What types of organisms prey on Dreissena? Combining North American and Eurasian records, birds (36 species) and fish (15 species eating veligers and 38 species eating attached mussels) have been the most commonly reported predators (Molloy et al. 1997). The number of fish and bird species that have been documented as predators can be misleading, however, since most literature references contain records of only occasionally finding a few Dreissena in the stomachs of the predators listed. Records of field documented predation also include copepod and coelenterate consumption of pelagic larvae and observations of leeches, crabs, crayfish, and mammals eating attached mussels (Molloy et al. 1997).
Birds have been the most intensively studied natural enemies of Dreissena (Molloy et al. 1997). Consumption of attached Dreissena has been recorded for at least 21 species in Eurasia and 20 in North America. Only five species — Greater Scaup (Aythyamarila), Goldeneye (Bucephalaclangula), Oldsquaw (Clangulahyemalis), Herring Gull (Larusargentatus), and White Winged Scoter (Melanittafusca) — have been observed eating Dreissena both in Eurasia and North America. Five diving ducks — Tufted Duck (Aythyafuligula), Pochard (Aythyaferina), Greater Scaup (Aythyamarila), Lesser Scaup (Aythyaaffinis), and Goldeneye (B. clangula) — and one diving rail, the Coot (Fulicaatra), are the most well-documented avian predators of Dreissena (Molloy et al. 1997).
Molloy et al. (1997) indicated that 10 Eurasian and 5 North American fish species within five families have been field documented as containing planktonic Dreissena larvae in their alimentary tracts: Cyprinidae (7 species), Clupeidae (3 species), Osmeridae (2 species), Percidae (2 species), and Percichthyidae (1 species). Consumption of Dreissena attached to substrates has been recorded for at least
13 fish families, including 14 species within 10 families in North America and 27 species within 9 families in Europe.
Fish known or suspected to be predators of zebra mussels in North America.
Fish known to be predators of zebra mussels in Europe.
Only three species -- the common carp (Cyprinuscarpio), pumpkinseed (Lepomisgibbosus), and round goby (Neogobiusmelanostomus) -- have been field documented as predators on both continents. Another 13 North American fish species have been mentioned in the literature as potential predators, based primarily on their documented feeding on other bivalve species in the field (Molloy et al. 1997).
Although predators, particularly fish and birds, have been documented on occasion to consume Dreissena at high rates (Molloy et al. 1997), this does not necessarily mean that they have a significant long-term impact in controlling Dreissena densities.