More healthy news for waterways

Waterways that form the boundaries of Southern Maryland have been getting a cleaner bill of health lately, as evidenced by these three recent developments:

In March, in its annual report, the watchdog agency Potomac Conservancy gave the river its highest-ever grade, a B-.

Then last month, the Maryland Department of Natural Resources reported the findings of its latest winter dredge survey — the state’s blue crab population is up by 35 percent over the last year.

And then on Friday, DNR said it has mapped a new record high of 53,277 acres of submerged aquatic grasses in Maryland’s portion of the Chesapeake Bay.

It’s all good news for the entire bay watershed, but what does this all mean? Does it indicate that closer state regulatory scrutiny, conservation efforts of groups and individual citizens and cleanup work has been effective? Yes. Does it mean Southern Maryland and the state in general can let up now? No.

Let’s examine each piece of good news about the area’s waterways. Five years ago, the Potomac was judged to be quite sick, given a grade of D. In 2013, the group’s grade improved to a C. Hedrick Belin, president of the Potomac Conservancy, now says the group’s stated goal of making it a swimmable, fishable river again by 2025 can be attained. The group’s report highlighted that the top three pollutants in the river — nitrogen, phosphorus and sediment — have been on a steady decline. Some key indigenous species of fish are on the rise, such as white perch and shad. But Belin cautioned, “the Potomac is not in the clear yet.”

Let’s turn now to crabs. DNR’s winter dredge survey, conducted in concert with the Virginia Institute of Marine Science since 1990, is the primary assessment of the Chesapeake’s blue crab population. The 2016 report, using data collected from 1,500 sites throughout the bay, revealed that the crab’s numbers are up to 553 million.

DNR reported the numbers for both sexes were encouraging. The number of spawning-age females went from 101 million to 194 million since the last survey. That’s still below the state’s target of 215 million, but above the minimum threshold DNR established five years ago. And the number of adult male crabs more than doubled from 44 million to 91 million. This is the second-highest level since 1995, according to DNR. Experts attribute this to a warmer winter and slightly stricter rules on crab potters and trotliners.

Those are healthy signs, but vegetation is also a key component. The health of underwater grasses and water clarity are indicators of ample oxygen content, which in turn leads to the health of everything else in the watershed. DNR’s mapping of submerged aquatic grasses in Maryland’s part of the bay found that vegetation increased 29 percent from 2014 to 2015. DNR says Maryland is now at nearly 94 percent of its restoration goal of 57,000 acres of healthy aquatic grasses by next year.

All of this is encouraging news. But the key to maintaining healthy waterways remains responsible stewardship, which includes conservation and avoiding pollution and litter. That’s something to which everyone can contribute.