Table 2. Numbers and wet weight of all attached dreissenids (>2 mm in size) and separately by species (Dreissena polymorpha and D. rostriformis bugensis) per infested host unionid (mean ± standard error, median, lower and upper quartiles, sample size) in studied lakes in 2011–2012.

Parameter	Lake St. Clair	Lake Erie	Lake Ontario
Number attached dreissenids:
mean ± standard error (sample size)	12.6±1.1 (133)	10.0±0.9 (499)	7.9±0.9 (372)
range	1–56	1–196	1–151
median (Q25–Q75)	8 (2–20)	3 (1–8)	2 (1–5)
Number D. polymorpha per host unionid:
mean ± standard error (sample size)	8.8±0.8 (133)	7.4±0.56 (499)	4.5±0.5 (298)
median (Q25–Q75)	6 (1–13)	3 (1–7)	1 (1–4)
Number D. r. bugensis per host unionid:
mean ± standard error (sample size)	3.8±0.5 (133)	2.6±0.5 (499)	3.4±0.7 (299)
median (Q25–Q75)	2 (1–6)	0	0
Wet weight of D. polymorphaper host unionid (g):
mean ± standard error (sample size)	7.65±0.69 (133)	2.21±0.33 (499)	3.68±0.40 (298)
median (Q25–Q75)	5.0 (1–10.2)	0.5 (0.2–1.4)	1.0 (0.4–3.0)
Wet weight of D. r. bugensisper host unionid (g):
mean ± standard error (sample size)	2.44±0.31 (133)	0.35±0.13 (499)	1.34±0.29 (296)
median (Q25–Q75)	0.9 (0–3.3)	0	0 (0–0.2)
Proportion D. polymorpha wetweight of total dreissenid weight(per host unionid):
mean ± standard error (sample size)	0.80±0.02 (133)	0.93±0.01 (499)	0.87±0.02 (298)
median (Q25–Q75)	0.9 (0.7–1.0)	1.0 (1.0–1.0)	1.0 (0.9–1.0)