Better biosecurity: Spread-prevention of the invasive asian clam, corbicula fluminea (müller, 1774)

Abstract

Aquatic invasive species (AIS) negatively impact freshwater ecosystems on a global scale. As management options for control and eradication of established AIS populations are often complex, costly and resource-intensive, spread-prevention protocols are considered essential. The Asian clam, Corbicula fluminea (Müller, 1774), is considered a high-impact successful invader that can adversely alter freshwater habitats, community dynamics and ecosystem function. Accordingly, we examine the efficacy of a range of biosecurity techniques, including recommended (aquatic disinfectants, bleach and salt solutions) and more novel (hot water and direct steam) approaches, to induce adult C. fluminea mortality. In separate experiments, C. fluminea were submerged at 12 °C for up to 80 minutes in: 1) 2% and 4% solutions of Virasure® Aquatic and Virkon® Aquatic; 2) warm (30 °C) 2% and 4% solutions of these disinfectants; and 3) 10% and 20% bleach solutions. Furthermore, specimens were exposed to: 4) 30% and 70% salt solutions (NaCl) for up to 72 hrs; 5) hot water (35, 40 and 45 °C) for up to 20 minutes; and 6), direct steam exposure for up to 10 minutes. Adult C. fluminea were found to be largely resistant to aquatic disinfectants, bleach and salt solutions, with ≤ 58% mortality achieved at the maximum exposure times. However, immersion in hot water (≥ 45 °C) and direct steam exposure for five minutes and 30 seconds, respectively, rapidly caused mortality. Accordingly, simple biosecurity protocols that cause thermal shock appear highly effective. We discuss the need for further examination of biosecurity protocols across all life stages of current, emerging and potential AIS, and provide guidance for improving biosecurity practices.