Research ProjectNational Exotic Marine and Estuarine Species Information System


Project Goal

We collate published and unpublished data to document the occurrence, distribution, ecology and impacts of non-native marine and estuarine species in North America. This information is made publicly available through the NEMESIS website (link below).


Globalization connects us like never before. Just as people and goods are moving freely between continents, so too are marine species. Introduced species are moved across oceans and water bodies primarily by hitchhiking on commercial ships, recreational boats, and aquaculture or aquarium shipments. Understanding the distribution of arriving non-native species, including where, when and how they are moving, is essential for protecting native ecosystems. To address this, the Marine Invasions Research Lab created the National Exotic Marine and Estuarine Species Information System, or NEMESIS. 

NEMESIS provides comprehensive information on the distribution of nearly 500 non-native plants, fish, invertebrates, protists and algae that have established populations in the marine and estuarine waters of North America. The database includes information on when, where and how species were introduced, as well as their global (native and non-native) distribution. It also summarizes key information on the biology, ecology, and known impacts of each invader. 

Information on species across the U.S. is available on the national NEMESIS database. Portals specifically for California and the Chesapeake Bay have also been created. The development of NEMESIS has involved years of research and literature review, and remains an ongoing project. Species records are continually updated as new occurrences are reported and new research is available.  

Feature Stories

Spaghetti’s on the Menu in the Galapagos. By Linda McCann and Monaca Noble. October 1, 2015

Unwanted Species: The Fouling Community. By Monaca Noble. July 1, 2012.

How much do we know about the impacts of invasive species? By Monaca Noble. September 1, 2011

Cryptogenic Species: Using History and Genetics to Solve Invasion Mysteries. By Monaca Noble. April 1, 2011

Adapt: From the Dock to the Mudflat. By Monaca Noble and Chela Zabin. February 1, 2011


Tracy, Brianna M., Larson, Kristen J., Ashton, Gail V., Lambert, Gretchen, Chang, Andrew L. and Ruiz, Gregory M. (2017). Northward range expansion of three non-native ascidians on the west coast of North America. Bioinvasions Records, 6 (3) , 203-209.

Simkanin C, Fofonoff PW, Larson K, Lambert G, Dijkstra JA, Ruiz GM (2016) Spatial extent and temporal spread of Ascidian invasions in the continental United States and Alaska. Marine Biology 163: 1-16

Ruiz GM, Fofonoff PW, Steves BP, Carlton JT (2015) Invasion history and vector dynamics in coastal marine ecosystems: A North American perspective. Aquatic Ecosystem Health and Management 18: 299-311

Ruiz GM, Fofonoff PW, Steves B, Foss SF, Shiba SN (2011) Marine invasion history and vector analysis of California: a hotspot for western North America. Diversity and Distributions 17: 362–373

Ruiz GM, Freestone AL, Fofonoff PW, Simkanin C (2009) Habitat distribution and heterogeneity in marine invasion dynamics: The importance of hard substrate and artificial structure. In: Marine Hard Bottom Communities: patterns, dynamics, diversity and change (Ed.) Martin Wahl. Springer Series: Ecological Studies, Vol. 206.

Simkanin C, Davidson IC, Faulkner M, Sytsma M, Ruiz G (2009) Intra-coastal ballast water flux and the potential for secondary spread of non-native species on the U.S. West coast. Marine Pollution Bulletin. 58: 366-374.

Fofonoff PW, Ruiz GM, Steves B, Carlton JT (2003) In ships or on ships? Mechanisms of transfer and invasion for nonnative species to the coasts of North America. In: Ruiz GM, Carlton JT (eds) Invasive Species: Vector and Management Strategies. Island Press, Washington, D.C., pp 152-182


Paul Fofonoff