You may not see them, but small hitchhikers can cling to your boats, trailers, fishing gear, kayaks, and paddleboards. These hitchhikers are aquatic invasive species like plants, fish, and mussels. Once introduced to a body of water, they can displace native species, clog motors, damage water delivery pipelines, and degrade water quality. Boats and boating equipment are the primary source of accidental introduction of aquatic invasives to new waterways. That’s why California’s Clean, Drain, Dry campaign encourages everyone who enjoys the water to take simple steps to stop the spread and keep the waterways clean and safe for everyone to enjoy.
Sneaky Ways Invasive Species Spread
Invasive plant species, like hydrilla and Caulerpa prolifera, spread when plant fragments or seeds get caught on boats, trailers, or equipment. Invasive mussels, like quagga and zebra mussel, attach themselves to boat hulls, motors, anchors, and trailers, or hide in standing water tanks. Additionally, microscopic larvae and small plant fragments can survive undetected in even small amounts of water
One of the newest aquatic invasive species threatening California is the golden mussel, Limnoperna fortunei, first detected in the Sacramento-San Joaquin Delta in 2024. Unlike other invasive mussels, the golden mussel can survive in a wider range of conditions, increasing its potential to spread quickly throughout California’s waterways. Like quagga and zebra mussels, golden mussels attach to boats and equipment, making them easily transported to other locations.
What Can You Do?
While the California Department of Fish and Wildlife is leading the state’s response to these threats—investigating pathways of spread, expanding inspector training, and raising public awareness—we all play a critical role in the effort by following Clean, Drain, Dry practices every time we visit our favorite lakes and rivers.
Prevent the spread of aquatic invasive species by using this checklist to properly clean, drain, and dry your equipment after visiting a freshwater lake, river or stream:
- Inspect all watercraft and equipment.
- Clean any visible mud, plants, fish or mussels from watercraft and equipment.
- Drain all water, including from lower outboard unit, ballast, live-well, buckets, and anything else that contains water.
- Dry everything for at least five days or with a towel before reuse.
- Dispose of debris and unwanted bait, worms, and fish parts in the trash.
- Report any mussels or suspected invasive species you find to the California Department of Fish and Wildlife hotline at (866) 440-9530 or email: Invasives@wildlife.ca.gov and to the local marina manager or harbormaster.
For detailed guidelines and resources, visit the California State Parks Division of Boating and Waterways' Clean, Drain, Dry page.
Top banner image: California State Parks staff conducting mussel surveys in Merced County, California. Photo by Xavier Mascareñas, California Department of Water Resources.