ABSTRACT
Chapter 7 describes control options for dreissenids, mytillids, and corbiculids. This chapter describes physical, chemical, and biological methods to mitigate impacts of aquatic invasive gastropods. By physical methods we mean both physical removal, for example by hand, and physical properties of water, for example temperature; in some cases, this section includes even mechanical removal methods. Chemical methods include use of dissolved oxygen, pH, salinity, oxidizing chemicals, nonoxidizing chemicals, and molluscicides to reduce or eradicate snail infestations. Biological control includes use of predators or parasites. Cowie (2001), after reviewing the literature, concluded that use of snails as biological controls has rarely had adequate prerelease testing of snails. The postrelease monitoring of nontarget impacts has always been incidental. Cowie (2001) stated that the use of nonnative snails for biocontrol purposes is poorly regulated; many introductions are unof cial and sometimes illegal. Cowie (2001) recommended that use of snails as biocontrol agents, if implemented, must be based on adequate prerelease testing, postrelease monitoring, and genuine concern for preservation of native biodiversity. Biological control using predators can usually only reduce pest numbers to acceptable levels, not eradicate the pest (Cowie, 2002). Howarth (1991), Civeyrel and Simberloff (1996), Simberloff and Stiling (1996a,b), and Williamson (1996), to mention a few, have made it increasingly clear that biological control can be as environmentally dangerous as the use of chemical pesticides. Also, it is probably not going to be possible to eradicate invasive gastropods from areas where they have become widely established.
