Utility of the Scope for Growth Index to Assess the Physiological Impact of Black Rock Harbor Suspended Sediment on the Blue Mussel, Mytilus edulis: A Laboratory Evaluation

摘要

The sensitivity, variability, and reproducibility of the scope for growth index (SFG) as an indicator of physiological condition was evaluated utilizing the blue mussel, Mytilus edulis, after exposure to highly contaminated dredged material. A preliminary experiment was completed to determine a no-observable-effects-concentration due to suspended reference sediment (REF) alone (50 mg/l). The effect of contaminated dredged material from Black Rock Harbor (BRH) was then tested using three treatments of suspended sediment: (a) 50 mg/l of BRH sediment (100 BRH), (b) 25 mg/l each of BRH and REF sediment (50-50 BRH/REF), and (c) 50 mg/l REF sediment alone (100 REF). This 26-day bioassay demonstrated a significant SFG reduction in mussels exposed to 100 BRH sediment (-3.63 J/hr) and the 50-50 BRH/REF treatment (-2.32 J/hr) compared to mussels exposed to 100 REF sediment (2.53 J/hr). This experiment was replicated to evaluate the reproducibility of the technique. The second experiment produced similar results with the 100 REF treatment mussels having a significantly higher SFG (10.22 J/hr) than both the 50-50 BRH/REF (0.51 J/hr) and 100 BRH (-1.07 J/hr) mussels. The data indicate that in a laboratory exposure the use of the SFG index with M. edulis provides a sensitive and reproducible technique for determining the chronic negative impact due to this dredged material.