While conditions in the Chesapeake Bay have improved in several critical areas over the past year, the overall score in the Chesapeake Bay Foundation’s 2010 State of the Bay report is still only 31 out of a possible 100.

The report, released this week, is based on information garnered through monitoring and in-the-field observations about various fisheries, habitat components, and pollutants. CBF uses these indicators to keep score on the health of the Chesapeake Bay.

The resultant score, calculated regularly since 1991, is measured against a total of 100, which represents the conditions found in the bay when Captain John Smith first explored the area in the early 1600s. While 100 is the theoretical ideal, a score of 70 is good enough for a grade of A+.

The most significant gain since 2008, the last time the State of the Bay report was published, was in the number of crabs in the bay. The adult crab population more than doubled, from a low of 120 million crabs in 2008 to ...