Ashland ODFW Finds Invasive Mussels Species That Could Cause Serious Damage to Oregon’s Waterways

ASHLAND, Ore. — The staff of the Oregon Department of Fish and Wildlife- ODFW, at the Ashland Boat Inspection Station, found alien invader quagga mussels on January 4. Located on a pontoon boat from Lake Mead, the finding is the first find of quagga mussels for ODFW crews for 2024.

This species has not been detected by ODFW in Oregon’s waterways for some time. Crews have decontaminated nine watercraft for quagga or zebra mussels as well as 327 watercraft for Eurasian Watermilfoil and other types of aquatic biofouling last year.

ODFW confirmed that- since the start of the Watercraft Inspection Stations program in 2010, they have inspected 209,620 watercraft and intercepted and decontaminated 168 watercrafts containing quagga or zebra mussels. 3,246 watercraft with other types of aquatic biofouling were similarly decontaminated.

The contaminated watercraft was decontaminated at Ashland’s inspection station, and ODFW invasive species coordinator Rick Boatner said. “We want watercraft owners to be responsible and have their vessel inspected when entering Oregon.” These mussels infiltrate Oregons’s waterways, potentially causing serious damage to streams, lakes, irrigation, and ultimately to Oregon’s water delivery systems.


Why Are Quagga Mussels Regarded As Invaders?

quagga mussels

The Quagga Mussel (Dreissena bugensis), is native to the Caspian and Black Sea regions. Round mussels measuring on average 2cm but growing to 3cm, it is lighter in color than the similar Zebra mussel.  Both quagga and zebra mussels are aquatic invasive species native to eastern Europe- although the quagga is larger, rounder, and wider, and get their names from the zebra-type stripes on their shells.

Small mussels- typically growing to the size of a fingernail, they are prolific breeders and can attach themselves to both hard and soft surfaces in freshwater ways. Native mussels are easily differentiated from the invaders because they are 3 to 4 times their size, are more oval, and are usually greenish or dark brown with visible growth rings.

  • Both invader species have had catastrophic impacts on the ecosystems they migrated to, including:
  • Clogging water intake structures (e.g., pipes and screens), increasing maintenance costs for water treatment and power plants.
  • Adversely affecting recreational activities on lakes and rivers as they accumulate on docks, buoys, boat hulls, anchors, and beaches. The shells are sharp and can cut people, potentially causing primary and secondary infections.
  • Mussels stuck to boat hulls increase drag, affecting boat steering, and engine clogging. This can lead to overheating and engine malfunctions.
  • The ecological problems arising from zebra and quagga mussel invasions are associated with the death of native species as alien invaders:
    • attach to the shells of native species, which can kill them, and
    • outcompete native mussels and other filter-feeding invertebrates for food.
  • Encrusting of lake and river bottoms can displace native aquatic arthropods needing the soft sediments for burrowing. Affecting the whole food chain, in the Great Lakes this led to the collapse of amphipod populations that fish rely on for food and the health of fish populations has been severely affected.
  • Associated with avian botulism outbreaks in the Great Lakes, quagga and zebra mussels have caused the mortality of tens of thousands of birds.
  • Because of their filter-feeding habit, it has been estimated that these mussels can bioaccumulate organic pollutants in their tissues which can biomagnify as they are passed up the food chain, as contaminated mussels are eaten by predators (such as fish), who in turn are eaten by other organisms (such as people who eat the fish).
  • Increase water acidity and decrease concentrations of dissolved oxygen caused by high populations.


Both Ashland: I-5 at the Ashland Port of Entry and Ontario I-84 at the Ontario Rest Area are open daily year-round during daylight hours. And ODFW watercraft inspection stations are open if large orange, “Boat Inspection Ahead,” signs are posted, followed by “Inspection Required for All Watercraft.” The seasonal Inspection stations in Brookings, Klamath Falls, Lakeview, and Umatilla are open from the first week of May.

ODFW has reiterated that all vehicles towing or carrying watercraft into Oregon must stop at any open watercraft inspection station so that the department can inspect for aquatic invasive species. They believe that watercraft owners are well aware of where inspection stations can be found around Oregon.


Oregon Invasive Species hotline takes calls of quagga mussels reported to be at 1-866-INVADER or


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