Waging War Against the Zebra Mussel 403 Calculated viability values for sites 1-10 in Lake A using model 1 g 176826813.04 28002231246 3|7.7417611.26 16.511.14 58.0216.91140 67.5913.410.27 7|7.6616.911.04 87.8216.61114 79515.711.09 10 8612.010.26 The model predicts that sites 6 and 10 should not be suitable habitats, while the other eight sites should be. Figure 1, which plots date vs. juveniles/day for each of the sites, shows that the data agree well with our model. Sites 6 and 10 have virtually no zebra mussel population growth, and sites 1, 2, 3,4,5 and 9 all show evidence of infestation. Although it is predicted that sites 7 and 8 should be susceptible to invasion, enlargement of Figure 1 shows that these two sites are not supporting large populations; correspondingly, V for sites 7 and 8 is relatively low. Also, the source of the zebra mussel invasion was site 1 hence the more southerly sites have had longer to form stable populations than the northern sites 7 and 8. With threshold ph of 7. 4 and threshold calcium level of 12 mg/L, the model-which predicts that sites 6 and 10, whose values border on the threshold, are not likely to be habitable-is consistent with the literature Graph 1. Relative Population of Locat NE三 60000 3 40000 7120/95 12/1/96 4/15/98 8/28/99 Figure 1. Relative populations at sites 1-10Graph 1. Relative Population of Locat 0 20000 40000 60000 80000 100000 120000 140000 7/20/95 12/1/96 4/15/98 8/28/99 1/9/01 Date Juveniles/day/m^2 Location 1 Location 2 Location 3 Location 5 Location 9 Waging War Against the Zebra Mussel 403 Table 1. Calculated viability values for sites 1–10 in Lake A using model 1. Site pH [Ca] V mg/L 1 7.68 26.8 13.04 2 8.00 22.3 12.46 3 7.74 17.6 11.26 4 7.84 16.5 11.14 5 8.02 16.9 11.40 6 7.59 13.4 10.27 7 7.66 16.9 11.04 8 7.82 16.6 11.14 9 7.95 15.7 11.09 10 7.86 12.0 10.26 The model predicts that sites 6 and 10 should not be suitable habitats, while the other eight sites should be. Figure 1, which plots date vs. juveniles/day for each of the sites, shows that the data agree well with our model. Sites 6 and 10 have virtually no zebra mussel population growth, and sites 1, 2, 3, 4, 5, and 9 all show evidence of infestation. Although it is predicted that sites 7 and 8 should be susceptible to invasion, enlargement of Figure 1 shows that these two sites are not supporting large populations; correspondingly, V for sites 7 and 8 is relatively low. Also, the source of the zebra mussel invasion was site 1, hence the more southerly sites have had longer to form stable populations than the northern sites 7 and 8. With threshold pH of 7.4 and threshold calcium level of 12 mg/L, the model—which predicts that sites 6 and 10, whose values border on the threshold, are not likely to be habitable—is consistent with the literature. Figure 1. Relative populations at sites 1–10