by Peter Bergstrom
February 16, 2010
As Aldo Leopold and many other environmental writers have stressed, attachment to "special places" promotes environmental stewardship. For me, two of those special places were underwater. They were submerged aquatic vegetation (SAV) beds in two rivers near where I live and work, the Magothy and the Severn. Those beds were special to me because they were two of the first places that I saw SAV beds, starting in 1992. I use the past tense because as of last summer (2009), those two SAV beds are gone, part of a recent decline of SAV in both rivers.
The special SAV bed on the Magothy was in the lower part of the river on the western shore of Gibson Island. I first visited it in the summer of 1992, before it was mapped in the Virginia Institute of Marine Science (VIMS) SAV survey. I was doing volunteer water monitoring with a lifelong Magothy resident, Dan Zivi. Because he grew up here, Dan remembered when the grasses were abundant in the 1960s, and he knew there was a small remnant SAV bed. We stopped there in his boat to see it. It didn’t look like much; just a few spindly stalks of redhead grass in shallow, murky water. But it held great promise.
The following year, 1993, that bed was large and dense enough to be mapped in the VIMS SAV survey, along with a few nearby beds.
The recovery of SAV in the Magothy had started. That Magothy SAV area would peak in 2005 at 125 hectares (309 acres), which was 53 percent of the restoration goal.
By 2009, the Magothy SAV area was down to only 5 hectares (12 acres), just 2 percent of the goal. The SAV bed I first saw on Gibson Island’s shore was gone.
The first SAV bed I saw on the Severn was also special because it was large and dense right from the start, and it was the first field trip I made with Bob Orth of VIMS, who has boundless energy when SAV is involved. This bed must have been growing for years on a wide shoal outside of Asquith Creek. In the summer of 1994, the plants were tall enough to be visible from the air, and thus they were mapped in the SAV survey.
Bob Orth, a VIMS scientist who supervises the annual aerial SAV survey, wanted to see the “new” bed in the summer of 1994, so several of us went there with him in a small boat. I wasn’t familiar with the Severn’s bottom features, but Bob knew the bed was on a large shoal. As soon as we saw the edge of the bed, he jumped in the water. I was not prepared to jump in the water, so I stayed in the boat, but I leaned over to take a photo of a blue crab doubler that was caught in that bed as we explored it.
I had just started working at the U.S. Fish & Wildlife Service’s Chesapeake Bay Field Office, mainly to study and protect SAV, so I was happy.
Hence my sadness in summer 2009 when I visited this bed to do SAV sampling and found that, just like the bed near Gibson Island, it was almost gone. This was confirmed by the VIMS SAV map that was just completed. There was still a bed north of Asquith Creek in 2009 (labeled J4), but it no longer extends onto the shoal at the mouth of the creek.
What does the loss of these two SAV beds in 2009 mean for the future of SAV in the Bay? For me their loss is partly symbolic, and I know that almost all SAV beds come and go, sometimes returning after they disappear. I’m not that worried about the Severn SAV bed because there were still some large and dense beds nearby, although SAV in the Severn may have declined overall in 2009.
I am worried about the future of SAV in the Magothy, however, because of the large SAV area declines since 2005. It’s also troubling that the river's water clarity got worse again last year; data collected by Magothy River Association volunteers (including myself) showed water clarity was down to the lowest status we’ve measured (14 percent of the goal). Details of these changes will be in the forthcoming Magothy River Index, which I will present at the annual State of the Magothy meeting at Anne Arundel Community College on Wednesday, February 17 at 7:00 p.m.
What can we do about these declines in aquatic health in the Magothy and in other rivers? See this brochure from the Department of Natural Resources for some ideas on what you can do in your yard to improve aquatic health in the rivers near where you live. I’ve done many of these in my yard.
However, I think it will take more than changes in our yards to reverse the declines in aquatic health in the Magothy and in other rivers. The marked improvements in aquatic health that we saw in the Magothy and some nearby rivers in 2004 were caused by millions of tiny dark false mussels filtering the water. We estimated there were 400 million of them in one creek, Cattail Creek, that year. I live in the Cattail Creek watershed and I’ve done water monitoring there for 19 years, and 2004 had the best water clarity and dissolved oxygen status I ever recorded there. To get the same improvements in aquatic health by reducing stormwater runoff, we’ll need more than a few rain gardens. I think a good start would be stormwater retrofits in all of the waterfront communities, including mine, that lack any stormwater management facilities, because the communities were built before these were required. Who would pay for these expensive retrofits, and where would we put them? I’m not sure. One option could be to set up a special taxing district in communities to pay for stormwater retrofits. Crofton and other communities have done this for decades to pay for extra police protection. Taking actions like this directed at improving our environment would really demonstrate commitment to cleaning up the Bay.
submerged aquatic vegetation (SAV) bay grasses (SAV)