A preliminary investigation into biosecurity treatments to manage the invasive killer shrimp (Dikerogammarus villosus)

Following the detection of the invasive killer shrimp, Dikerogammarus villosus (Dv) at two sites in the UK in September 2010, an effective biosecurity system is required to prevent further spread. This study investigated the application of several treatments as potential biosecurity measures with a view to their application on Dv-infected fomites. For each treatment, adult Dv were submerged for 15 minutes at different concentrations to determine the maximum lethal concentration, and for each effective treatment for different times to assess a minimal lethal time (LT 50 ). Sodium hypochlorite (50,000 mg/Lmg/L), FAM30 (R) (6 m1/1), Virkon S (R) (1% solution) and water at high temperature (45 degrees C) were found to cause 100% mortality within 15-min exposure, while carbonated water caused narcosis in 100% of animals within a few seconds of exposure. Due to various drawbacks in the use of sodium hypochlorite, FAM30 (R) and Virkon S (R) (e.g. health and safety, legal use) they were not recommended as biosecurity treatments, whereas both water at high temperature and carbonated water showed promise. However, further investigation and field based research are required before these techniques can be fully realised as methods of control.