Eastern Sierra WID

Golden mussels are a new aquatic invasive species (to North America) and they pose an even greater risk to Mono County waters than quagga and zebra mussels.

While quagga and zebra mussels require relatively high calcium levels in the water to survive and reproduce, golden mussels can tolerate much lower calcium levels. And no, sadly, our cold temperatures and freezing lakes don’t stop them either.

Golden mussels:

• Attach to almost anything — docks, rocks, boats, motors, pipes, aquatic plants, even muddy lake bottoms
• Survive in a wide range of water temperatures and chemistry, including low-calcium waters like many Eastern Sierra lakes
• Can live outside of water for periods of time
• Reproduce rapidly, spawning multiple times per year and producing thousands of microscopic larvae (called veligers) that are nearly impossible to detect

Unlike quagga or zebra mussels, golden mussels are especially capable of surviving in Eastern Sierra conditions.

If introduced to the Eastern Sierra, golden mussels can:

• Permanently damage lake and stream ecosystems
• Deplete plankton that fish depend on for food
• Threaten recreational fishing, boating, and tourism 
• Clog docks, motors, water delivery systems and pipes
• Increase water and power costs due to expensive maintenance 

In October 2024, golden mussels were detected in the Port of Stockton. In less than one year, they spread more than 250 miles south.

Our lakes and rivers are highly interconnected. An introduction in one location could spread quickly across the region. Prevention is the only solution.

The entire process – inspection, decontamination, and the stickers (watercraft and trailer) – is free!

→ Resident watercraft (Mono or Inyo County): Inspected once per year before the first launch of the season.
→ Visiting watercraft : Inspected when entering Mono or Inyo County before launching.
→ Watercraft inspected in Inyo County: That inspection is valid in Mono County for the same month. This reciprocity is limited to Mono and Inyo Counties.
→ Watercraft inspected in Mono County: That inspection is valid in Inyo County for the same month. This reciprocity is limited to Mono and Inyo Counties.

→ Any watercraft that launches outside Mono or Inyo County: Must be inspected again before launching locally.

There is no charge for inspection, decontamination (if necessary), or the stickers (one for watercraft, one for trailer).

All trailered watercraft must be inspected before launching in Mono or Inyo County waters. This includes:

• Motorboats
• Jet skis
• Any watercraft transported on a trailer
• Float planes

From the ordinance: “Water vessel” means any trailered watercraft, or jet ski, or float plane capable of being launched into a water body within the County of Mono except as specifically exempted herein. Canoes, kayaks, car- top boats, float tubes, rafts, wind surfers/boards, boogey boards, nonmotorized paddle boats, and nonmotorized sail boats that are eight (8) feet or less in length are not considered water vessels for purposes of this article and are thereby exempt from the provisions herein.

Canoes, kayaks, paddleboards, float tubes, and rafts are generally not required to be inspected. However, all gear (including waders) must follow Clean, Drain, Dry practices, and inspections or decontamination are encouraged if you have any concerns.

Before entering any waterbody:

• Clean all boats and gear of visible plants and mud
• Drain all water from equipment
• Dry everything thoroughly

These steps help prevent the spread of invasive species and protect Eastern Sierra waters.

From the ordinance: “Water vessel” means any trailered watercraft, or jet ski, or float plane capable of being launched into a water body within the County of Mono except as specifically exempted herein. Canoes, kayaks, car- top boats, float tubes, rafts, wind surfers/boards, boogey boards, nonmotorized paddle boats, and nonmotorized sail boats that are eight (8) feet or less in length are not considered water vessels for purposes of this article and are thereby exempt from the provisions herein.

Inspection stickers help track when a watercraft was last checked and cleared to launch in Mono and Inyo County waters. The requirements differ slightly for residents and visitors:

Resident watercraft:

• Boats that stay in Mono or Inyo County for the season—whether owned by local residents or kept here through slip rentals, second homes, or extended stays.
• Inspected once per year before the first launch of the season
• Must be re-inspected any time the boat leaves Mono or Inyo County waters and returns
• Please bring proof of registration and/or proof of slip rental to your inspection

Visiting watercraft:

• Inspected upon entering Mono or Inyo County before launching
• Valid for the current month only within Mono and Inyo Counties
• Must be re-inspected if the boat leaves the area and returns—even within the same month

Additional notes:

• An inspection completed in Mono County is valid in Inyo County (and vice versa) for that same month
• Any watercraft that launches outside Mono or Inyo County must be inspected again before launching locally

Yes. Visiting boats must have a valid sticker for the current month. If your sticker expires, you’ll need a new inspection and sticker to continue launching—even if you haven’t left the area.

Inspection stickers are an important tool—but they only work if everyone follows the rules each time they launch. Aquatic invasive species are extremely difficult to detect and remove, and even one missed step can introduce them into our waters. Every inspection is an opportunity for prevention. We truly appreciate everyone doing their part to protect these lakes for the long term.

Mono County and regional partners are actively working to expand watercraft inspection options throughout the Eastern Sierra.

This includes developing an attestation process and working directly with local resorts and marinas to address watercraft that remain in the area, such as rentals and other boats that do not travel outside of Mono or Inyo Counties.

We are also working to secure funding, staffing, and logistics to support pop-up inspection sites in multiple communities, making it easier for residents and visitors to access inspection services.

This is a rapidly evolving effort, and we appreciate your patience as we continue to build and refine these programs to best protect our local waters.

An authorized inspector will:

• Ask a few questions about where your boat has recently been used
• Inspect your boat and trailer for water, mud, or invasive species

This includes checking areas like motors, bilge, livewells, ballast tanks, and any place water can collect.

Inspectors are checking to make sure your boat is:

• Clean (no plants, mud, or debris)
• Drained (no standing water)
• Dry (no moisture that could carry invasive species)

They are also assessing whether your boat has recently been in higher-risk waters.

Short answer: if your boat is wet, it will likely need decontamination.

We know that’s frustrating – especially if it’s just from rain or snow. But the reality is, we have no reliable way to tell the difference between water from weather and water from a recent launch.

Moisture is a problem either way. Even a small amount of standing water can allow invasive species to survive, and our job is to be absolutely sure your boat is clean before it launches.

If you can, letting your boat fully dry or using a cover ahead of time may help avoid decontamination. But if you arrive wet, please talk with staff—we’ll take a look and figure out the best path forward.

We know this isn’t always convenient. Thank you for working with us to get it right..

If your boat is clean, drained, and dry, and does not pose a risk, you will receive an Eastern Sierra Mussel Sticker and can launch.

If your boat is not clean, drained, and dry—or is considered high risk—you will be required to go through decontamination before launching.

Decontamination is a process performed by trained staff using high-temperature, high-pressure water to kill any invasive mussels or larvae.

This is required if:

• Your boat is not clean, drained, and dry, or
• Your boat was recently used in waters outside Mono or Inyo County

You can refuse an inspection, but your boat will not be allowed to launch, and doing so may result in a violation of local ordinance.

Inspection is typically quick (a few minutes). Decontamination may take longer depending on the size and condition of the vessel.

This is prohibited in Mono and Inyo Counties and helps prevent the spread of golden mussels and other invasive species.