Potential Interactions Between Planktivorous Asian Carp and Plankton Community in Western Lake Erie

Planktivorous Asian carp species, silver (Hypophthalmichthys molitrix) and bighead (H. nobilis) carp, have colonized the Mississippi River and its tributaries and now threaten to invade the Great Lakes.  Western Lake Erie is most vulnerable due to its shallowness and recent re-eutrophication coupled with summer blooms of Microcystis.  We examined Chinese and English Asian carp publications and changes in nutrients and plankton of western Lake Erie to predict potential Asian carp invasions and impacts.  Silver and bighead carp are warm-water spawners (min 18 ^oC) and eggs could hatch in < 3 days between 19-23 ^oC (summer in western Lake Erie).  Larvae of both species consume small zooplankton, but silver carp (> 15 mm) switch to feed mainly on phytoplankton.  Their zooplanktivorous nature may cause the zooplankton mid-summer decline phenomenon to occur earlier in western Lake Erie, which could affect diet and growth of YOY of other species.  Preference for Microcystis by Silver carp could help control its blooms.  However, studies have shown that fecal algae from silver and bighead carp are still viable, recycling both nutrients and algae back to the lake.