Lowered salinity levels in the upper Chesapeake Bay are being blamed for an intense but also concentrated die-off of oysters. State biologists say the die-off is limited to two areas north of the Bay Bridge and affected about two-percent of the state’s overall oyster harvest. The oyster bars hit hardest along the mouth of the Magothy River and Patapsco River, and also near Rock Hall. The “Baltimore Sun” says scientists also found that other oyster bars in the Bay, including some north of the Bay Bridge, were relatively unscathed. The die-offs are attributed mainly to an increase in the amount of fresh water flowing into the bay going back to the spring. State officials say it is a not an uncommon result when that happens.