It's report card time for the Chesapeake Bay, and the annual assessment for another set of bay tributaries shows a bit of improvement over last year's dismal scores.

Last week, the Chesapeake Bay Program's bay barometer showed some modest gains for the Chesapeake that were no cause for great celebration.  Over the weekend, a similarly sobering report came out for the West and Rhode rivers south of Annapolis.

The levels of fish-sustaining dissolved oxygen in the rivers increased slightly, while the levels of water-fouling nutrients declined, according to the report card issued by the West/Rhode Riverkeeper.  Stream health, a measure of the diversity of fish and other aquatic life found, also gained a little ground.

But by other measures, the West and Rhode are still faltering, according to the riverkeeper's assessment.  Water clarity and underwater grasses were virtually rock bottom, and though last year there were no fish kills reported on the rivers, algae levels remained high.   And of 14 sites sampled in the rivers for disease-causing bacteria, 10 had elevated levels at least once last summer, while one spot registered unsafe readings half the time.  To see report cards for 2009 and 2008, go here.

Chris Trumbauer, the West/Rhode Riverkeeper, sounded a cautious note about the slight gains seen.  Many of the nutrients that foul the rivers are carried down the western Shore from the Susquehanna River, he said, and the mighty river's flow last year was down 25 percent from the year before.   That could explain the slight improvements in nutrients and dissolved oxygen, since they are linked.   There is no clear explanation for the increased signs of aquatic life found, Trumbauer wrote in an email.   But then again, only one river, the West, was sampled.

"Once again," the report concludes, "the collective data in this report show that the West and Rhode Rivers are not 'making the grade' for most of our measured indicators of water quality....Our rivers and the Bay have been in poor condition for decades.  We have made some progress over the years, only to give back those gains as population and development have increased."