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Introduction
Distribution information on nonindigenous aquatic species is generally widely scattered and difficult to find. Resource managers, scientists, policymakers, and even the public could benefit from accessibility of distribution, status, identification, and habitat information about nonindigenous species. When more information is accessible, better decisions can be made for managing or possibly eradicating nonindigenous species that are invasive or have the potential to become invasive. With that in mind, the focus of the Nonindigenous Aquatic Species (NAS) Database has been to document and verify these species known to have been introduced in the United States.
The northeast region of the US from Virginia to Maine, U.S. Fish and Wildlife Service Region 5, is important in terms of nonindigenous and invasive species. The following summary report provides an inventory of all known freshwater macrophytes that are present or have become established (i.e. naturalized) and marine and freshwater aquatic animals which may or may not be naturalized in New England and the Mid-Atlantic United States. Specific information has been compiled from the Nonindigenous Aquatic Species Database (http://nas.er.usgs.gov/), an online inventory developed for tracking aquatic introductions in the United States. Occurrence data is derived from monitoring programs, herbarium and museum voucher specimens, published accounts. and professional observations. In some cases species distribution is known only superficially due to significant gaps in collection and monitoring data. Increased efforts in the collection and provision of spatial data are needed at the local, regional, and national levels to permit more precise mapping of aquatic introductions.
This summary report is in the form of species profiles which contain information about identification, habitat, reproduction, distribution, impacts, and methods of introduction of each species found in the region. Aquatic macrophyte and animal distributions are mapped according to river drainage to relate locality data within natural drainage systems. River drainages are described by the U.S. Geological Survey’s (USGS) Hydrologic Unit Codes (HUC), a nested classification which identifies hydrologic regions at four levels in the United States. Maps herein employ the smallest drainage level (8-digit HUC) where the species has been either, naturalized, collected, or observed. Red stars (  ) on the map indicate the presence of a species within a state when locality information is not known. Green stars (  ) represent species presence within a particular area of a state, such as a county, when the drainage can not be determined. The US map highlights all states which have had a particular species introduced at some instance in time. Shaded areas on both maps do not necessarily imply occurrence throughout the drainage or state, but at a minimum, a collection or observation was made. The native ranges of these species are described in the text, not on the maps. The description of the Nonindigenous Range in each profile gives some details for locations in the New England and Mid-Atlantic region. For easier reading, information in the profiles is not cited. However, sources for information are listed in the Reference section at the end of this report.
The early settlers to North America knowingly introduced many plants and animals from Europe, Asia, and Africa to satisfy various agricultural, horticultural, and aquacultural needs. At the same time, many of these imported species were contaminated with non-target species. For example, before water was used for ballast, dry ballast aboard ships from Europe was dumped at American ports which contained a variety of contaminants including seeds of foreign plants. Since those early days until today, 250 species of aquatic animals and 30 species of aquatic plants having been introduced to this region. The most widely recognized methods of more recent freshwater introductions include the annual stocking of game fish, bait bucket introductions, manmade canals which have allowed the flow of organisms from one waterbody to another, nursery and water garden trade, and aquarium enthusiasts who discard animals and especially plants into open waters. In the marine and estuarine environments, ballast water and mariculture have been primarily responsible for introductions. All of these methods have led to the establishment of non-native species in the Mid-Atlantic and New England states.
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