Environmental Engineering Reference
In-Depth Information
Ctenopharyngodon idella
Native HUCs
HUC 8 level record
HUC 6 level record
Nonspecific state record
Map created on 5/24/2012. United States Geological Survey
Ctenopharyngodon idella
averages 18-25 inches
FIGURE 17.13 U.S. distribution of grass carp from the USGS Nonindigenous Aquatic Species center and a
photograph of the triploid grass carp. (Courtesy of New York Department of Environmental Conservation.)
(Center et al. 1998). Their larvae burrow into the hollow stem of the alligator weed and feed on the
leaves, while the adults feed primarily on the leaves. They have been so successful that alligator
weed is currently only a nuisance in local areas (Cooke et al. 2005).
17.5.7.3 Water Hyacinth Weevils ( Neochetina eichhorniae and N. bruchii )
Water hyacinth weevils (Figure 17.14) are native to Central and South America, and were introduced
to control water hyacinths. A water hyacinth is a free-loating invasive aquatic plant, native to South
America and was irst introduced as an ornamental plant into the United States in 1884 at the Cotton
States Exposition in New Orleans. The two species of weevils (Figure 17.15) were introduced into
the United States in the 1970s to help control water hyacinths (Chilton 2004). These weevils do
not kill water hyacinths quickly, but cause stunted plant growth with less lowering and a reduced
competitive ability against native plants. Past studies have demonstrated that it may take from 3 to
6 years before signiicant impact, ultimately leading to decreases in the water hyacinth populations
(Grodowitz et al. 2000).
 
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