Action: Ponto-Caspian gammarids: Exposure to parasites
Key messagesRead our guidance on Key messages before continuing
- A replicated, laboratory study in Canada found that an introduced parasitic mould reduced populations of an invasive shrimp.
Parasites have the potential to control gammarid populations by reducing production of offspring, increasing risk of predation, slowing growth rates or causing death. In the wild, parasite infections have been associated with rapid die-offs of natural populations of freshwater shrimps, with the invasive species being more vulnerable than native species (Kestrup et al. 2011).
Kestrup A.M., Thomas S.H., van Rensburg K., Ricciardi A. & Duffy M.A. (2011) Differential infection of exotic and native freshwater amphipods by a parasitic water mould in the St. Lawrence River. Biological Invasions, 13, 769-779.
Supporting evidence from individual studies
A replicated, controlled laboratory study in 2011 in Canada (Kestrup et al. 2011) found that a parasitic water mould (oomycete) of unknown origin infected and killed invasive gammarids Echinogammarus ischnus. Invasive shrimps exposed to water carrying the mould had a 52% mortality rate after seven days, compared with 16% mortality in native shrimps. Laboratory tests used 20 replicate aquaria each containing 10 invasive and 10 native (Gammarus faciatus) shrimps. Two litres of river water was placed in each aquarium from the St. Lawrence River, which was the location of the mould’s original discovery. Aquaria were checked twice daily for seven days and dead individuals were removed.