400 The UMAP Journal 22. 4(2001) the calcium concentration in the lake will significantly enhance its suitability as zebra mussel habitat We find that using the goby fish to reduce zebra mussels is not a feasible op tion if the community is concerned with ecological impact, due to the invasive nature of the goby. Environmental Factors in the Spread of Zebra mussels We first discuss the characteristics of a suitable breeding habitat and then address how the population is unintentionally introduced to new areas opulation growth depends on successful reproduction and survival to adulthood. Veligers, zebra mussel larvae, are more sensitive to stress in their surrounding environment and therefore have more stringent survival require ments. Hence, we examine environmental conditions that can cause stress for the zebra mussel, especially in the larval and juvenile stages Ion Concentrations and ph Calcium is required for the viability of zebra mussel populations because it is a major component in their shells. Alkalinity, which is directly linked to calcium concentrations, is an important variable in determining habitat suit- ability for zebra mussels. Calcium concentrations of 12 mg/L and alkalinity corresponding to 50 mg CaCO3/L are required for adult zebra mussel popula tions [Heath 1993]. A calcium concentration of 12 mg/L is also the minimum required for embryo survival, though higher concentrations enhance egg fer tilization and embryo survivorship [ Sprung 1987] Phosphorous and nitrogen are significant factors to zebra mussel population growth because they are critical nutrients for the freshwater phytoplankton that comprise the primary food source of the zebra mussel. Thus, they are an indirect measure of food availability Baker et al. 1993 The pH of the water is another critical factor. Adults require a pH of about 7. 2; in lower pH environments, they experience a net loss of calcium, sodium, and potassium ions, and in very acidic waters adult zebra mussels eventu- ally die because of ion imbalance [Heath, 1993]. Adults can survive in pH 7 environments, but eggs survive only between pH 7.4 to 9.4 [Baker et al. 1993 Temperature Adult mussels can survive temperatures from 0C to 32C, but growth oc curs only above 10C [Morton 1969] and breeding is triggered only in temper atures of at least 12C [Heath 1993]. Higher temperatures increase overall egg400 The UMAP Journal 22.4 (2001) the calcium concentration in the lake will significantly enhance its suitability as zebra mussel habitat. We find that using the goby fish to reduce zebra mussels is not a feasible op￾tion if the community is concerned with ecological impact, due to the invasive nature of the goby. Environmental Factors in the Spread of Zebra Mussels We first discuss the characteristics of a suitable breeding habitat and then address how the population is unintentionally introduced to new areas. Population growth depends on successful reproduction and survival to adulthood. Veligers, zebra mussel larvae, are more sensitive to stress in their surrounding environment and therefore have more stringent survival require￾ments. Hence, we examine environmental conditions that can cause stress for the zebra mussel, especially in the larval and juvenile stages. Ion Concentrations and pH Calcium is required for the viability of zebra mussel populations because it is a major component in their shells. Alkalinity, which is directly linked to calcium concentrations, is an important variable in determining habitat suit￾ability for zebra mussels. Calcium concentrations of 12 mg/L and alkalinity corresponding to 50 mg CaCO3/L are required for adult zebra mussel popula￾tions [Heath 1993]. A calcium concentration of 12 mg/L is also the minimum required for embryo survival, though higher concentrations enhance egg fer￾tilization and embryo survivorship [Sprung 1987]. Phosphorous and nitrogen are significant factors to zebra mussel population growth because they are critical nutrients for the freshwater phytoplankton that comprise the primary food source of the zebra mussel. Thus, they are an indirect measure of food availability [Baker et al. 1993]. The pH of the water is another critical factor. Adults require a pH of about 7.2; in lower pH environments, they experience a net loss of calcium, sodium, and potassium ions, and in very acidic waters adult zebra mussels eventu￾ally die because of ion imbalance [Heath, 1993]. Adults can survive in pH 7 environments, but eggs survive only between pH 7.4 to 9.4 [Baker et al. 1993]. Temperature Adult mussels can survive temperatures from 0◦C to 32◦C, but growth oc￾curs only above 10◦C [Morton 1969] and breeding is triggered only in temper￾atures of at least 12◦C [Heath 1993]. Higher temperatures increase overall egg