Responsible Recreation Helps Reduce the Spread of Aquatic Invasive Species

Outdoor recreation is a great summer hobby in Pennsylvania! With just a few simple steps, we can work to prevent the spread of aquatic invasive species while enjoying our favorite outdoor activities.

As we gear up for Labor Day celebrations on our beloved lakes and rivers, it's essential to remember the importance of protecting our aquatic ecosystems. While squeezing every drop out of a Pennsylvania summer with fall on the horizon, the threat of aquatic invasive species (AIS) lurks beneath the surface. These non-native species pose a significant risk to the health and balance of our waterways, disrupting native ecosystems and costing millions in control efforts each year.

AIS come in many forms, from zebra mussels to invasive plants like hydrilla. They often hitchhike on boats, trailers, and recreational equipment, spreading rapidly from one body of water to another. With increased boating and water recreation activities during the holiday weekend, the risk of inadvertently introducing or spreading AIS is heightened.

Zebra Mussels (Dreissena polymorpha)

Zebra mussels are fingernail-sized freshwater mollusks that attach to objects and other organisms. Since their discovery in the Great Lakes, they have quickly spread to become one of the most intrusive, prolific, and costly aquatic invaders in North America. Efficient filter feeders, zebra mussels are capable of filtering one liter of water per day, consuming microscopic plants and animals, called plankton. The removal of plankton, in turn, reduces the amount of food available for other organisms. Research has shown this disruption in plankton availability has impacted the growth of sport fish species like walleye. Zebra mussels also selectively filter feed on certain types of green and brown algae, while rejecting toxic cyanobacteria. This results in higher concentrations of cyanobacteria in the algal community, which can cause taste and odor problems for drinking water supplies and lead to harmful algal blooms. Filtering of the water also allows sunlight to penetrate deeper into the water column, causing an overgrowth of aquatic plants. Native species of mussels and clams are also impacted as invasive mussels form colonies on their shells, hindering their ability to feed and breathe.

Zebra mussels attach themselves in large clumps on hard surfaces such as boat hulls, docks, and buoys. They can also colonize inside water intake pipes, clogging and damaging infrastructure at waterside industries such as power and water facilities. Removing and controlling mussels is very expensive, with the economic impact of zebra mussels in the United States and Canada reaching about $140 million dollars each year in damage and control costs.

For more information about zebra mussels, see the Zebra and Quagga Mussel Fact Sheet from Pennsylvania Sea Grant.

Hydrilla (Hydrilla verticillata)

Hydrilla is a submerged, aquatic, perennial plant that grows and spreads at a very fast rate covering the surface of water bodies and restricting boating, fishing, swimming, and other recreational uses. Hydrilla is a federally listed noxious weed, and so it is illegal to possess, distribute, or transport Hydrilla in the United States. In Pennsylvania, Hydrilla was first reported in the mid-1990s in Adams and Bradford counties and has since been identified in at least 25 counties spanning the entire state. Hydrilla reproduces primarily vegetatively meaning that even the smallest living plant fragment can float downstream and form a new infestation. This makes it easy for pieces of hydrilla stuck on boat motors, trailers, live wells, or bait buckets to start new infestations. Tubers are also a key component of reproduction and spread as they can remain dormant in the sediment for several years before growing new plants.

This invasive plant is characterized by its ability to grow quickly and form dense thick mats at the water’s surface that prevent sunlight from penetrating into the water and effectively shade out other species growing beneath. As the mats die and decay, bacteria deplete oxygen from the water. Hydrilla can also displace native plant life and shift balanced ecosystems to monocultures, which can alter populations of native fish and other wildlife.

Hydrilla interferes with both commercial and recreational freshwater activities and can have an expensive impact. Thick mats can hinder agricultural and hydroelectric power production by reducing irrigation flow rates by up to 90 percent and by clogging water intake pipes and filters. Hydrilla impairs recreational activities like swimming, fishing, water skiing, and boating. Heavy growth can entangle and clog propellers, requiring frequent cleanings to travel even short distances.

For more information about hydrilla, see the Hydrilla Fact Sheet from Pennsylvania Sea Grant.

Take Action

So, what can we do to enjoy our outdoor hobbies while minimizing the threat to our waters? Here are some simple yet effective actions we can take:

Clean, Drain, and Dry

Before leaving the water, thoroughly inspect your boat, trailer, and gear for any signs of AIS. Remove any plants, animals, or mud, and drain all water from bilges, motors, and live wells. Allow equipment to dry completely or dry off with a towel, as many AIS can survive out of water for days or even weeks. Pay special attention to hard-to-reach areas such as propellers, anchors, and trailer rollers, where AIS can hide. Consider installing specialized equipment, such as screens and brushes, to prevent AIS from attaching to your boat.

Use Local Bait

Avoid transporting live bait between water bodies. If you must use live bait, purchase it from a local source near the water you'll be fishing in. This helps prevent the accidental introduction of AIS from one ecosystem to another. Crayfish are of particular concern, and it is unlawful to transport live crayfish in the state of Pennsylvania.

Dispose of Bait and Trash Properly

Don't dump unused bait or aquarium pets into the water. Dispose of them in designated areas on land. Similarly, ensure all trash, including fishing line and plastic bottles, is properly disposed of to prevent entanglement and pollution.

Educate Others

Spread awareness about the threat of AIS and the importance of prevention among your friends, family, and fellow water enthusiasts. Encourage others to adopt responsible boating practices and participate in AIS prevention programs. Fact sheets and other resources are available through Pennsylvania Sea Grant and the Penn State Water Resources Team.

Report Sightings

If you spot any suspicious species or signs of AIS, report them to the appropriate authorities immediately. Early detection is key to containing and eradicating invasive species before they become established. Report potential sightings by downloading the Pennsylvania AIS Field Guide app on Android or Apple devices, call 1-833-Invasiv; or access the Pennsylvania Fish and Boat Commission’s online reporting form.

By taking these proactive measures, we can all play a part in preserving the health and beauty of our waterways for future generations to enjoy. This Labor Day, let's celebrate responsibly and keep Pennsylvania waters free from the threat of aquatic invasive species. Together, we can make a difference in protecting the natural treasures that enrich our Pennsylvania heritage.