A risk assessment for managing non-native parasites

Abstract

The spread of non-native parasites with the movement of animals is a primary cause of disease emergence worldwide. Such introductions can threaten native biodiversity, hinder conservation efforts and limit the socio-economic development of natural resources. Evaluating the threats from alien parasites can represent a considerable challenge, due to the limited information that often accompanies their introduction. We present a comprehensive modular risk assessment scheme that supports the management of non-native fish parasites in their pre- and post-introduction phases. This scheme addresses some of the shortcomings of current risk analysis, including the risk management of non-notifiable pathogens and impact assessment of parasites following establishment. An initial procedure for hazard identification promotes a rapid assessment of disease risk and prompt imposition of management measures. This is followed by a longer-term assessment of impact that accommodates available and emerging knowledge on the pathogen and its distribution. Consideration is given to ecological and economic consequences of disease at the host, population and fishery levels. Each module provides an easily interpreted output that underpins management responses, ranging from monitoring parasite distribution to their attempted eradication. A final module ensures clear communication of disease risk to relevant stakeholders, using the other modules as a framework. Outputs of this risk assessment will inform the prioritisation of available resources and provides a scientifically robust foundation on which to base practical and proportionate management measures to protect native environments. The scheme presented here was specifically developed for freshwater fisheries in England and Wales, but may be modified for use globally and for the non-native parasite fauna of other taxa.