Current research on the environmental impact of Eurytemora affinis in the Great Lakes is inadequate to support proper assessment. Potential:
Eurytemora affinis has the ability to feed on toxic cyanobacteria and dinoflagellates (Dinophysis spp.) (Engström et al. 2000, Setälä et al. 2009). While these do not appear to be their preferred food source, consumption of toxic phytoplankton results in the buildup of toxins in zooplankton tissue and feces, which consequently can accumulate in benthic organisms, fish, and organisms further up the food chain (Engström et al. 2000, Lehtiniemi et al. 2002, Setälä et al. 2009). Copepods are also common hosts for fish parasites (Piasecki et al. 2004). In particular, E. affinis is a probable host and vector for plerocercoids that can infect striped bass in the Sacramento-San Joaquin Estuary (Arnold and Yue 1997).
Mesocosm experiments indicate that E. affinis has the potential to control some populations of protozoan ciliates and rotifers when these prey items are found at high densities (Feike and Heerkloss 2009, Merrell and Stoecker 1998). Because E. affinis has become an abundant grazer in parts of the Great Lakes, it is possible that it has had important impacts on the food web—both adverse and beneficial (see below) (Lee et al. 2007).
Current research on the socio-economic impact of Eurytemora affinis in the Great Lakes is inadequate to support proper assessment.
Potential:
Outbreaks of cholera are sometimes correlated with copepods, which are common hosts of Vibrio cholerae (Colwell 2004, Lee et al. 2007, Piasecki et al. 2004). Cholera outbreaks tend to be associated with algal blooms and the rapid increase in copepods that follows (Piasecki et al. 2004). Eurytemora spp. are known to host V. cholerae and are the most common of known copepod hosts in the Chesapeake Bay, where this has been studied (Colwell 2004).
Eurytemora affinis has the ability to consume cyanobacteria and other toxic algal blooms; studies in the Baltic Sea indicate that this is likely an important mechanism of the biomagnification of toxins in organisms of economic importance, such as shrimp and fish (Engström et al. 2000, Karjalainen et al. 2008, Setälä et al. 2009).
There is little or no evidence to support that Eurytemora affinis has significant beneficial effects in the Great Lakes.
Potential:
Eurytemora affinis could be a significant prey item for fish and other planktivores. Thorp and Casper (2003) demonstrated such potential in an enclosure experiment with yellow perch (Perca flavescens) in the St. Lawrence River; 99% of E. affinis disappeared from fish enclosures, presumably due to predation.