Leo Nico, Ph.D.
Ph.D., Zoology, University of Florida, 1991
Dissertation: Trophic Ecology of Piranhas (Characidae: Serrasalminae) from Savanna and Forest Regions in the Orinoco River Basin of Venezuela. (Committee Co-Chairs: Horst Schwassmann and Carter Gilbert)
M.S., Biology, Southern Illinois University, 1982
Thesis: Life History and Ecology of Orinoco Basin Annual Killifish. (Committee Chair: Jamie E. Thomerson)
B.A., Biology with Departmental Honors, Southern Illinois University, 1979
Leo Nico is a Research Fishery Biologist with the US Department of Interior and US Geological Survey (1993-present). The mission of his USGS research program is to conduct basic and applied research on invasive and other nonindigenous fishes. Over the course of his non-government and government career, Nico has conducted research throughout the USA and in other parts of the world, including Venezuela, Brazil, Ecuador (including the Galapagos), Southeast Asia (Thailand), and Micronesia (e.g., Guam, Palau). He has authored over 50 scientific and popular publications including two books on nonindigenous fishes and is one of the DOI’s authorities on nonindigenous fishes.
Nico is basically an ichthyologist by training and his research is diverse. Together with an assortment of US and foreign collaborators, he has conducted research and published widely on a variety of both invasive and native fishes, covering such topics as natural history, ecology, aquatic biology, taxonomy/systematics, biogeography, genetics, age and growth, risk assessments and ecological impacts of invasive fishes, geographic distribution and dispersal of invasive fishes, eradication of invasive fishes, among other fields. A few of the nonindigenous fishes that he has studied include Asian swamp eel (Synbranchidae), black carp (Cyprinidae), suckermouth armored catfishes (Loricariidae), and various cichlids (e.g., tilapia).
Nico is involved in various new projects--including collaborative research on parasites and introduction pathways of Asian swamp eel and an analysis and assessment of methods to eradicate invasive fish populations.
Leo Nico was born in Illinois and grew up in a small town in the southern part of the state. He received his BSc (1979) and MSc (1982) degrees in Biological Sciences from Southern Illinois University – Edwardsville. Upon completion of his MSc, Nico spent the next two years in Venezuela where he was affiliated with the University of the Llanos (UNELLEZ) and collaborated with professor Don Taphorn conducting research and field work on freshwater fishes. Following that hiatus, he was acceptted into the University of Florida – Department of Zoology – where he received his PhD in 1991. For his MSc and PhD research Nico conducted field work in South America and intermittently continued to travel and conduct research on freshwater fishes in the Neotropics – ultimately -- between 1980 and 2010 spending some 5+ years in that region of the world.
Science and Products
Invasive species threaten biodiversity around the world, especially on islands. USGS scientists are helping to identify fish species that have the greatest potential to invade the fresh waters of Microneisa.
In parts of Asia, wild-caught and aquaculture-reared swamp eels are widely consumed as food by humans and are a common source of human gnathostomiasis, a food-borne zoonosis caused by parasitic nematodes of the genus Gnathostoma spp. In humans, the larvae of these nematodes can cause tissue damage and, in some instances, death. Over the past two decades, many thousands of Asian swamp eels have...
Development of an Environmental Assessment and Eradication Plan to Remove Tilapia from Ponds and Wetlands in National Parks on the Island of Hawai’i
Mozambique tilapia, a highly invasive non-native fish of the family Cichlidae, were discovered in a wetland in Kaloko-Honokohau National Historical Park on the Big Island of Hawai'i. As the U.S. National Park Service works to restore the natural communities and functions of wetland ecosystems on the island, the eradication of the tilapia population is considered necessary to fully achieve...
Black carp have likely been present in the Mississippi River since the 1990s, but their current distribution and spread is not well understood. Genetics is helping to shed light on this species, including its diversity, the relatedness of wild and captive fish, and its introduction history.
Detection limits of quantitative and digital PCR assays and their influence in presence-absence surveys of environmental DNA
A set of universal guidelines is needed to determine the limit of detection (LOD) in PCR-based analyses of low concentration DNA. In particular, environmental DNA (eDNA) studies require sensitive and reliable methods to detect rare and cryptic species through shed genetic material in environmental samples. Current strategies for assessing...Hunter, Margaret; Dorazio, Robert M.; Butterfield, John S.; Meigs-Friend, Gaia; Nico, Leo; Ferrante, Jason A.
Evaluating the piscicide rotenone as an option for eradication of invasive Mozambique tilapia in a Hawaiian brackish-water wetland complex
Mozambique tilapia Oreochromis mossambicus were recently discovered in ‘Aimakapā Fishpond, a 12-hectare brackish-water wetland complex in Kaloko-Honokōhau National Historical Park, on the Island of Hawai’i. As a possible eradication method, we evaluated rotenone, a natural piscicide used in fish management and the active...Nico, Leo; Englund, Ronald A.; Jelks, Howard L.
Genetic analysis of invasive Asian Black Carp (Mylopharyngodon piceus) in the Mississippi River Basin: evidence for multiple introductions
Invasive Asian Black Carp (Mylopharyngodon piceus) have been present in USA aquaculture facilities since the 1980s and wild Black Carp have been found in the Mississippi River Basin since the early 1990s. This study characterizes the genetic diversity and relatedness of the Basin’s Black Carp and clarifies the introduction history. Analyses...Hunter, Margaret E.; Nico, Leo G.
One carp, two carp: are there more carp in the Wailoa River?
The February, 2015 issue of Hawaii Fishing News included the annual list of Hawai`i records for the largest fish of various species caught in the state. Among the new records was one for a 15-pound grass carp (Ctenopharyngodon idella) caught by Avery Berido in the Wailoa River at Hilo on September 13, 2013. A photograph taken by Mr. Berido of the...Mundy, Bruce C; Nico, Leo; Tagawa, Annette
Gnathostoma spinigerum in live Asian swamp eels (Monopterus spp.) from food markets and wild populations, United States
In Southeast Asia, swamp eels (Synbranchidae: Monopterus spp.) are a common source of human gnathostomiasis, a foodborne zoonosis caused by advanced third-stage larvae (AL3) of Gnathostoma spp. nematodes. Live Asian swamp eels are imported to US ethnic food markets, and wild populations exist in several states. To determine whether these eels are...Cole, Rebecca A.; Choudhury, Anindo; Nico, Leo G.; Griffin, Kathryn M.
Validation of eDNA surveillance sensitivity for detection of Asian carps in controlled and field experiments
In many North American rivers, populations of multiple species of non-native cyprinid fishes are present, including black carp (Mylpharyngodon piceus), grass carp (Ctenopharyngodon idella), bighead carp (Hypophthalmichthys nobilis), silver carp (Hypophthalmichthys molitrix), common carp (Cyprinus carpio), and goldfish (Carassius auratus). All six...Mahon, Andrew R.; Jerde, Christopher L.; Galaska, Matthew; Bergner, Jennifer L.; Chadderton, W. Lindsay; Lodge, David M.; Hunter, Margaret E.; Nico, Leo G.
Discovery of South American suckermouth armored catfishes (Loricariidae, Pterygoplichthys spp.) in the Santa Fe River drainage, Suwannee River basin, USA
We report on the occurrence of South American suckermouth armored catfishes (Loricariidae) in the Suwannee River basin, southeastern USA. Over the past few years (2009-2012), loricariid catfishes have been observed at various sites in the Santa Fe River drainage, a major tributary of the Suwannee in the state of Florida. Similar to other...Nico, Leo G.; Butt, Peter L.; Johnston, Gerald R.; Jelks, Howard L.; Kail, Matthew; Walsh, Stephen J.
Eastern mosquitofish resists invasion by nonindigenous poeciliids through agonistic behaviors
Florida is a hotspot for nonindigenous fishes with over 30 species established, although few of these are small-bodied species. One hypothesis for this pattern is that biotic resistance of native species is reducing the success of small-bodied, introduced fishes. The eastern mosquitofish Gambusia holbrooki is common in many freshwater habitats in...Thompson, Kevin A.; Hill, Jeffrey E.; Nico, Leo G.
Use of stable isotopes and mercury to assess trophic positions of black carp and other large fishes in the Red-Atchafalaya River system, Louisiana, USAChapman, D.C.; Hoff, M.H.; Nico, L.; Demopoulos, A.; Gualtieri, D.; Wieser, C.
Salinity tolerance of non-native suckermouth armoured catfish (Loricariidae: Pterygoplichthys) in south-eastern Mexico: implications for invasion and dispersal
1. Salinity tolerance is one of several important physiological attributes that determine invasion success and the pattern of dispersal of introduced aquatic organisms. Introduced freshwater fishes able to tolerate elevated salinities have the potential to invade and exploit brackish-water (mixohaline) environments and use estuaries and coastal...Capps, Krista A.; Nico, Leo G.; Mendoza-Carranza, Manuel; Arevalo-Frias, Wendi; Ropicki, Andrew J.; Heilpern, Sebastian A.; Rodiles-Hernandez, Rocio
Imported Asian swamp eels (Synbranchidae: Monopterus) in North American live food markets: Potential vectors of non-native parasites
Since the 1990s, possibly earlier, large numbers of Asian swamp eels (Synbranchidae: Monopterus spp.), some wild-caught, have been imported live from various countries in Asia and sold in ethnic food markets in cities throughout the USA and parts of Canada. Such markets are the likely introduction pathway of some, perhaps most, of the five known...Nico, Leo G.; Sharp, Paul; Collins, Timothy M.