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This map was created to help assess impacts on nonindigenous aquatic species distributions due to flooding associated with Hurricane Maria. Storm surge and flood events can assist expansion and distribution of nonindigenous aquatic species through connection of adjacent watersheds, backflow of water upstream of impoundments, increased downstream flow, and/or creation of freshwater bridges along coastal regions. This map will help natural resource managers determine potential new locations for individual species, or to develop a watchlist of potential new species within a watershed.

The area of interest was defined using USGS WaterWatch data on flood and high flow conditions. The areas with stream gages or storm tide sensors at flood stage were selected.

The map was created by using known locations of established or possibly established species. All surrounding hydrologic units (HUCs at the 8 digit level) were selected as potential areas of infestation. We are searching for comprehensive flood data to refine the potential areas to drainages that actually became connected.

To view the current and potential distributions within the region affected by Hurricane Maria, select a species of interest from the list on the left. Watersheds with currently established populations are colored in light green, and watersheds with the potential for new introductions (defined as those adjacent to currently established watersheds) due to flooding impacts are colored in darker green.

To view lists of currently established and potential species within a watershed, click within the outline of the watershed of interest. Selecting a species from either of these lists will display its current and potential distribution within the region.

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

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Page Contact Information: Pam Fuller - NAS Program (
Page Last Modified: Thursday, November 09, 2017


The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2017]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [11/18/2017].

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