Asian Carps of the Genus Hypophthalmichthys (Pisces, Cyprinidae) ― A Biological Synopsis and Environmental Risk Assessment Cindy S. Kolar U.S. Geological Survey Upper Midwest Environmental Sciences Center 2630 Fanta Reed Road La Crosse, Wisconsin 54603-1223 Duane C. Chapman U.S. Geological Survey Columbia Environmental Research Center 4200 New Haven Road Columbia, Missouri 65201-8709 Walter R. Courtenay, Jr., Christine M. Housel, James D. Williams U.S. Geological Survey Center for Aquatic Resources Studies 7920 NW 71st Street Gainesville, Florida 32653-3071 and Dawn P. Jennings U.S. Fish and Wildlife Service North Florida Field Office 6620 Southpoint Drive South, Suite 310 Jacksonville, Florida 32216-0958 April 12, 2005 Report to U.S. Fish and Wildlife Service per Interagency Agreement 94400-3-0128 ii Contents Introduction..................................................................................................................................... 1 Genus and Species Description and Distinguishing Characteristics............................................... 2 Genus: Hypophthalmichthys (Bleeker 1860).................................................................. 2 Diagnostic Characteristics ..........................................................................................3 Species: Bighead Carp, Hypophthalmichthys nobilis (Richardson 1845) ....................... 3 Diagnostic Characteristics ..........................................................................................4 Species: Silver Carp, Hypophthalmichthys molitrix (Valenciennes 1844)...................... 5 Diagnostic Characteristics ..........................................................................................5 Species: Largescale Silver Carp, Hypophthalmichthys harmandi (Sauvage 1884)......... 8 Diagnostic Characteristics ..........................................................................................8 Hybrids of Hypophthalmichthys spp................................................................................ 9 Native Range................................................................................................................................. 10 Bighead Carp ................................................................................................................. 10 Silver Carp ..................................................................................................................... 12 Largescale Silver Carp................................................................................................... 13 Habitats, Migrations, and Local Movements................................................................. 14 Bighead Carp ................................................................................................................. 14 Silver Carp ..................................................................................................................... 17 Largescale Silver Carp................................................................................................... 19 Biology and Natural History......................................................................................................... 19 Temperature Tolerance .................................................................................................. 19 Bighead Carp ............................................................................................................19 Silver Carp ................................................................................................................20 Largescale Silver Carp..............................................................................................20 Salinity Tolerance .......................................................................................................... 21 Bighead Carp ............................................................................................................21 Silver Carp ................................................................................................................21 Largescale Silver Carp..............................................................................................22 Reproductive Biology .................................................................................................... 22 Fecundity...................................................................................................................22 Bighead Carp ..................................................................................................... 22 Silver Carp ......................................................................................................... 22 Largescale Silver Carp....................................................................................... 23 Sexual Maturity and Mating Behavior......................................................................23 Bighead Carp ..................................................................................................... 23 Silver Carp ......................................................................................................... 23 Largescale Silver Carp....................................................................................... 24 Spawning...................................................................................................................24 Bighead Carp ..................................................................................................... 24 Silver Carp ......................................................................................................... 25 Bighead and Silver Carps................................................................................... 26 Largescale Silver Carp....................................................................................... 27 Early Development ...................................................................................................27 Bighead Carp ..................................................................................................... 27 Silver Carp ......................................................................................................... 28 ii Largescale Silver Carp....................................................................................... 29 Feeding Habits ............................................................................................................... 29 Bighead Carp ............................................................................................................29 Silver Carp ................................................................................................................33 Largescale Silver Carp..............................................................................................37 Growth Rate and Longevity........................................................................................... 38 Bighead Carp ............................................................................................................38 Silver Carp ................................................................................................................40 Largescale Silver Carp..............................................................................................41 Response to Physical Stimuli......................................................................................... 42 Bighead Carp ............................................................................................................42 Silver Carp ................................................................................................................42 Largescale Silver Carp..............................................................................................44 Associated Diseases and Parasites................................................................................................ 44 Bighead Carp ................................................................................................................. 44 Silver Carp ..................................................................................................................... 48 Largescale Silver Carp................................................................................................... 55 Disease Transmittal to Native Fishes............................................................................. 56 Human Uses of Hypophthalmichthys............................................................................................ 57 Use as Human Food....................................................................................................... 57 Capture Fisheries for Hypophthalmichthys...............................................................57 Culture of Carps........................................................................................................58 Bighead Carp ............................................................................................................59 Silver Carp ................................................................................................................60 Largescale Silver Carp..............................................................................................61 Control of Algae ............................................................................................................ 61 Bighead Carp ............................................................................................................61 Silver Carp ................................................................................................................62