The mean levels of Vtg-like protein in the gonad of mussels caged in the NSR varied between sites (Fig. 7), with significantly lower levels of Vtg-like protein in mussels caged at NSR3, NSR4 and NSR6. Gillis et al. (2014a) observed slightly elevated levels of Vtg-like proteins in mussels (L. costata) caged in a plume of municipal wastewater, but only when data for females were excluded. In contrast, Hellou et al. (2003) observed reduced levels of Vtg-like proteins in the PP242 of female marine mussels (M. edulis) collected from intertidal regions impacted by municipal wastewater, a response similar to the one seen here in the gravid mussels caged at NSR3 and NSR4.
Fig. 7. Vitellogenin abundance per mg in the gonads of mussels caged at 5 sites (only one reference site is used for this component) within the NSR (nNSR1 = 10; nNSR3 = 10; nNSR4 = 8; nNSR5 = 10; nNSR6 = 10). Bars (mean ± SE) identified with an asterisk (*) are significantly (p < 0.05) different from control. Open bar represents control site.Figure optionsDownload full-size imageDownload as PowerPoint slide