Technical Information


Boat Design and Invasive Species

How a boat is designed can influence its ability to transport invasive species. Boats can be designed to:

  • Minimize colonization areas (cap areas)
  • Smooth areas
  • Through hull fittings
  • Improve drainage, venting
  • Reverse pumping

In a January 2015 summit with aquatic invasive species specialists and boat manufacturers, the specialists ranked the following by risk by transport:

  • Anchors/rode and lockers
  • Storage tanks (ballast, raw water, gray water)
  • Bilge water (deck drainage, compartmentalized)
  • Intake systems (strainers, seacocks, through hull fitting placement)
  • Live wells
  • Trim tabs
  • Generators
  • Air conditions
  • Boarding ladders

Drying Time Estimator for Zebra/Quagga Mussel Contaminated Boats


If a boat moved from an infested area will be launched in waters that are not infested with zebra or quagga mussels, the general recommendation is to keep the boat out of water and let it dry for a minimum of 30 days after cleaning all equipment and draining all possible sources of standing water. However, such "quarantine" times may be reduced depending on local temperatures and relative humidities.


In general, zebra and quagga mussels can survive longer out of water if local conditions are cold and humid than if conditions are hot and dry. This tool estimates recommended quarantine times based on average humidity and temperature zones in the 48 contiguous United States.


If a boat has been in infested waters, please use this tool to estimate the minimum time it should remain out of water (after being cleaned thoroughly), before launching in uninfested waters. Recommendations are only guidelines for average conditions and are based on evidence from laboratory experiments where other factors are held constant. Thus, recommended quarantine times may not produce 100% mortality under real-world conditions where unidentified, yet contributing factors are free to vary. This tool will provide a minimum quarantine time that you may need to adjust upward if your situation includes additional contributing factors that may be important.


Along with this tool, please use your best judgment before launching a potentially contaminated boat in uninfested waters.


Maximum Daily Temperature (°F)                                        Minimum Days Out of Water

                        <30 3="" p="">

                          30-40                                                                    28       (4 weeks)

                          40-60                                                                    21       (3 weeks)

                          60-80                                                                    14       (2 weeks)

                          80-100                                                                    7       (1 week)

                         >100                                                                         3   

Note: Add 7 days for temperatures ranging from 32 °F to 95 °F if relative humidity exceeds 50% (McMahon, pers. comm. 2009).



[1] Equation used to create the Drying Time Estimator:  is from U.S. Army Corps of Engineers Contract Report EL-93-1, June 1993, "Use of Emersion as a Zebra Mussel Control Method" by Robert F. McMahon, Thomas A. Ussery, and Michael Clarke, The University of Texas at Arlington.*


Boat Design and Construction Considerations


Boat manufacturers and promoting standards for boat design and construction to minimize the ability of watercraft to transport aquatic invasive species. Industry is developing standards and promoting the following best management practices*:


Design and Construction:

  • Improve visual and physical access to areas subject to inspection and decontamination
  • Design wells, and other areas, for optimum drainage
  • Consider implementing external flushing ports
  • Weld strakes and keels (specifically recommended to deter the attachment of invasive mussels)

Systems and Components:

  • Simplified flush inlet fittings
  • Marking through-hull fittings
  • Filtration devices


  • Include AIS supplements in owner’s manuals
  • Standardize connections (e.g. common garden hose)
  • Investigate integrated strainer/flushing technologies
  • Test engines to current decontamination procedures for adverse effects


  • Incorporate labeled AIS flush ports or openings
  • Add standardized hose fitting at flush opening (i.e. garden hose)
  • Where possible, avoid square edges. Rounded designs prevent corners that may trap organic materials.

*Extracted from the draft Boat Design and Construction in Consideration of Aquatic Invasive Species report by the American Boat and Yacht Council (March 2016).


Equipment Manuals

Inspection and Cleaning Manual for Equipment and Vehicles to Prevent the Spread of Invasive Species (Bureau of Reclamation 2012)


Research Papers