Our Aquatic Invaders


Montgomery County’s diverse community of native plants and animals are at risk.  There are invaders in their midst!  Who are these invaders?

Invasive species:

  • Do not naturally occur in Montgomery County

  • Spread through human introduction

  • Negatively impact native species

Invasive species are a problem throughout the world.  In 1999, there were more than 50,000 invasive species documented throughout the United States alone!  (Pimentel et al. 1999).  

Montgomery County in particular, is home to hundreds of invasive species! Most of these invaders are plants but there are many animals as well. Here are our featured 5 invaders.


Featured Five Invasives:


Image of Snakehead Northern Snakehead



Image of Green Sunfish Green Sunfish



Image of Goldfish Goldfish



Image of Virile Crayfish Virile Crayfish



Image of Corbicula Corbicula




Potential Future Threats:

  • Zebra Mussels

  • Rusty Crayfish

  • Asian Carp

  • Rock Snot



Why Do We Care?

The bad news: Invasive species are of local, national, and global concern and have serious consequences to society.

As of 2005:

  • Invasive species cost over $120 Billion annually in the US alone (Pimentel al. 2005).

  • More than 40% of threatened and endangered species were listed due to risks associated with invasive species (Pimentel et al. 2005).

  • Over 300 species of invasive plants have been documented in Montgomery County, the second most of counties in the State of Maryland!

The good news: We can do something about it!


Image of a Rusty Crayfish

The Rusty Crayfish is a potential future invader.


What Can I Do to Help Stop Invasive Species?

There are three ways we can help stop the spread of invasive species:


1. Stop New Introductions

  • Do not release pets or bait

  • Do not use non-natives in your garden

  • Clean your boat between uses

  • Do not move firewood or other plant material


2. Manage Existing Invasive Species

  • Remove existing invasive plants from gardens and yards

  • Follow regulations for the possession of invasive species

  • Maintain environmental health


3. Outreach and Reporting

  • Tell your local garden center to stock native species

  • Work with your community or home owners association

  • Report new introductions to authorities


Learn More: