African Clawed Frog (Xenopus laevis) Risk Assessment, Strategic Plan, and Past Management for Washington State Department of Fish and Wildlife

Category: Aquatic Invasive Species

Published: 2021

Pages: 43

Author(s): Reed Ojala-Barbour, Richard Visser, Timothy Quinn, and Max Lambert

Executive Summary

African Clawed Frog (Xenopus laevis; ACF) occur in at least three disparate locations across the Puget Sound region. Repeated introductions by people, rather than dispersal among these locations, is the most likely explanation for these occurrences. Such repeated introductions may also be more widespread than is currently understood and, as such, future introductions are likely. ACF are voracious predators and vectors of novel pathogens and so pose a risk to native species through direct predation, competition, and disease. Here, we compile information about known ACF introductions, attempted control methods, and potential risks from ACF. We also outline knowledge gaps that are essential for research to address for risk assessment and mitigation. Unsuccessful prior management efforts and a lack of resources underscore the challenges of managing ACF in Washington State and the need for continued research. Without continued commitment from the agency, long-standing partnerships, particularly with local jurisdictions, that support ACF containment in Lacey are tenuous.

Purposeful management of ACF can only happen with an informed risk assessment. Such a risk assessment would ideally happen early in a species’ invasion which ACF in Washington presumably are, although data on the extent and timing of their introduction and spread are sparse. To inform a risk assessment, we propose prioritized ideal next steps in ACF management that vary in effort and investment. These include support to maintain and build partnerships that are essential to ACF management and validation of environmental DNA (eDNA) as an important tool to rapidly and affordably monitor ACF spread. This proposal also includes multiple research efforts that would provide the necessary data to inform a risk assessment and ACF management plan. These efforts include surveying to document the true extent of current ACF populations and associated spread and the studies necessary to assess the efficacy of various control methods. Depauperate data on ACF in Washington preclude informed risk assessment and management. When we better define elements of risk, we will collectively understand tradeoffs between future management scenarios, their chance of success, and their costs.