Fish and Aquatic Conservation


Ecological Risk Screening Summaries (ERSS)

The 2008 to 2012 National Invasive Species Management Plan called for the development of risk screening processes to evaluate the invasiveness of terrestrial and aquatic nonnative wildlife moving in trade. The Service developed ecological risk screening in response to this charge and has conducted an initial scan of tens of thousands of species, including 33,500 fish species from Fishbase alone. Based on evidence and expert opinion, the Service utilized history of invasion and anticipated harm to select approximately 1,725 species from the initial scan for further risk assessment through Ecological Risk Screening Summaries (ERSSs). Species posing broad risks to the United States were prioritized over species with expected localized or regional impacts.

The Service developed the ERSSs efficiently by using international databases, scientific literature, and a climate model. The climate model matches the basic climate requirements (temperature and precipitation) of a species in its native and known invasive ranges with similar climates in the United States to assess risk of establishment. The result provides an approximate geographic range in the United States where the climate is similar to where the species survives elsewhere; this is referred to as the species’ “climate match.” The Service has developed and peer reviewed a climate-matching program called the Risk Assessment Mapping Program or RAMP3 to conduct these climate matches.

We also obtain information on where the species has spread to other parts of the world outside of its native range and if it has established and caused harm there. We obtain information on what harm the species causes outside of its native range, such as the ability to outcompete native animals for food and rearing habitat, impacts to water quality, or the ability to spread pathogens that cause disease. We call this the species’ “history of invasiveness.”

Finally, we look at how certain we are that the information used for the climate match and history of invasiveness is scientifically credible, reliable, and of sufficient quantity to be used for the intended purpose. High certainty means that we are using scientifically credible and defensible information, data, and associated syntheses to draw clear and convincing conclusions about the species’ history of invasiveness and climate match with the United States. Medium certainty means that there is a preponderance of evidence relating to the history of invasiveness and the species climate match with the United States, and that the certainty of the assessment is neither high nor low. Low certainty means that limited or no information is available about the species for either variable. We call this “certainty of assessment” for the variables of history of invasiveness and climate match and is not considered in the Overall Risk Assessment.

The climate match in the United States and the history of invasiveness are combined to calculate the Overall Risk Assessment (which we sometimes refer to as simply “risk”). The risk categories are high, low, and uncertain. Please see the Standard Operating Procedures (SOP) for how each risk category is determined.

The “Standard Operating Procedures [SOP] for the Rapid Screening of Species’ Risk of Establishment and Impact in the United States” document was prepared by the Service and is intended to explain the purpose of the ERSS process and provide rigorous, repeatable steps necessary to obtain the species data to complete a risk assessment. Key goals of this specific SOP are to standardize data collection and interpretation of risk assessments and to assure the credibility of resulting reports for transparency and repeatability.

The public is encouraged to use the following email address to submit information on the ERSS reports that might help to improve the accuracy of the assessment: prevent_invasives@fws.gov

The Service uses these ERSSs in two ways:

  1. To provide information to the public: The ERSSs are available to the public so that any government, industry, or other stakeholder that may be considering trading, transporting, or owning a particular species can use the information we have gathered and assessed to make a more informed decision. Each jurisdiction or entity can decide what level of risk it is willing to accept and if the ERSS provides adequate information for their purposes. Hobbyists can also use this information to make decisions appropriate to their own situation and make more environmentally responsible choices regarding pet ownership. For example, State natural resource and conservation agencies can use the ERSSs to aid in their management decisions for potentially invasive species and work directly with industry to develop their own agreements for species trade in their jurisdictions. Additionally, species characterized as uncertain risk in ERSSs can identify which species may need additional assessments before informed decisions can be made on where, how, and when a species is utilized.
  2. As an initial step toward selection and evaluation by the Service for considering species to list as injurious: The Service may select species with a “high” overall risk assessment result from the ERSSs for more detailed evaluations to determine if a proposal for listing as injurious wildlife is appropriate. We emphasize that the Service does not list species based solely on the ERSSs and that further more in-depth reviews are completed on species being evaluated for a proposed injurious wildlife listing. Please see “Injurious Wildlife Evaluation Process Flow Chart” for the general process the Service uses to prepare an injurious listing and “Injurious Wildlife Listing Criteria” for the factors that contribute to or reduce the likelihood of the species being considered injurious. We generally seek public comment by publishing a proposed rule in the Federal Register. We also seek peer review and post a peer review plan on the Service’s public website. A summary of the comments and our responses on the proposed rule is published in the Federal Register along with the final rule.

Availability of Ecological Risk Screening Summaries

The aquatic based ERSSs will be posted on this site as they are finalized. Because categorizing ecological risk is based on the current understanding of ecological conditions and species preferences, new information could change the ERSS results. Therefore, please check the ERSS website periodically to obtain the most current information.

Ecological Risk Screening Summary Reports