Double-Crested Cormorant Modeled Foraging Range

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Notes:

For the Double-Crested Cormorant under existing conditions and project conditions, when we evaluated each constituent individually, we found that the concentration of each constituent did not exceed a threshold for effects, but when we evaluated the combined concentrations of PCB's, DDT and Mercury, it did slightly exceed the. threshold above which reproduction effects might be expected. For the Cormorant, we assumed that the foraging range would be centered around the dredging area. On the left here, it shows the foraging range that we assumed for the platform area, and over here to the East Bay Shoals. And this analysis assumes that there may be some individual Cormorants just feeding within this area for a period of at least several months, and it also assumes that the fish that they are feeding on are not leaving the area during that period. Now, in fact, most fish species do tend to move around the Bay quite a bit, and especially during dredging they are actually more likely to avoid this area, but we did want to evaluate the worse case scenario. Under this scenario, the maximum increase in dose of each constituent that we predicted to the Cormorant is expected to increase by about 26 percent as compared to existing conditions. Now most Cormorants, as I said, would be feeding in other areas of the Bay as well, and the average increase in dose for Cormorants around the Bay would be more like about two percent.