Zebra and Quagga Mussels
Zebra and quagga mussels are invasive species which can cause significant damage to the Colorado ecosystem.
About This Species
The zebra and quagga mussel are not native to Colorado. Colorado Parks and Wildlife is concerned by the serious threat posed to our aquatic habitats by these two mussels.
Overland transport on boats, motors, trailers and other watercraft poses the greatest risk for spreading zebra and quagga mussels. Adult mussels can attach or “hitchhike” to any surface and can live several days out of water (depending on the time of year) in moist, shaded areas. The microscopic mussel larvae (knows as veligers) can be transferred in water contained in live wells, bilge, ballast tanks or “minnow” buckets.
What are Zebra and Quagga Mussels?
Zebra and quagga mussels are not native to the nation’s rivers, lakes and reservoirs and are considered our most serious aquatic threat. They cause enormous problems for water infrastructure used for municipal, agriculture and industrial purposes by attaching to, clogging and impairing water storage, treatment and distribution systems.
Zebra mussels are native to the Black, Caspian and Azov Seas of Eastern Europe. They were discovered in the Great Lakes in Lake St. Clair in 1988 and have since spread to 33 states in the United States.
Quagga mussels are native to the Dnieper River Drainage in the Ukraine. They were discovered first in the Great Lakes in the Erie Canal and Lake Ontario in 1989 and have since spread to 27 states in the United States.
Many aquatic nuisance species have been introduced into the Great Lakes through transoceanic ships. Once in North American waters, aquatic nuisance species often hitch rides to other bodies of water on the boats, trailers, and equipment that people transport from place to place. The microscopic larvae also can be transported in bilges, ballast water, live wells, or any other equipment that holds water. Given their ability to attach to hard surfaces and survive out of water for extended periods [30 days!] Zebra and quagga mussels likely made their way to the Western USA on trailered watercraft. Boaters and anglers can inadvertently transport on waders and in bait buckets and live wells.
Infected Waters
Colorado Parks and Wildlife is monitoring the state’s waters for the introduction of aggressive invasive species, Zebra and Quagga Mussels.
Waters Positive for Zebra or Quagga Mussels
Find out moreReport Zebra or Quagga Mussels
If you see a zebra or quagga mussel, please report it to Colorado Parks and Wildlife.
File a ReportMore Information:
Physical Characteristics
Shell Shape
Quagga mussels and zebra mussels are small freshwater bivalve mollusk-animals with two shells. A medium sized zebra mussel bivalve (two shells) which is nearly triangular in shape. A medium-sized quagge mussel is bivalve (two shells) which has a more rounded triangular shape than the similar Zebra mussel. The two valves are asymmetrical thus creating a keeled edge. They are relatives of clams and oysters. It is very difficult for a non-expert to tell the two species apart.
Shell Color
The shell color of both mussels alternates between a yellowish and darker brown, often forming stripes. Color patterns are highly variable and can be attributed to environmental factors. Shell color alternates between a yellowish and darker brown often forming stripes.Size: They range in size from microscopic up to about two inches long.
Byssal Threads
Unlike native North American freshwater mussels, which burrow in soft sediment, adult zebra and quagga mussels can attach to most hard and semi-soft surfaces via tiny threads called byssal threads. Native species do not have byssal threads! These byssal threads are one of three main invasive characteristics that give zebra and quagga mussels an advantage over natives, along with rapid reproduction and their ability to filter feed at amazing rates.
Commonly Found
Zebra mussels are native to the Black, Caspian and Azov Seas of Eastern Europe. They were discovered in the Great Lakes in Lake St. Clair in 1988 and have since spread to 33 states in the United States.
Quagga mussels are native to the Dnieper River Drainage in the Ukraine. They were discovered first in the Great Lakes in the Erie Canal and Lake Ontario in 1989 and have since spread to 27 states in the United States.
Range
Many aquatic nuisance species, including zebra and quagga mussels, have been introduced into the Great Lakes in the discharged ballast water of ocean-going ships. Another method of dispersal from Europe to the United States is believed to be through transportation of attached mature adults on anchors stored internally in compartments on transoceanic vessels. Once in North American waters, aquatic nuisance species often hitch rides to other bodies of water on the boats, trailers, and equipment that people transport from place to place. Boaters and anglers can inadvertently transport ANS on waders and in bait buckets and live wells.
Zebra and quagga mussels likely made their way to the Western USA on trailered watercraft. The first discovery west of the 100th Meridian was in Lake Mead in 2007. The invasive quagga mussels found in Lake Mead in 2007 were 1,000 miles farther west than any other known colony of quagga mussels at the time. The primary method of overland dispersal of these mussels is through human-related activities, especially trailered watercraft. Given their ability to attach to hard surfaces and survive out of water for extended periods [30 days!], many infestations have occurred by adult mussels hitching rides on watercraft. The microscopic larvae also can be transported in bilges, ballast water, live wells, or any other equipment that holds water.
Habitat
Both zebra and quagga mussels can survive cold waters, but cannot tolerate freezing. They can endure temperatures between 1⁰ - 30⁰C (33⁰ - 86⁰F). Zebra mussels need waters above 12⁰C (54⁰F) to reproduce, while quagga mussels can reproduce in waters as cold as 9⁰C (48⁰F). Adult mussels are light sensitive and prefer to live in water around 200 to 300+ feet deep. They are able to live in a wide range of conditions including oxygen-depleted water.
Threats to Species
Colorado waterways and reservoirs are at serious threat by Quagga mussels, which are more cold tolerant than the well-known Zebra mussel and have been found in California, Nevada and Arizona, including Lake Mead.
Additional Information
Zebra and quagga mussels pose a great ecological and financial threat to the state. The invasion of these mussels can affect every Coloradoan and visitors in some way and the impacts could be devastating. Potential impacts include:
- Prolific reproduction
- Clog water infrastructure
- Ecological impacts
- Recreational impacts
- Economic impacts
- Social impacts
- Difficult or impossible to eradicate
- Quick spread to new waters