Enemy of Arizona anglers: aquatic invasive species
Some have hitchhiked from the Black and Caspian Seas. They clog boat engines, kill fish, and wreck a once dynamic food base. Aquatic invasive species have been spreading in Arizona.
Many anglers are blind to the attack. Without intervention, memories made by catching fish with friends and family could simply become dreams.
Yet there’s hope. Between the Arizona Game and Fish Department’s Aquatic Invasive Species Program and anglers abiding by preventative measures, we can keep high populations of game fish chasing lures for future generations.
Cleaning, draining and drying your boat and fishing gear is an effective measure to ensure aquatic invasive species don’t spread.
Now to some of these aquatic invasive species:
Quagga mussels
Want more time on the lake catching fish? Help stop the spread of these little critters that cling and clog and have the potential to filter the bottom of the food base from an entire reservoir. This disrupts the food web and creates less food for our native and sport fish. They also reject toxins such as cyanobacteria that are responsible for algae blooms which can cause skin and respiratory issues and make water unsafe to drink.
See how invasive mussels have completely altered the approach to sport-fishing in Lake Michigan.
Quagga mussels are a widely spread and prolific aquatic invasive species in Arizona. Originally from the Black and Caspian Seas, these two-shelled mollusks made their way to the Great Lakes on commercial ships, and then to Arizona by way of recreational watercraft. That’s about 7,000 miles for these mussels to travel.
Once established here, they began overtaking popular fishing lakes such as Lake Mead, Lake Powell and Lake Pleasant. Boats and engines can become completely clogged by these mussels, resulting in thousands of dollars in repair and less time on the lake catching fish. These mussels don’t just do damage to your engine either — they can create hazards by weighing down or even sinking buoys.
They are just one of many invasives to battle.
Eurasian watermilfoil

Eurasian watermilfoil underwater
In some households, plants are set on tables as centerpieces and shelves for show. In the realm of invasives, they’re not a harmless decoration.
Invasive plants can impact our fish. Eurasian watermilfoil is an invasive aquatic plant that is found in many parts of Arizona. It can grow up to 30 feet long and looks feathery underwater. It’s found in many parts of Arizona. Eurasian watermilfoil grows in thick mats, preventing boats from passing through. The plant can get twisted up on a propeller and make kayaking or canoeing difficult.
Other negative impacts occur when this plant blocks out native plants that fish use for habitat. Small fish may be able to hide in the dense mats, but the bigger fish cannot. This interferes with fish predation, reducing catchable sized fish. Thick mats of Eurasian watermilfoil will cause bait and tackle to get caught and snagged.
Many aquatic plants, including Eurasian watermilfoil, can be spread from just a single fragment. Prolific, determined and crafty, these pieces that break off can actually start new plants.
This is the challenge anglers face.
Algae

Didymo is one type of algae
Even one dead, belly-up fish can make an angler stop and sigh and wonder, “Why?”
Sometimes, those fish anglers see gasping for air are victims of toxic algae blooms.
The main culprits? Algae such as golden algae or didymo.
Golden algae is a single-celled organism that produces a toxin when it blooms. This toxin causes large-scale fish die-offs by suffocating fish and any other gilled organisms. Imagine this: A single drop of water can have up to 2,000 golden algae cells.
Didymo is another algae that looks smooth and slick but feels like wet wool and can completely cover riverbeds and lake bottoms. This can reduce spawning grounds and suffocate small organisms that fish rely on for food. Both of these algae types can affect fish populations and decrease angling opportunities.
Snails, plants, mussels, algae, crayfish, frogs, fish and diseases are all things that our Aquatic Invasive Species Program manages.
Anglers: There are solutions to stopping the spread of these invasives.
A call to action

Water at Lake Pleasant is typically crystal clear due in large part to quagga mussels filtering high amounts of the microscopic organisms (food base).
Fishing pictures stuck to scrapbooks and peppered on social media feeds could always showcase some combinations of sunsets, friends and cold drinks. But less and less someday, without help from boaters and anglers, those pictures may not include the memory of a freshly caught sport fish.
Most people don’t intentionally introduce aquatic invasive species. Yet it happens.
Our Aquatic Invasive Species Program needs your help.
Many aquatic invasive species can survive in small amounts of standing water for relatively long periods of time. That is why it is so important to “Clean, Drain and Dry” your boats and equipment:
Some other steps:
- Before using a boat at another water, we recommend leaving your boat and gear out of the water for seven consecutive days if it is May through September, and 18 consecutive days if it is November through April.
- If you plan to launch your boat at a different water and cannot meet recommended dry times, contact the Aquatic Invasive Species Program to see about having your boat inspection and, if necessary, decontaminated for FREE. Boats that have been on the water for 6 or more consecutive days are required to be inspected and decontaminated by authorized agents of the state.
- Additionally, inspect your waders, boots, tackle and any other gear such as lures with cracks that hold water, waders, fishing boots, bait containers and paddles all have the potential to spread invasive species. Clean off all plants, mud, sand and drain and dry all water.
See a list of AIS-infected waters.
On mussel-infested waters such as Lake Pleasant, anglers are still catching striped bass and dining at lake-side restaurants and sharing fish stories (true or not) with buddies. But the water is crystal clear, filtered by quagga mussels and void of a natural balance. Don’t let the mussels filter our fishing memories, too.
Small steps can be taken that will not hinder your fishing experience and will ensure healthy fish populations, tight lines and good memories for generations to come.
For more information, visit https://www.azgfd.com/ais/or call 623-236-7608.
AZGFD Aquatic Invasive Species intern Hunter Pauling contributed to this post