Origin
Dreissena polymorpha or Zebra mussel is native to Eurasia, specifically the drainage basins of the Black, Caspian, Aral and Azov seas. It has a small triangular shell with a sharply pointed umbo (hinge end). The prominent dark and light banding pattern on the shell is the most obvious characteristic. The outer covering of the shell is generally well polished, a light tan in color with broad, dark bands across the shell. These bands can be either smooth or zigzag in shape.

Life Cycle
D. polymorpha eggs hatch then go through planktonic larval stages for up to 4 weeks. Larvae are usually moved by water flow. Once larvae reach about 350 microns in size they develop into their juvenile stage. At this point they settle to the bottom and search for a substrate to attach to by a cluster of threads called a byssus. D. polymorpha reach maturity in 1-2 years depending on conditions. The life span can range from 3 to 9 years. Adult D. polymorpha can detach to seek out more favorable conditions. Synchronized spawning occurs in reproductively mature D. polymorpha. Spawning is usually triggered by water temperature.

Distribution
D. polymorpha is considered one of the ‘World’s Worst’ invaders. They have been found in central and western Europe, Great Britain, North America, Russia and Scandinavia.

Control Efforts
Preventing infestations of D. polymorpha by proper ballast water management including mid-ocean exchange and disinfection should be a priority. Physical removal by high pressure washes can be effective. Freezing, heating to high temperatures and desiccation will control D. polymorpha.

Resources

• Aquatic Species Profiles: Zebra Mussel - USDA National Agricultural Library
• Fact Sheet - Ontarios Invading Species Awareness Program
• Wikipedia - Wikimedia Foundation, Inc
• Global Invasive Species Database - Invasive Species Specialist Group
• Invasive Alien Species Fact Sheet – Dreissena polymorpha - North European and Baltic Network on Invasive Alien Species
• Nonindigenous Aquatic Species Database - U.S. Geological Survey

Selected Images

Maps

Invasive Listing Sources

• Alberta Fisheries Act
• Everglades Cooperative Invasive Species Management Area
• Florida Conditional and Prohibited Non-Native Species Lists
• Florida Invasive Species Partnership
• Idaho Invasive Species Act
• Invasive Species of Concern in Georgia
• Maryland Aquatic Nuisance Species Plan
• Maryland Invasive Species Council - Invasive Species of Concern in Maryland
• Michigan’s Prohibited and Restricted Species
• Mid-Atlantic Field Guide to Aquatic Invasive Species
• Minnesota DNR invasive species list
• New Jersey Invasive Species Strike Team 2017 Invasive Species List
• New York Regulated and Prohibited Invasive Species - Prohibited
• Nonnative Invasive Species in Southern Forest and Grassland Ecosystems
• Ontario’s Invading Species Awareness Program Tracked Species List
• Pennsylvania's Field Guide to Aquatic Invasive Species
• Virginia Invasive Species Management Plan 2012
• West Virginia Invasive Species Strategic Plan and Volunteer Guidelines 2014
• Wisconsin's Invasive species rule – NR 40

References