Magothy health declines: Annual report finds underwater grasses vanishing

The Capital, Published February 20, 2008

If the Magothy River were a person, it would be on life support. The scientist who helps the Magothy River Association monitor the waterway gave it a 42 percent health rating for 2007, saying it looks worse than it has in years.

Acres of underwater grasses disappeared last year, and the river is the murkiest it has been since Tropical Storm Isabel flushed water-cleansing dark false mussels into it four years ago.

Dr. Peter Bergstrom, a biologist with the National Oceanic and Atmospheric Administration's Annapolis office, is scheduled to discuss his findings tonight during the sixth annual State of the Magothy address at Anne Arundel Community College in Arnold.

This is the first year NOAA has given the river an overall health score, though previous reports have included information about three indicators: water clarity, underwater grasses and dissolved oxygen.

A 100 percent rating would indicate a clear river flush with grasses that allow crabs, fish and other aquatic creatures to thrive.

"2007 was not great for the Magothy," Dr. Bergstrom said. "The number of underwater grasses is down at the lowest level they've been since 1995."

The Magothy had only 83 acres of submerged aquatic vegetation last year, according to a draft of Dr. Bergstrom's report released to The Capital. That was 165 fewer acres than in 2006.

The Chesapeake Bay Program's goal for the river is 579 acres, meaning the Magothy was at just 14 percent of its goal in 2007. The grasses are a crucial habitat for a number of fish species.

"That's a really sharp drop," Dr. Bergstrom said.

Water clarity, a key factor in the growth of underwater grasses, was equally poor last year.

The Chesapeake Bay Program's goal for clarity is at least 0.97 meters deep, which gives underwater grasses enough light to grow, Dr. Bergstrom said. In 2007, the water clarity was less than half of that, only 44 percent of the goal. That was the same finding from 2006.

The river fared best in dissolved oxygen, a crucial factor for aquatic life. The program's objective is at least 5 milligrams per liter through the water column; the river had 3.45 milligrams or 69 percent of that goal in 2007.

"Dissolved oxygen status rose in 2004 when mussels were abundant, dipped in 2005 when the summer was hot and calm, and then recovered to earlier levels," Dr. Bergstrom wrote in his report.

Warm water doesn't hold as much oxygen, he said.

The Magothy was at its recent peak in 2004, when storm surge from Isabel washed dark false mussels into the river. Like oysters, the mussels filter the water.

With the dark false mussel population thriving, the water was clear and the number of underwater grasses was up, Dr. Bergstrom said. The mussels also helped to filter out plankton, which decomposes and uses up oxygen after it dies.

But after a year, the mussels started to die off. No one really knows why.

"People keep asking me how to replicate what the mussels did," Dr. Bergstrom said.

Had the Magothy received a health assessment in 2004, it would have been about 65 percent, he said. In 2003 - the first year the State of the Magothy was compiled - the assessment would have been about 40 percent, Dr. Bergstrom said.

"(The assessment) is the sort of thing people want to know," he said. "So I went ahead and did it for the past years, and 2004 was the best year because of the dark false mussels. It's gotten worse since then."

MRA President Paul Spadaro remains optimistic.

"I think we're doing OK, considering all the problems we've had on the land," Mr. Spadaro said.

He was referring to Dobbins and Little islands, both of which have been at the center of development disputes for years.

"I'm disappointed there was such a change after the mussel episode, but we did learn a lot from that," Mr. Spadaro said. "It shows that we're on the right track with oyster restoration."

There are some things residents can do to help the Magothy, Dr. Bergstrom said. Oyster restoration efforts in the river have been under way since 2001, and the MRA has spearheaded underwater grass restoration projects six times in the past decade.

All of the projects had some survival for one to three years, with some plants spreading outside of the planting area, Dr. Bergstrom said. The MRA also has plans to grow wild celery in the upper end of the river this year.

He said he would also like to see more tree planting along the shore of the Magothy.

"Trees are good in a lot of ways. They stabilize shorelines, and they provide shade to cool the shore. It's good for birds and other animals, too," Dr. Bergstrom said. "Unfortunately, a lot of trees have been cut down so people can see the water better."

The MRA's Creek Watchers - volunteers who monitor the river and the shoreline for infractions such as dredging or building in a Critical Area Buffer Zone - also help.

"It's not just what's happening on the river - it's what's happening on the land all around the river," said Carl Treff, the MRA's volunteer coordinator. "So far, 115 people have reported incidents, and we have 25 sites being monitored. Things are looking up."

The State of the Magothy will be presented at 7 p.m. in the Cade Center for the Fine Arts at AACC. If inclement weather closes classes, the meeting will be rescheduled.

(Revised Feb 2008)