Can zebra mussels be eradicated once they have entered a lake?

Please note that I am not a biologist, so be sure to do your own research. This is a summary of my personal research.

In order to better understand the phenomenon of zebra mussels, I met with and interviewed a few biologist friends who have expertise in invasive species. My main question was whether it is possible to eradicate zebra mussels from a body of water.

The answer is clear: it is unlikely! In fact, zebra mussels reproduce exponentially fast. A female produces 1 million eggs per season with a survival rate of 10%. It is possible that future technologies will make it possible to eradicate them without impacting the ecosystem, but this is not yet the case.

Zebra mussels usually help to clarify the water as they are excellent filter feeders. Simply put, clearer water allows more sunlight to pass through, which promotes the growth of algae, some of which can be toxic. This disrupts the ecosystem and replaces native species in the water.

Not to mention that zebra mussels cause economic problems such as clogging facilities such as pumping stations.

Here are some examples of water bodies that have been invaded by zebra mussels (provided by chatgpt):

Lake Michigan (United States)

After the invasion of zebra mussels in the 1980s, water transparency doubled on average.
Mussels filter approximately 1 billion liters of water per day in this lake.
This allowed more light to reach the bottom, promoting the growth of aquatic plants.

Lake Erie (United States/Canada)

Water clarity improved locally after the arrival of the mussels.
However, this clarity has also encouraged the proliferation of toxic algae such as Microcystis, which produce toxins that are harmful to humans and animals.

As you know, I like to ask ChatGPT what it knows. I asked it if it believes that zebra mussels can be eradicated from a body of water. We can only reduce their impact.

Here is his response:

In short: no, it is not possible to completely eradicate zebra mussels once they have established themselves in a natural water body. However, it is possible to limit their spread and reduce their impact.

1 adult female lays up to 1 million eggs per year.
Approximately 1% survive to adulthood.
Mussels reach maturity in one year.
They live for about 3 to 5 years.

In five years, the population could theoretically grow from 10 individuals to more than 1.4 billion.

In reality, factors such as food, space, predators, and human actions slow growth, but the invasive potential is enormous. This is what makes zebra mussels a feared environmental scourge.

Growth over 5 years (with a small starting population)

Why is it so difficult to eradicate?

The zebra mussel (Dreissena polymorpha) is an extremely resilient invasive aquatic species with characteristics that make eradication nearly impossible:

It reproduces very quickly (up to one million eggs per female per year).
It can be securely attached to almost any surface (boats, rocks, infrastructure).
Its larvae (veliger) are microscopic and can move freely in the water.
It has no effective natural predators in the water bodies where it is invasive.

Are there any methods of eradication?

Here are the known methods, but they are limited and rarely effective on a large scale:

Chemicals (biocides, chlorines, etc.)

Used in controlled environments (e.g., industrial water systems).
Not suitable for lakes or rivers: too much damage to ecosystems.

Physical treatments (drainage, freezing, deoxygenation)

Effective in small enclosed bodies of water or water pipes.
Impossible to apply on a large scale (e.g., lakes, rivers).

Biological control (predators, parasites)

Experimental: certain fish or bacteria are being studied.
High risk of introducing other problematic species

What we can do realistically and usefully:

Preventing the spread

Wash boats, engines, trailers, kayaks, etc.
Empty and dry boats before changing waterways.
Public information campaigns

Mitigate impacts

Clean water intakes and infrastructure regularly
Protecting sensitive habitats
Monitor populations through monitoring programs

In summary:

Total eradication: virtually impossible once zebra mussels are well established in a natural water body.
Control, prevention, and damage reduction: the only viable approaches at present.

Obviously, all boats pose a risk of contamination when they are not washed. In fact, a zebra mussel can attach itself to a boat in just a few hours thanks to its byssal filaments (like tiny, very strong threads).

Despite the washing stations that strive to clean the boats, this is not foolproof, as many boats have live wells and ballast tanks. Live wells allow water to be pumped from the lake into a compartment of the boat to hold the fish that are caught, keeping them alive. Ballast tanks are huge water reservoirs that pump water into the boat to add weight and create a surf wave.

Wakesurf boats fill their ballast tanks with water before the surfing session. When the session is over, the boat pumps the water out of the boat to reduce its weight and allow it to return. A wakesurf boat can pump between 800 and 3,000 liters of water in less than 5 minutes.

Wakesurf boats that travel from one body of water to another make decontamination difficult because they absorb invasive species into their ballast tanks. Even though they pump the water out before leaving the lake, these species can remain in the tank and be returned to another body of water during the next surfing trip.

The same applies to fishermen’s fish tanks: they must be emptied into the same body of water and allowed to dry completely before pumping again and discharging the water into another body of water.

Ideally, washing stations should clean fish tanks and ballast tanks, which, for example, has never been done in the case of my fishing boat. Are wakesurf boats’ ballast tanks washed? I doubt it! In fact, people will need to be made aware of this if self-service washing stations are installed. They will have to wash their fish tanks and ballast tanks. Besides, can a ballast tank be washed? According to my research, it is feasible.

Here’s how to clean the ballast tanks of a wakesurf boat according to ChatGPT:

How to clean ballasts:

Drain completely

After each outing, empty all ballast tanks using the pump system.
Leave the tanks open (if possible) to air dry.

Rinse with fresh water

Si tu as un accès, fais circuler de l’eau douce propre à travers les ballasts pour les rincer.
Certains bateaux permettent ce type de rinçage via une prise d’eau dédiée.

Use a disinfectant solution (if necessary)

Mix water and white vinegar or a mild disinfectant solution (follow local recommendations).
Leave on for 10 to 20 minutes, then rinse thoroughly.
Never use overly aggressive products that could damage the pumps or seals.

Drying

Ideally, leave the boat dry for at least 5 days in a warm/sunny place. Larvae do not survive well when dried out.

Avoid

Never release ballast water into another lake or river without first draining and cleaning it: this is one of the main vectors for spreading invasive species.

Why are wakesurf boats problematic?

Wakesurf boats use a ballast system (water tanks) to add weight and create a big wave. Here’s the problem:

Water on board = contaminated water

The ballast is filled with water from the body of water where the boat is sailing.
This water may contain:
- Zebra mussel larvae (microscopic)
- Fragments of aquatic plants such as myriophyllum
- Other invasive microorganisms

Interlaced transport

When the boat is transported from one lake to another without completely emptying and disinfecting the ballast:
- He releases the species into a new body of water.
- And thus contributes to their introduction and spread.

Scientific support

Studies conducted in Quebec, Ontario, and the United States have shown that:

Ballast systems are very difficult to empty completely.
Zebra mussel larvae can survive for several days in wet ballast.
Some boats carry up to thousands of liters of contaminated water.

Concrete examples

The introduction of zebra mussels and Eurasian watermilfoil has been linked to the transport of boats between bodies of water, including those used for water sports such as wakesurfing.
Several watershed organizations and municipalities have tightened controls for these types of boats:
- Inspections
- Mandatory washing stations
- Restrictions on access to sensitive lakes

In October 2021, Quebec’s Ministry of Forests, Wildlife, and Parks “officially” announced the presence of zebra mussel larvae and juveniles in Lake Massawippi (north and south of the lake). According to several experts, zebra mussels were already present in Lake Massawippi before 2021.

In conclusion, once the zebra mussel is introduced into a body of water that has the conditions to promote its reproduction, it is almost impossible to eradicate it.

In fact, Lake Massawippi is a perfect place for zebra mussels to reproduce due to its high percentage of dissolved calcium and suitable pH level. This makes Lake Massawippi more vulnerable to the rapid reproduction of zebra mussels.

Moreover, dives carried out in March 2025 showed active, open, and responsive mussels, even under the ice, demonstrating an exceptional adaptation to Massawippi, Quebec.

In theory, zebra mussels cannot grow indefinitely due to limitations in food supply, predators, and disease. This phenomenon is called maximum stable capacity. In fact, zebra mussels compete with each other, which is a positive thing!

That said, there seems to be no miracle solution for eradicating zebra mussels, especially in Lake Massawippi. Let’s hope that the mussels get sick and disappear one day!