prevent any growth on the sedimentation that occurs on top of the barrier. In sparse populations, dewatering (drawdown) in the fall can be effective at killing plants that are exposed to the cold temperatures.

Biological control: Grass Carp (Ctenopharyngodon Idella) has been used to control Brazilian waterweed in other states; however, it is not a biological control option in Montana.

Sources:

UC Davis Weed Report

King County Noxious Weed Control Program

Life Cycle: Aquatic perennial 

Leaves: Sessile; alternate; oblong; wavy (like lasagna noodles) with tiny, serrated edges. 2-3 inches long. Green to reddish brown in color

Flower: Tiny; cream to brown; 4 petal-like lobes per flower; up to 10 flowers a spike.

Stems: Slightly flattened; branched; can grow up to 3 ft

Seed/Fruit: Seeds are 1/5 inch long; flat with pointed beak. 

Sources:

Washington State Noxious Weed Control Board

Montana State University

Minnesota Department of Natural Resources

Adirondack Watershed

Montana Noxious Weeds (Monica Pokorny and Jane Mangold)

Montana Weed Control Association 

Found in: Submerged in water 3-10 feet deep, prefers alkaline water and is an indicator of eutrophic conditions. Tolerant of low light and low water temperatures. 

Native to: Eurasia, Africa, Australia

Prevention & Spread: Reproduces via turions that can be spread to other water bodies by plant matter attached to equipment. Turions overwinter under the ice and emerge in early spring before native species. It is important to clean, drain, dry boats, waders, boots, and all angling gear before entering another water body to prevent the spread of these turions. 

Impacts: Creates dense mats that hinder recreation, outcompete native aquatic plants, and clog water pipes. Can also deplete nutrients which impacts fisheries and causes algal blooms. 

Native lookalikes: Richardson's Pondweed (Potamogeton richardsonii) also has alternate, wavy leaves, but they are not serrated and are more ovular in shape than curlyleaf pondweed. 

In Montana: Listed as a Priority 2B noxious weed; Present in Broadwater, Cascade, Choteau, Deer Lodge, Flathead, Gallatin, Granite, Jefferson, Lake, Lewis & Clark, Madison, Powell, Ravalli, Sanders, and Valley Counties

Raking: Hand cutting and raking over the course of several years can help reduce infestations. These methods should be done in the early summer to interrupt the plant’s life cycle. Raked plant matter should be bagged and removed from the site to prevent re-establishment. Removing and destroying any fragments of the plant off boats or other exposed equipment can prevent the spread.

Mechanical: Benthic or bottom barriers can be used to prevent rooting. Drawdowns in the colder months in late fall and early winter can expose the plants to cold enough temperatures to freeze turions. 

Biological control: Grass Carp (Ctenopharyngodon Idella) has been used to control curlyleaf pondweed in many states but is prohibited to use in Montana. 

Source:

Montana State University Extension

Life Cycle: Submerged aquatic perennial

Leaves: 3 to 4 bright green leaves-1 ¼ inch long with 12 to 48 threadlike divisions are whorled around the stem at each joint. Leaves rarely extend above the water surface.

Flower: Rigid, pink flowering spike, 2 to 8 inches long, held erect above water. Small, yellow, four-petaled petals in clusters. 

Stems: Slender, hairless, leafless toward base, 10 feet or longer and 1/10 inch thick. Grow to water surface then branch forming dense floating mats. Somewhat whitened when dry.

Directly taken from Montana Noxious Weeds by Monica Pokorny and Jane Mangold, based on flowering rush, etc

Found in: Submerged in water 4-10 meters deep. Can survive in moving water; prefers alkaline conditions.

Native to: Eurasia, northern Africa

Prevention & Spread: Originally introduced in water gardens it now grows and reproduces rapidly; reproduction is mainly done through fragmentation which can occur from waves or boats. Prevent the spread by cleaning, draining, and drying waders, boats, any anything else that comes into contact with the water. Place any collected plant material in plastic bags to dispose of. 

Impacts: Create dense, floating mats that outcompete native plants, disrupts recreation, and can clog water pipes. Decreases water quality by contributing to nutrient loading and sedimentation and decreasing oxygen. 

Native lookalikes: There are two native watermilfoil species in Montana, short spiked Water-milfoil (Myriophyllum sibiricum) and whorl-leaved watermilfoil (Myriophyllum verticillatum). To differentiate between these native species and invasive Eurasian watermilfoil, take a specimen out of the water, the native species leaves will remain rigid, while the invasive leaves will fall. 

In Montana: Noxious Weed: Priority 2A; Common in isolated areas of Montana

Sources: http://fieldguide.mt.gov/speciesDetail.aspx?elcode=PDHAL040B0; COC field guide; https://www.nrcs.usda.gov/Internet/FSE_PLANTMATERIALS/publications/mtpmstn8523.pdf

For Maps:

In Montana: Broadwater, Flathead, Gallatin, Garfield, Jefferson, McCone, Phillips, Sanders (Source: USGS, 2018)

In US: Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, and Wisconsin (Source: USFWS, 2018)

Hand pulling: Hand pulling smaller populations may slightly reduce the stem densities, but it is not ideal in controlling the weed. Repeated mechanical removal or harvesting can also help smaller populations. Removing and destroying stem fragments from recreational equipment will help prevent spread. 

Other Cultural/Mechanical: There are several forms of bottom barriers that can be used to smother specific areas (PVC, jute, mesh screens, etc.) These are most effective when installed in spring. Dewatering infested areas in high temperatures of the summer can suppress reqrowth. Dewatering infested areas in low winter temperatures can suppress growth as well.

Biological control: There are three herbivorous insects that have been used to control Eurasian watermilfoil with varying success. There are no current biocontrol agents available in Missoula at this time. 

Herbicide:  The following herbicides are recommended for control of watermilfoil. Aquatic deemed herbicide is necessary in all treatments of this invasive. Always consult product labels and read them carefully to ensure correct species/land management usage and chemical application.

Life Cycle: Aquatic perennial 

Leaves: Round in shape with one slit. Texture is thick and glossy. Green on the upper leaf and purplish red on the bottom. Leaf stalks can be green to reddish-purple

Flower: Floating with 17-43 white to pinkish petals and yellow stamens; petals are curved in the middle lengthwise. Flowers close at night and are very fragrant

Stems: Flowers and leaves are attached to fleshy rhizomes that are long and branching underwater. 

Sources:

Washington State Noxious Weed Control Board

Montana Monthly Weed Post

Found in: Acidic to alkaline lakes and ponds in valleys; 3-6 ft water at most. Leaves and flowers are floating. 

Native to: Eastern United States

Prevention & Spread: Introduced as an aquatic ornamental species, it has invaded the western US. To prevent further invasion avoid planting as an ornamental species and remove and dispose of any vegetation on boats, waders, or other equipment that has been in the water.

Impacts: Create dense, floating mats that outcompete native plants, disrupts recreation, and can clog water pipes. Decreases water quality by contributing to nutrient loading and sedimentation and decreasing oxygen. Has been known to cause drownings in Washington state. 

Native lookalikes:  Can be distinguished from native pygmy waterlily (Nymphaea leibergii) by fragrant flowers, fewer petals, and smaller sepals. It can be distinguished from Brasenia (watershield) by its split leaves and Yellow Pond-lily because the native pond lily has yellow flowers with inconspicuous petals.

In Montana: Listed as a Noxious Weed in Missoula County. It has only been reported in Missoula and Lincoln Counties.

Sources: MT field guide ; CoC field guide

For Map:

In Montana: Missoula, Lincoln (Source:Eddmaps, 2021)

In US: Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Idaho, Illinois, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, and Wisconsin (Source: USGS, 2018) 

The above list includes states where FWL is native. 

Hand pulling: Hand removal of all emerging leaves done over the course of 2-3 seasons has been recorded as an effective way to remove smaller infestations. 

Mechanical/Cultural: Covering the sediment with an opaque cover known as a bottom barrier can prevent photosynthesis of plants. Cutting and harvesting has been noted to be successful if it is done many times throughout the year. Harvesters are more efficient as they cut and remove the plant matter from the water simultaneously, whereas if you cut you must manually remove all plant matter. Rototilling an infestation area removes rhizomes which can result in the permanent removal of fragrant water lily. 

Biological control: There are no biological control agents available for fragrant waterlily.

Source:

Washington State University Kitsap County Extension

Life Cycle: Submerged aquatic perennial  

Leaves: Leaves are pointed and bright green with a serrated edge. They are arranged in whorled groups of 3-8.

Flower: Flowers are thread-like and tubular. Petals are translucent white to reddish in color.

Stems: Stems are thin and long. When the stem nears the water surface it starts to grow horizontally forming a vegetative mat.Stems are easily fragmented, and most reproduction is done vegetatively.

Sources: 

US Fish and Wildlife Service

UC Davis Weed Report

Montana Field Guide

Found in: Slow moving water and lakes, depths between 20 cm to 7 meters

Native to: Asia 

Prevention & Spread: Introduced as an aquarium plant and is spread through improper disposal. Once introduced, it can reproduce through rhizomes, tubers, turions, or seeds. To prevent introduction, dispose of all aquarium plants in secured plastic bags and clean, drain, and dry all equipment that has touched water before entering another body of water. 

Impacts: Create dense, floating mats that outcompete native plants, disrupts recreation, alters habitat, and can clog water pipes. Decreases water quality by contributing to nutrient loading and sedimentation and decreasing oxygen. 

Native lookalikes:  American waterweed (Elodea canadensis) has spotted leaves. 

In Montana: Not currently present in Montana

Sources: MT Field Guide and COC field guide

For Maps:

In Montana: Currently not in MT

In US: Florida, Oklahoma, New Jersey, Ohio, North Carolina, Illinois, New York, Tennessee, Maryland, Texas, Pennsylvania, Arkansas, Louisiana, Virginia, Alabama, Georgia, Massachusetts, Maine, Connecticut, Delaware, West Virginia, Indiana, Wisconsin, Iowa, Missouri, Washington, California, Arizona, Iowa, Missouri, Mississippi, Alabama, South Carolina, Tennessee, Kentucky (Source: EDDmaps, 2021)

Harvesting/Cutting: Harvesting or cutting of hydrilla is not recommended as it can stimulate growth and spread plant fragments to start new populations. Removal of fragments of hydrilla from any equipment (boats, etc) that has it is recommended to reduce the spread. 

Dredging: Using divers to dredge 18 inches of the sediment can help eradicate hydrilla. This is most effective in small areas (<2 acres).

Drawdown: Drawdown should be done in mid-summer and can reduce the production of the tuber bank. Drawdown in the winter is not effective as the tubers form well below the sediment. 

Biological control: The grass carp has been noted as the most effective biocontrol agent for hydrilla; however, the grass carp is prohibited in the state of Montana. 

Source:

UC Davis Weed Report

Life Cycle: Aquatic perennial 

Leaves: Has both an emergent and submerged leaf form. Leaves are whorled with 20 leaflet pairs per leaf. Leaves appear to be feather-like. Leaves that are emergent are greener and more divided while submergent leaves are more reddish orange, less divided, and smaller. 

Stems: Stems are blue-green in color and can grow up to 5 feet long. Reproduction occurs vegetatively, when an entire plant or fragment breaks off and roots via nodes.

Sources:

US Forest Service

NOAA

CABI

Found in: Shallow, flowing water, but will establish in deeper water with good nutrients. 

Native to: The Amazon

Prevention & Spread: Introduced through improper disposal of aquarium plants and as an aquatic ornamental species. Once introduced, it spreads through fragmentation. To prevent the spread dispose of all aquarium plants in secured plastic bags and clean, drain, and dry all equipment that has touched water before entering another body of water. 

Impacts: Rhizomes create dense mats that disrupts recreation, alters habitat, and can clog water pipes. Decreases water quality by contributing to nutrient loading and sedimentation and decreasing oxygen. 

Native lookalikes:  n/a

In Montana: Not currently present in Montana

Sources: MT Field Guide and COC field guide

For Map: 

In Montana: Not currently present

In US: Alabama, Arizona, Arkansas, California, Delaware, District of Columbia, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Massachusetts, Michigan, Mississippi, Missouri, Montana, New Jersey, New Mexico, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, Washington, West Virginia, Wisconsin, Connecticut, Rhode Island, Vermont, Maine, Colorado, Nevada, New Hampshire, and Utah (Source: USFWS, 2018)

Hand Pulling: Hand pulling can be effective in small areas as long as emergent shoots, submersed shoots, roots and rhizomes are all removed. Cutting and raking are not recommended and can increase growth. Removal of fragments of parrot feather milfoil from any equipment (boats, etc) is recommended to reduce the spread. 

Drawdown: Drawdown of the water level during the winter can kill plants. 

Biological control: The grass carp has been noted as the most effective biocontrol agent for parrot feather milfoil; however, the grass carp is prohibited in the state of Montana. 

Source: 

Rutgers New Jersey Agriculture Experiment Station

Life Cycle: Macro-algae

Roots: Clear, root-like filaments that anchor it to the sediment

Leaves and stems: Thin, bright green branchlets are variable in length, arranged in whorls (radiating out from a single point) around the stem. Branchlets typically extend in acute angles away from the stem nodes. Tips of the branchlets may have irregularly-lengthed forks or divisions.

Reproductive Structures: White, star-shaped bulbils (asexual reproductive structures) the size of a grain of rice form on clear threads at the base of the plant and may be found at or below the sediment surface. Small, orange spheres called antheridia (male reproductive structures) may be visible near the tips of the branchlets.

Sources:

https://www.michigan.gov/documents/invasives/egle-ais-nitellopsis-obtusa-strategy_708937_7.pdf

https://www.dnr.state.mn.us/invasives/aquaticplants/starrystonewort/index.html

Found in: Water with slow flow in depths between 1-5 meters

Native to: Eurasia

Prevention & Spread: Introduced into the Great Lakes through ballast water. It has since spread via vegetative fragmentation and bulbils that can be in mud. To prevent further invasion, it is key to clean, drain, and dry boats, waders, boots, and all angling gear before entering another water body.

Impacts: Creates mats that can disrupt recreation, decrease visual aesthetics, outcompete native plant species, and alter habitat for fish.

Native lookalikes:  n/a

In Montana: Not currently present in Montana

Sources: MT Field Guide and COC field guide

For Maps:

In Montana: Currently not in Montana

In US: New York, Vermont, Minnesota, Michigan, Wisconsin, Indiana, Ohio (Source: USGS, 2020)

Life Cycle: Submerged perennial aquatic weed

Leaves: Floating and heart shaped. Green to green-yellow in color sometimes with purple undersides. 2-5 inches in diameter. Edges are scalloped. 

Flower: Bright yellow, five frilly petaled flowers with 2-5 flowers per node. Can bloom between May and October.

Stems: Stalks extend a few inches out of the water with the flower on top.

Sources:

UC Davis Weed Report

USGS

https://www.adk.org/aquatic-invasive-species-yellow-floating-heart/

Found in: Slow moving rivers, ponds, and lakes.

Native to: Eurasia

Prevention & Spread: Introduced as an aquatic ornamental species. To prevent further invasion avoid planting as an ornamental species and remove and dispose of any vegetation on boats, waders, or other equipment that has been in the water.

Impacts: Create dense, floating mats that outcompete native plants, disrupts recreation, and can clog water pipes. Decreases water quality by contributing to nutrient loading and sedimentation and decreasing oxygen. 

Native lookalikes:  n/a

In Montana: Currently not found in Montana. 

Sources: MT Field Guide

For Maps:

In Montana: Not present

In US: Arizona, Arkansas, California, Connecticut, District of Columbia, Florida, Idaho, Illinois, Indiana, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Missouri, Nebraska, New Jersey, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Texas, Vermont, Virginia, Washington, and Wisconsin (Source: USFWS, 2018)

Size: The largest frog species in North America, adults are 3-6 inches long and can weigh up to 2 lbs. Tadpoles are about 4 inches long at most. 

Color: Adults are pale to dark olive green with darker spots with white-yellow undersides. Males have a yellow throat and are slightly smaller than females. Tadpoles are green with dark spots with a white-yellow underside. 

Shape: Adults have large eardrums (tympanum) that appear as folds from their ear to their ear. Folds on males are twice as big as their eye. Males also can be identified by their loud, deep call during mating season (June- August) 

Habitat: Ponds, wetlands, and other slow-moving water with abundant emergent vegetation. They are tolerant of low temperatures and can hibernate in substrate in below freezing temperatures. 

Native to: Eastern and central North America. 

Spread and Prevention: Originally introduced outside of native range via escape from aquaculture operations as well as intentional release of pet bullfrogs into the wild. Once escaped, they disperse by swimming or being carried by water flow. They are prolific reproducers and can lay up to 20,000 eggs at a time. The easiest way to prevent invasion is by not releasing pet frogs. 

Impacts: Bullfrogs will eat anything they can swallow including native frogs, and have been linked to the decline of many native amphibians throughout the western US. They also eat rodents, birds, fish, and bats. 

Native Lookalikes: Can be distinguished from native frogs by their large size (3-6 inches long, up to 2lbs). 

In Montana: Present in the Flathead, Blackfoot, Clark Fork, Yellowstone, and Bitterroot Watersheds

Source: COC field guide, MT Field Guide.

For Maps: 

In US: See below map created 10/21 for distribution Sourced from: https://nas.er.usgs.gov/queries/factsheet.aspx?SpeciesID=71

In MT: Flathead, Blackfoot, Clark Fork, Yellowstone, and Bitterroot Watersheds

Size: Adults are between 3-5 cm in length. 

Color: Generally yellow or tan in Montana. Darker colors are usually associated with other regions 

Shape: Triangular shaped shell with concentric ridges. Tiny, serrated teeth visible when open.

Habitat: Prefer sand and gravel substrates in running water, but can be found in the sediment of lakes, streams, and reservoirs.

Native to: Asia, Africa, Australia.  

Spread and Prevention: Spread in North America is due to human activities that include accidental introduction via aquaculture operations and bait bucket introductions. Larvae can also free float or attach to debris to disperse long distances. To prevent further spread, do not use Asian clam as bait and ensure that you clean, drain, and dry any fishing equipment, boats, or anything else that has come into contact with water. 

Impacts: Can outcompete native mussels for resources, alters substrate habitat, and can clog water intake pipes, irrigation, and other industrial water uses. 

Native Lookalikes: Can be distinguished from native pea clams by its hard shell that will not crack under pressure from fingers. 

In Montana: The only reported observations in Montana have been at Lake Elmo

Source: COC field guide, MT Field Guide.

In US: See below map from USGS on US distribution or visit nas.er.usgs.gov

Size: Shell is 12-15 mm in length

Color: Shiny, pale brown shell

Shape: Coiled spiral shell, with ~5 coils and a teardrop opening. 

Habitat: Commonly found in freshwater ponds, shallow lakes, and canals attached to the substrate or aquatic macrophytes

Native to: Europe

Spread and Prevention: Faucet snails were first introduced to the Great Lakes through cargo ship ballast water. The species has since spread throughout the US by boats and other water equipment. They can survive up to a month in dried mud, so to prevent the spread, clean, drain, and dry any fishing equipment, boats, or anything else that has come into contact with water. 

Impacts: Are vectors of parasites that are spread to waterfowl when ingested and have been attributed to massive die-offs. Also outcompete native snails for resources and can clog intake screens and pipes. 

Native Lookalikes: COULD NOT FIND

In Montana: Lake Frances, Smith Lake, Upsata Lake, Rattlesnake Reservoir, and Flathead Lake

Source: Minnesota DNR, MT Field Guide, USGS

For Maps: 

In MT: Lake Frances, Smith Lake, Upsata Lake, Rattlesnake Reservoir, and Flathead Lake

In US: Washington DC, Illinois, Montana, Iowa, Maryland, Michigan, Minnesota, New York, Ohio, Pennsylvania, Vermont, Virginia, Wisconsin (Source: USGS, 2021)

Size: 4-6 mm (⅛ in) in length

Color: Shell colors vary from gray and dark brown to light brown

Shape: Shell is coiled to the right, with 7-8 coils separated by deep grooves

Habitat: Lives in the substrates and in flowing water or cool lakes and especially thrives on poor water quality with lots of algae to feed on. Does not tolerate below freezing temperatures

Native to: New Zealand

Spread and Prevention: New Zealand mudsnails were first introduced to the Great Lakes through cargo ship ballast water. The species has since spread throughout the US by boats and other water equipment. They can survive up to a month in dried mud, so to prevent the spread, clean, drain, and dry any fishing equipment, boats, or anything else that has come into contact with water.

Impacts: They outcompete native snails, mussels, and insects that native fish feed on, which can significantly impact populations. 

Native Lookalikes: COULD NOT FIND

In Montana: Present in the following watersheds: Beaverhead; Bitterroot; Gallatin; Lower Bighorn; Madison; Red Rock; Ruby; Upper Missouri; Upper Missouri-Dearborn; Upper Yellowstone; Yellowstone Headwaters

Source: USFWS, USGS, MT Field Guide, California Department of Fish and Wildlife

For Maps: 

In MT: Beaverhead; Bitterroot; Gallatin; Lower Bighorn; Madison; Red Rock; Ruby; Upper Missouri; Upper Missouri-Dearborn; Upper Yellowstone; Yellowstone Headwaters

In US: Arizona, California, Colorado, Montana, Idaho,, Illinois, Maryland, Michigan, Minnesota, Nevada, New Jersey, New Mexico, Nevada, New York, Oregon, Ohio, Pennsylvania, Utah, South Dakota, Washington, Wisconsin, Wyoming (Source: USGS, 2021)

Characteristics, Quagga: 

Size: Larvae are microscopic, young mussels are as small as a grain of sand, and adults can be about the size of a fingernail (4 cm)

Color: Dark concentric rings on shell, bands in colors that range from cream to black. Paler color closer to the hinge.

Shape: Convex ventral side that will cause it to tip over if placed on side (distinguishes quagga from zebra mussels). The mid-ventral line is uneven. Round in shape with tapering at hinge. 

Characteristics, Zebra:

Size: Larvae are microscopic, young mussels are as small as a grain of sand, and adults are about 2.5 cm long

Color: Usually marked with a zigzag pattern that can range from brown to yellowish white in color. 

Shape: Flat ventral (underside) and more triangular in shape than quagga. Straight mid-ventral line. 

Habitat: Lakes, rivers, and reservoirs. Attaches to any hard surface via byssal threads (boats, rocks, cement, etc.) 

Native to: Eurasia

Spread and Prevention: Originally introduced in basalt water in the Great Lakes. The mussels were able to spread rapidly due to free floating larvae and the ability to attach to boats that would be introduced into new water bodies. To prevent the spread to unimpacted waters, inspect waders, boats, and fishing equipment and clean, drain, dry. 

Impacts: Cause massive problems for agriculture because of their ability to clog irrigation and water uptake pipes. Can also impact recreation because they infest beaches and lake bottoms and are sharp enough to cut people. Impact native mussels by attaching to them and/or outcompeting them for resources. Can also drastically alter the habitat of a water system. 

Native Lookalikes: Can be distinguished from native mussels because of the ability to attach to hard surfaces. Native mussels use their foot to attach to sediments.

In Montana: Larvae were found on Canyon Ferry and Tiber reservoirs in 2016, but no adult species have been located since. After monitoring, Canyon Ferry has been delisted as a suspect reservoir. 

Source: COC field guide, USGS 

For Maps: 

In MT: No adults, suspect larva in Tibor Reservoir 

Size: Adults can be as large as 12 inches. 

Color: The color of the carapace (shell) can vary between greenish yellow to grey and brownish and is marked with yellow lines. The underside of the shell is lighter with dark spots. Skin is generally dark green with white or yellow striping. The most distinguishable characteristic is the red stripe behind its eye.  

Shape: The carapace is oval shaped with sharp edges and a rough face. The underside is flat and smooth. 

Habitat: Ponds, lakes, marshes, and in slow-moving rivers that have soft, muddy bottoms.

Native to: Southeastern US through Central and South America

Spread and Prevention: A common pet, these species have become an invasive species through abandonment in the wild by owners that no longer want them. The best way to prevent the spread of the species is to not release any pets into the wild.

Impacts: Can spread diseases to native turtles and cause further impact by their ability to outcompete native counterparts.

Native Lookalikes: Native painted turtle (Chrysemys picta) have vibrant colored undersides whereas red-eared sliders do not. Red-eared sliders also have more domed shells.

In Montana: Have been found in ponds in Helena, Missoula, and Billings

Source: MT Field Guide, Nature Mapping Foundation 

For Maps:

In Montana: Helena, Missoula, Billings

Size: Adults can be up to 6 inches long. 

Color: Body is light to dark brown with dark rusty colored spots on either side of the carapace (shell). Claws have black bands at the tips. 

Shape: Have long antennae and two claws. Closed claws create an oval-like shape.

Habitat: Lakes, streams, and wetlands with lots of cover (rocks, logs, and trees). 

Native to: Ohio River Basin

Spread and Prevention: Spread from native habitat occurred due to their use as fishing bait. Once introduced, they can spread on their own to connected waters. A single female can produce on her own with stored sperm and can lay 80-575 eggs. To prevent the spread of the species it is important to not use the species as live bait or release rusty crayfish kept as pets.

Impacts: Are aggressive towards native crayfish species, which can cause their displacement. They also consume native fish eggs and compete for food with fish. 

Native Lookalikes: Native crayfish are smaller than the rusty crayfish and lack the rust colored spots. Unlike native crayfish, rusty crayfish do not burrow. 

In Montana: Has not been located in Montana at this time. 

Source: MT Field Guide, COC field guide, Minnesota DNR

For Maps:

In MT: Not currently present

In US: Illinois, Minnesota, Michigan, Ohio, Pennsylvania, Vermont, Wisconsin (Source: USGS, 2021)

Size: Maximum carapace size is 50 cm, with an average size of about 36 cm. Average weight is 16 kg.

Color: Head and shell are green to dark brown, skin is more yellowish and lighter compared to shell. 

Shape: Carapace has jagged scales on top and serrated edges towards the back. Tail is almost as long as the shell and has a jagged crest of scales. It cannot fit its body into its shell. Legs are very thick and strong with heavy claws. 

Habitat: Ponds, lakes, slow moving streams, preferring muddy bottoms.

Native to: Eastern United States (including east of the continental divide in Montana)

Spread and Prevention: In non-native range, introduction was most likely from illegal pet release. Turtles can travel via water and over land. Snapping turtles can live to be 50 years old and can start reproduction around age 4. To prevent the spread, never release a pet snapping turtle into the wild. 

Impacts: Can pass parasites to native turtle species (Oregon). Has the ability to eat anything it can fit in its mouth, which can impact native plants and animals.

In Montana: Native to Montana east of the Continental Divide. West of the divide snapping turtles have been observed in the Missoula area in the Clark Fork Watershed

Source: MT Field Guide, Oregon Department of Fish and Wildlife

For Maps: 

In US: Arizona, California, Montana, Colorado, Florida, Guam, Idaho, Nevada, New Mexico, Oregon, Puerto Rico, Washington, Utah (Source: USGS, 2021)

In MT: Observed on Rattlesnake Creek (Missoula) and Milltown State Park