Aquatic invasive species (AIS) are among the greatest threats to our lakes, rivers, and oceans. From microscopic mussels to sprawling aquatic plants, these invaders hitch rides on boat hulls, propellers, trailers, and gear, spreading silently from one body of water to another. Fortunately, with a few informed steps and consistent habits, boaters can play a significant role in stopping this ecological threat.
Aquatic invasive species are non-native organisms that thrive in environments where natural predators or controls are absent. Common examples include zebra mussels, hydrilla, and spiny water fleas. These species reproduce aggressively, overtaking ecosystems, clogging water intakes, and damaging boat motors and docks. AIS threaten biodiversity and create enormous economic burdens. According to the U.S. Fish & Wildlife Service, invasive species cost the U.S. economy more than $120 billion annually and affect fisheries, tourism, and infrastructure.
Aquatic invasive species don't need much help to travel, and unfortunately, our everyday boating activities often provide the perfect ride. Most of the time, boaters, anglers, and other recreational water users don't even realize they're giving invasive plants, animals, or microorganisms a free trip to the next lake or river.
Large shipping vessels and yachts often carry ballast water to help balance and stabilize their cargo. This water is taken on in one port and released in another, sometimes halfway around the world. But this ballast water can carry microscopic life, like larvae, plankton, bacteria, and even tiny crustaceans. When the water is released in a new location, these organisms may find ideal conditions to thrive and multiply. This is how the European green crab and Asian shore crab were introduced to North American coasts.
After a day on the water, bits of plants or mud clinging to your trailer, anchor line, or wading boots may seem harmless. However, small fragments of plants like hydrilla or Eurasian watermilfoil can grow and spread rapidly in a new location, and invasive snails or mussel larvae, often too tiny to see, can survive in small amounts of water in bait buckets or bilges until they find a new home.
It's easy to think that it's fine to dump leftover bait into the water when you're done fishing on your yacht, but when they're released, baitfish like baitfish like golden shiners or goby species can displace native species, spread disease, and disrupt the food chain. The water in your bait bucket can also be a problem, carrying pathogens or parasites.
The "Clean, Drain, Dry" method is a simple, effective practice adopted nationwide by environmental and boating organizations to prevent the spread of AIS. Every boater should make this a routine:
Most public boat launches will have boat wash stations, and if you have a small vessel, it's important to use them every time you take your boat out, especially if you move your boat between different bodies of water. Yachts should also be cleaned regularly to remove any organisms attached to the hull.
Being able to identify common AIS can help you take quick action. Here are a few particularly threatening species to look out for: