Assessment of lake suitability to zebra mussel invasion based on calcium concentrations

We reviewed the scientific literature addressing physiological constraints of zebra mussel and found seven studies that measured the effects of water calcium concentrations (mg/l, hereafter Ca) on zebra mussel development and growth (Jones and Ricciardi 2005, Allen and Ramcharan 2001, Hincks and Mackie 1997, Mellina and Rasmussen 1994, Ramcharan et al 1992, Strayer 1991, Sprung 1987). A 95% confidence interval (CI) was applied to the distribution of the calcium concentration thresholds identified in these studies to establish a lower limit for zebra mussel survival. The value obtained for this lower threshold was 10 mg/l (mean mg/l Ca – 95% CI). Similarly, we calculated an upper threshold of 21 mg/l (mean mg/l Ca + 95% CI). These thresholds delimited three classes of lakes: not suitable to zebra mussel invasion (mg/l Ca < 10), borderline suitable (10< mg/l Ca < 21) and suitable (mg/l Ca > 21).