**Quagga Mussels** (*Dreissena rostriformis bugensis*) are a highly invasive freshwater bivalve species native to Ukraine. Along with the related Zebra Mussel, they are one of the most damaging invasive aquatic species in North America and Europe. The conflict is severe ecological and economic damage: they **filter massive amounts of plankton**, disrupting the base of the food web, and their sharp shells cause **biofouling** (clogging) of water intake pipes, dams, cooling systems, and boat hulls, leading to millions in maintenance and infrastructure costs.
Taxonomy and Classification
Quagga Mussels belong to the class Bivalvia. They are sessile (immobile) as adults, attaching to hard surfaces using strong, sticky **byssal threads**. They reproduce rapidly and can survive in deeper, colder water and on softer substrate than the related Zebra Mussel, allowing them to spread more extensively.
Physical Description
Adult Quagga Mussels are small, 1/2 to 1.5 inches long.
- **Appearance (Key ID):** D-shaped shell, often banded with light and dark markings, or solid white/brown. Unlike Zebra Mussels, they are often slightly **rounded or asymmetrical** and lack the flat ventral side, making them unstable when placed on a flat surface.
- **Larva (Key ID):** The microscopic, free-swimming larval stage (**veliger**) allows them to spread rapidly through water currents before settling.
- **Conflict Sign (Key ID):**
- **Fouling:** Massive clusters growing on any submerged hard surface (rocks, pipes, boat hulls, docks).
- **Clarity:** Excessive water clarity due to massive filtration of plankton.
- **Conflict:** Ecosystem disruption and massive infrastructure damage.
Distribution and Habitat
Quagga Mussels are established in the Great Lakes and many major river systems and western reservoirs of North America. Their habitat is freshwater lakes, rivers, and reservoirs, where they can tolerate a wider range of temperatures and salinities than other mussels.
Behavior and Conflict
The conflict is high economic cost and environmental degradation.
- **Infrastructure Clogging:** Their colonization of pipes drastically reduces water flow and requires expensive chemical or mechanical removal.
- **Ecological Change:** By removing phytoplankton, they shift the energy balance away from open water and toward the benthic (bottom) environment, favoring bottom-feeding fish and promoting the growth of nuisance algae (like *Cladophora*).
- **Rapid Spread:** They are primarily spread by **human activity** (trailered boats, equipment, fishing gear) moving contaminated water or attached mussels between water bodies.
Management and Prevention
Control is aggressive prevention and source-specific treatment.
- **Clean, Drain, Dry:** All boats and gear must be thoroughly **cleaned** (with hot, high-pressure water), **drained** (of all bilge and ballast water), and completely **dried** before moving to another water body.
- **Chemical:** Use of chlorine or other approved molluscicides (e.g., copper-based) to kill mussels attached inside pipes and water systems.
- **Physical:** Manual scraping, high-pressure washing, or heat treating (hot water immersion) for non-plumbing surfaces.
Conservation and Research
Quagga Mussels are managed as severe invasive species. Research focuses on developing rapid DNA detection methods for veligers in water samples, effective anti-fouling coatings, and biological controls that specifically target the mussel population.