Concurrent mobile on-site and in situ striped bass contaminant and water quality studies in the Choptank River and upper Chesapeake Bay
In situ and mobile on-site striped bass prolarval and yearling survival studies were conducted in the Choptank River and in the Chesapeake and Delaware (C & D) Canal area of the Upper Chesapeake Bay. Extensive chemical analyses of both organic and inorganic contaminants in the habitat water were performed and water quality parameters were monitored during these experiments. Surviving yearling striped bass were subjected to histological examination. Prolarval survival data from both the in situ and mobile on-site studies were similar for each spawning area. Prolarval survival ranged from 30 to 45% after 96 h of exposure to Choptank River water in four separate experiments (two in situ , two on-site); control survival was greater than 74%. Based on a comparison of laboratory toxicity data and reported field concentrations in the Choptank River for various water quality and contaminant conditions, the following combination of conditions was potentially stressful to striped bass prolarvae: low hardness (36 to 48 mg/L CaCO 3 ), monomeric aluminum (0.150 mg/L), cadmium (0.003 mg/L) and copper (0.040 mg/L). Yearling survival in both in situ and on-site tests ranged from 93 to 100% in both the control and Choptank River water after 9 d of exposure. Survival of striped bass prolarvae in C & D Canal water ranged from 52.5 to 70% after 96 h of exposure in four separate experiments. Control survival of prolarvae was not significantly different. Survival of yearling striped bass in on-site and in situ tests was 95% or greater in C & D Canal water and control water. Acute contaminant effects were not verified in the C & D Canal area.