A decision support system for identifying potentially invasive and injurious freshwater fishes

Abstract

An increasing threat to U.S. waterways is the establishment and spread of invasive and injurious fishes. A species may be designated by the U.S. Fish and Wildlife Service (USFWS) as federally “injurious” under the Lacey Act (18 U.S.C. 42) either if that species causes harm (injury) without establishing and spreading (not invasive), or if that species causes harm after establishment and spread (invasive). Species designated as injurious are prohibited from being imported, which is a highly effective way of preventing invasions by nonnative species. We developed a decision-support, riskassessment system to aid USFWS’s prioritization of species for injuriousness. Our system is based on USFWS’s evaluation criteria of a species’ potential injuriousness and consists of a semi-quantitative, rapid-assessment procedure called the Ecological Risk Screening Summary (ERSS) and a quantitative probability network model called the Freshwater Fish Injurious Species Risk Assessment Model (FISRAM). ERSS provides information on a species’ history of invasiveness elsewhere in the world, and on its biology and ecology, potential or known effects of introduction, global and domestic distribution, and climate associations, and provides conclusions on potential risk of invasiveness. FISRAM calculates expected probability of injuriousness as a function of species potential establishment, spread, and harm, based on probable effects on native species and ecosystems, suitability of climate and habitat in introduced areas, ease of dispersal and transport, and harm to humans. FISRAM is used to assess risk probability when ERSS categorizes invasion risk as uncertain. We calibrated and updated the probability structure of FISRAM using a data set of 50 species with known invasiveness outcomes. We demonstrate the use of these two models for risk assessment and decision-support in identifying and documenting species for potential risk management actions, such as listing wildlife as injurious under the Lacey Act.