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The information on this website under the Phase 1 menu tab incorporates information compiled from the first phase of a four-phase project to produce a risk analysis to assess the potential to spread aquatic invasive species via seaplanes. At the conclusion of the project, recommendations will be made to enhance U.S. aquatic invasive species-seaplane prevention efforts. The DRAFT material posted in the Phase I section of the website represents a compilation of material from numerous sources, some of which may ultimately inform the risk analysis. The purpose of compiling this information was to better understand the seaplane pathway and identify key data gaps and information needed to inform the risk analysis. No analysis of this information has been conducted to date as content is refined and additional sources and content are added.

Alaska Case Study

Map illustrating the locations of seaplane bases and Elodea infestations.
An individual handling Elodea from the float of a seaplane

Figure 1. Map (left) illustrates the locations of seaplane bases (red and white airplanes) and Elodea infestations near Anchorage, Alaska (Source: The green and yellow colors designate Elodea spp. populations (yellow indicates high concentrations of Elodea spp., and green indicates low concentrations). Photo shows Elodea spp. in Alexander Lake, Alaska (Source: Kristine Dunker, Alaska Department of Fish and Game). Proximity of seaplane bases to Elodea spp. populations in Alaska has precipitated interest in assessing the risk of the seaplane pathway and proposing proactive measures to mitigate that risk.

Preliminary studies of the seaplane transportation pathway in Alaska concluded that seaplanes have contributed to the spread of common waterweed (Elodea spp.), an herbaceous perennial aquatic plant (Figure 1) (Schwoerer 2017). Elodea spp. was first detected in 1982 in Eyak Lake in Cordova (Professional Fisheries Consultants 1985) and was subsequently discovered in 2010 in the Chena Lakes and Badger Slough (Carey et al. 2016). In 2014, Elodea spp. was detected in Alexander Lake in the Matanuska-Susitna Basin and has since been detected in numerous remote Alaska water bodies accessible only in the summer by boat or floatplane (Alaska Public Media 2014). In 2015, Elodea spp. was detected in Lake Hood, the world’s busiest seaplane base (Hollander 2015). In 2017, Elodea spp. was detected on Sports Lake on the Kenai Peninsula, likely the result of one of five private floatplanes on the lake (Schwoerer and Morton 2018). Currently, half of existing Elodea spp. populations are in floatplane-accessible water bodies (Larsen et al. 2020). Known Elodea spp. populations are believed to be the results of independent introductions followed by dispersal by floatplane and other pathways (Schwoerer and Morton 2018).

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