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Potential Steps in a Dreissenid Response

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An initial detection of dreissenids in a waterbody could trigger a proposed action, which could necessitate an emergency consultation process with one or more of the Services, and trigger an implementation of a state or provincial rapid response plan. Any waterbody could be a potential location for the proposed action, from free-flowing rivers and streams, to hydropower reservoirs, and isolated water bodies. Access to any waterbody is dependent on the road network to each waterbody, and the amount of development and access sites available. Shallow areas close to public use access sites, such as boat launches and marinas, are the most likely locations where both dreissenid detections and proposed actions would occur because of the likely pathway of introduction (watercraft) and reality that any control action would need to occur in somewhat shallow water based on the ability to cordon off a waterbody.

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Specific tasks associated with each action may include detection area isolation, sample collection, site monitoring, site preparation, fish and wildlife salvage, mussel treatment, equipment decontamination, site restoration activities associated with the control action (if necessary), and implementation of conservation and minimization measures and best management practices to avoid and minimize adverse environmental effects.

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The following describes the types of most likely treatments and activities that would likely occur upon a detection of dreissenids. Note that these steps may occur concurrently, not necessarily sequentially, and incorporate elements of an incident command system.

1. Initial Detection
and Notification

An initial detection of dreissenids requires immediate steps and additional testing validate the detection and define the scope and extent of the potential infestation.

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Communication relating to a dreissenid incident is either minimal, or extensive, based on the scope/complexity of the incident. The intent of any communication is to share the current and ongoing status of the incident. There are two essential types of communication—internal and external.​

Tow plankton sampling

Plankton tows can help determine the extent of a dreissenid infestation. Photo credit: Invasive Species Council of British Columbia.

  • Internal communication is driven by the lead action agency/entity, who determines the extent of communication within his/her organization to raise awareness and develop a shared understanding of the status of the incident.

  • External communication is driven by the lead action agency/entity, who conducts a conference call with those that have jurisdictional responsibility for response/action, those that could potentially assist with response, those that have signed onto the Declaration of Cooperation, and Endangered Species Act Section 7 Consultation Leads (if appropriate).

3. Activate Incident Management System

Activating the Incident Management System advances coordination, communication, and response to a dreissenid introduction.​Generally, the lead action agency (e.g., the state or provincial fish and wildlife agency) initiates the Incident Command System (ICS) upon official verification of a suspect detection of dreissenid mussels. The scope, scale and function of the ICS is determined based on the circumstances of the detection. The lead action agency may request assistance from other partners, which may result in cooperating agreements.

ICS checklist
  • A rapid response may result in containing the invasion to a given area, suppressing population densities to reduce the rate of spread, prohibiting high-risk transport vectors, or in the least desirable scenario, developing adaptive strategies to co-exist with the invader. Based on the evolving situation for new detections, the lead action agency sets the objectives for the response. There are key steps integral to any such effort, including:
     

(1) responding to and minimizing impacts of infestations;

(2) providing timely and accurate information to managers, stakeholders and the general public;

(3) providing for the safety of the public as well as all personnel involved at any stage of a response; and

(4) coordinating with neighboring and regional jurisdictions on immediate response and long-term management, as appropriate.

 

Developing a shared understanding of these important steps prior to a response is critical to effective prevention efforts, and greatly enhances the ability of jurisdictions to coordinate and cooperate.

5. Notifications and Communication

Communication is integral to any containment strategy because containment strategies can affect boaters, other jurisdictions or management authorities, communities near waterbodies, and numerous other entities.​

 

Sample Press Release

Sample Declaration of Emergency

Sample Executive Order

Communication
7. Evaluate Response Alternatives

Response to an introduction of dreissenids may lead to early detection rapid response actions, or containment and mitigation actions.

If an action is deemed feasible (see below for more details on each):

 

  • Incorporate Endangered Species Act Best Management Practices

  • Incorporate Section 7 Consultation Requirements (if appropriate)

  • Obtain all necessary permits to implement the action

  • Obtain and organize resources

  • Implement the action

  • Evaluate the response

Dreissenid response control options
9. Select Response Action

Select the response action that is most likely to achieve control/containment goals, is feasible to implement, and minimizes detrimental effects to native and listed species and designated critical habitats.

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When evaluating potential effects to native and listed species and habitats, consider how you define the geographic scope of your action, considering areas upstream and downstream of the project site. 

Options sign

Implementing best management practices is critical to minimizing detrimental effects to native and listed species and critical habitats as reducing the risk of introducing or spreading invasive species. 

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Consult with the Best Management Practices on this website, and explore the Nationwide Standard Conservation Measures

that should be implemented at all project sides to reduce impacts to birds and their habitats. These measures include practices focused on habitat protection and stressor management (vegetation removal, invasive species introduction, artificial lighting, collision, entrapment, noise, chemical contamination, and fire).  

2. Verification

Mussel veligers (i.e., free-floating microscopic larvae) are sampled pulling a fine-mesh (mesh size of not less than 64 ‎μm and not more than 65 μm) horizontal plankton tows (WRP 2018). Plankton tow samples are analyzed for veligers using both visual and molecular techniques. Settlers (i.e., juveniles) and adult mussels are sampled via substrate samplers and other direct observations, such as shoreline surveys and SCUBA diving. Water quality data (e.g., profile readings recorded in the

Lab verification

​field, water chemistry samples for laboratory analysis, etc.) can be collected to provide insight into aquatic habitat conditions.

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The Western Regional Panel and its member entities have adopted these guidelines for classifying water bodies for dreissenids (WRP 2018):​

 

  • Unsampled – Waterbody is not being sampled or monitored for dreissenids.

  • Undetected/Negative – Sampling/testing is ongoing and nothing has been detected, or nothing has been detected within the time frames for de-listing.

  • Inconclusive (temporary status) – Waterbody has not met the minimum criteria for detection.

  • Suspect – Waterbody has met the minimum criteria for detection.

  • Positive – Multiple (2 or more) subsequent sampling events that meet the minimum criteria for detection.

  • Infested – A waterbody that has an established (i.e., reproducing and recruiting) population of dreissenids.
     

The minimum criteria for detection is two independent lab results from the same sample using scientifically accepted techniques, such as cross-polarized microscopy, DNA-based polymerase chain reaction (PCR) assays, gene sequencing, and taxonomic identification.​

 

Dreissenid mussel laboratories​

 

For additional information about sampling and laboratory protocols as well as water body monitoring data in the West, visit here: https://www.westernais.org/monitoring

4. Delineate Geographic Scope

Delineating the geographic scope of the infestation helps inform the scope and potential impact of the infestation as well as any need for emergency restrictions. Delineating the scope and extent of the infestation requires intensive sampling efforts, which may include:
 

  • plankton tow sampling (microscopy analysis) and eDNA sampling in the infested area as well as upstream and downstream of the infestation;

Plankton tow in British Columbia

Plankton tows can help determine the extent of a dreissenid infestation. Photo credit: Invasive Species Council of British Columbia.

  • examination of existing substrate samplers throughout the region, with an emphasis on water delivery and other entities with associated hydropower infrastructure;

  • a suite of methods to examine and potentially remove infrastructure in which dreissenids may attach; and

  • enhanced communication with property owners in and around the perimeter of the infestation to secure permission for sampling efforts.

6. Containment

Preventing further spread through containment strategies focused on pathways of spread is foundational to any new detection of dreissenids, and may include mandatory inspections, decontaminations, or closures. When closure of the waterbody is not possible, well-equipped watercraft inspection and decontamination teams should be deployed to inspect and decontaminate watercraft pre-launch and post haul-out.

Watercraft decontamination sign
8. Determine if ESA Consultation is Triggered

Section 7 (a)(2) of the Endangered Species Act requires federal agencies to ensure that any action they authorize, fund, or implement is not likely to jeopardize the continued existence of any federally listed species, or result in the destruction of adverse modification of designated critical habitat.

When a federal agency determines that its action "may affect" a listed species or designated critical habitat, the agency is required to consult with the U.S. Fish and Wildlife Service and/or the
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National Marine Fisheries Service regarding the degree of impact and measures available to avoid or minimize adverse effects.

Even if a non-federal jurisdiction is leading a rapid response operation, an associated federal action may trigger Section 7 of the ESA, such as:

 

  • Actions on federal land

  • Actions that require a federal permit

  • Actions that require a federal license

  • Actions using federal funds

  • Actions implemented by federal agency employees

ESA process
10. Obtain and Organize Resources

Resources needed will depend on the response action that will be taken. There are many considerations when planning for a response, including, but not limited to:
 

  • Location and terrain of water body treatment areas (ingress and egress)

  • Personnel

  • Budget

Snorking figure
  • Availability of control chemicals/products in desired quantities

  • Availability of mussel-detection canines

  • Dive teams

  • Estimated turnaround time for laboratory samples

  • Number of users that extract/use water from the water body/system being treated

  • Existing communication networks

Best Management Practices graphic

© 2024 Pacific States Marine Fisheries Commission, U.S. Fish and Wildlife Service, U.S. Bureau of Reclamation

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