Observation of Red Swamp Crayfish (Procambarus clarkii) Feeding Upon Giant Salvinia (Salvinia molesta)

Abstract

Salvinia molesta (Giant Salvinia) is a highly problematic, non-native, invasive species in the southeastern United States. Other than introduced biological control agents, observations of natural enemies to Giant Salvinia are rare within the United States. We observed a native crayfish, Procambarus clarkii (Red Swamp Crayfish), feeding on Giant Salvinia in outdoor ponds that are typically utilized for mass-rearing Cyrtobagous salviniae (Salvinia Weevil), a Giant Salvinia biological control agent. Red Swamp Crayfish consumed the roots and leaves of Giant Salvinia, which greatly reduced its biomass. To our knowledge this is the first documented observation of the Red Swamp Crayfish consuming Giant Salvinia. This observation increases our knowledge about species that can consume Giant Salvinia and is a potential new pest of concern for managers of Salvinia Weevil rearing operations.