Relationship between bioenergetics responses and organic pollutants in the giant mussel, Choromytilus chorus (Mollusca: Mytilidae).

Samples of Choromytilus chorus (giant mussel) were collected at three sampling stations exposed to different degrees of pollution along the south-central portion of the Chilean coast in spring 1998 and summer 1999. Measurements were carried out on clearance rate, absorption efficiency, and oxygen consumption of the mussels under controlled laboratory conditions, and related to analytical data on organic pollutants in their tissues. Scope for growth (SFG) was employed as a physiological index to evaluate stress produced by pollutants existing at each sampling site. Individuals from San Vicente bay (highly polluted) showed negative SFG values in spring (-4.6 J/h per g) and summer (-3.5 J/h per g). These results indicated severe stress related to the accumulation of toxic compounds in their tissues. Specimens from Corral bay (medium level of pollution) gave a SFG of 15.5 J/h per g in spring and 6.5 J/h per g in summer, while those from Yaldad bay (low pollution) presented an inverse situation was observed with SFG values of 6.2 J/h per g in spring which was lower than the summer value of 25.7 J/h per g. There was a significant negative correlation between the SFG of the different populations of C. chorus and the concentrations of organochlorines (OChs) and polynuclear aromatic hydrocarbons (PAHs) in their tissues.