Aerial and Field SAV Observations

by Staff | June 29, 2009
First comprehensive analysis shows 58% of seagrass meadows in decline

An international team of scientists warns that accelerating losses of seagrasses across the globe threaten the immediate health and long-term sustainability of coastal ecosystems. The team has compiled and analyzed the first comprehensive global assessment of seagrass observations and found that 58 percent of world’s seagrass meadows are currently declining.
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I kayaked on 6/14 to several areas that had SAV in past years on the Magothy River, in Cornfield Creek & nearby.

1. Hunters Harbor is a very shallow cove, only really accessible by paddle craft, and is not shown on the VIMS base maps.  It was mapped with SAV in 2005 as part of bed BB2.  It still had very dense SAV when I visited it in 8/06 (see 2nd paragraph under Lower Magothy of this report), when I found very dense Ec and Ms there, but it was not mapped with SAV that year.

I knew it had SAV on this visit when I saw 2 mute swans there.   There was much less SAV than I found in 2006, though; there was a carpet of Zp in some shallows and a bit of patchy Ms.  See map.

2. In 2008, a small bed was mapped near Long Point as I3 & K4 (see map).   I checked the eastern edge of the area of the 2008 bed and found sparse Zp, Ppc with clear bayonets, and Ppf.

3. Next I visited Cornfield Creek where there has been a dense bed mapped on the east side of the lower creek for many years.  That bed is still there (see 2008 VIMS map -bed H2, and the map from my visit) but the species composition may be changing, with less Ms & Ec and more Ppc & Ppu.   I found Ppc Ppf Ppu (photos in hand and water) and Zp there this year, with no Ms, Rm or Ec (all found there in the past).  Surveys I did with Bayland staff of the whole shore of Cornfield in 6/07 found Ms in this bed, and Ppu and Ec farther up the creek, but no Ppc (see report).  The changes since 2007 to this bed (added higher salinity Ppc, subtracted lower salinity Ec and Ms) suggest that elevetaed salinity in 2007-2008 may have been a factor in the changes.  I did not survey the rest of the creek on this visit.  I found Ppu in this same bed  in 8/06 (see report) but it was much less common then.  June is usually too early to find Rm in the Magothy; it usually comes up in July.

4. I finished in James Pond where SAV was last mapped in 2006 (see map).  I found 5 species on the west side of the pond (Zp Ppu Ms Ppf Ppc, with less Ms than in the past) and only 3 on the east side where density was less (Ppc Zp Ppu).  If these plants last over the summer, it may have mapped beds again this year.  I saw a small snapping turle swimming nearby (salinity was 5 ppt).  I was last in James Pond in 2005 when I found Ms, Ppf and Ec, with lots of Ms, so the species changes here in 2009 are similar to those in Cornfield (more Ppc and Ppu, less Ms and Ec compared to prior years).

Becky Raves Golden, MD DNR (Quads 32, 33)

We surveyed Kirwan and Marshy Creeks (Kent Narrows/ Prospect Bay) on 06/09/2009.  We didn’t see any grass in the second northside cove of Kirwan Creek, but there were a few sprigs of milfoil (Ms) and horned pondweed (Zp) floating nearby.  The first cove on the south side of Kirwan Creek and upstream areas contained sparse and short horned pondweed and redhead (Ppf) in thin patchy bands near shore. 

We also surveyed the northside (near Rt. 50) of Marshy Creek.   Patchy and sparse areas of horned pondweed, redhead and sago pondweed (Ppc) were seen fringing the shoreline, but the plants were longer here than in Kirwan Creek.

Water clarity in both creeks was relatively good, given the recent rains. 

by Cathy Wazniak | June 4, 2009

Underwater seagrass abundance in Maryland and Virginia’s coastal bays increased by 17 percent last year, from 9,319 acres in 2007 to 10,916 acres in 2008. While this increase may be a sign that the 3 year downward trend may have halted, it is still one of the lowest acreages seen in over a decade. This year’s 1,597 acre increase was driven by the expansion of grasses in Chincoteague Bay.
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by David Malmquist | June 4, 2009

Researchers at the Virginia Institute of Marine Science (VIMS) have created an interactive map that allows web users to see the coverage of underwater grasses in Chesapeake Bay and its tributaries.

The tool, created using Google Maps™ by researchers in the Submerged Aquatic Vegetation (SAV) program at VIMS, is designed to help resource managers, scientists, and citizens better track and visualize bay-grass restoration efforts. It is freely available on-line at web.vims.edu/bio/sav/maps.html.
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by David Malmquist | May 6, 2009

Professor Robert Orth of the Virginia Institute of Marine Science will present a public talk on his team’s success in ongoing efforts to restore underwater grasses to the seaside lagoons of Virginia’s Eastern Shore during the International Marine Conservation Congress in Washington, D.C. on May 20th.
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by Travis Loop & David Malmquist | April 29, 2009

The Virginia Institute of Marine Science’s annual bay grass monitoring program shows that the abundance of underwater grasses in Chesapeake Bay increased by 18 percent last year, from 64,917 acres in 2007 to 76,861 acres in 2008. This is the fourth largest total acreage of bay grasses recorded since the bay-wide survey began in 1984. Bay grasses are an excellent barometer of Bay health because of their sensitivity to small changes in water quality.
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I led a small group of paddlers to check SAV at Patuxent River Park/Jug Bay Naural Area in Prince George’s County on 5/30/09, as part of their “BioBlitz.”  We started at Jackson Landing and paddled south (downriver) as far as the mouth of Mataponi Creek (VIMS quads 159 & 41).  We wanted to look up in the creek but we ran out of time.

We found that the SAV was very sparse and short, just starting to come up.  Combined with the very murky water (Secchi 0.35 m) and higher than normal water levels, both due to recent rain, we could only see the plants in the very shallowest water.  Most were found by raking which is very slow.

We found 4 species:  Hv-hydrilla; Ec-Elodea; Nm-Najas minor (very short); and C-Chara or muskgrass.  See map for locations.  One hydrilla shoot still had a tuber attached (see photo).  Note the recurved, toothed leaves in this photo, usually 4-5 per whorl; the Ec we found had flatter, less toothed lieaves with 3 per whorl, with whorls more spaced out along the stem.

I led a group doing water & SAV monitoring on College Creek, on the Severn River in Annapolis, on 5/12/09.  When were were there on 4/30 we could not find any SAV beds at the upper end of the creek, but the tide was too high, there was heavy overcast, and we did not have much time to look.  On this visit with lower tides, some sun, and more time, we found that there were patches of dense horned pondweed (Zp) in the creek.  The attached map shows the 3 main areas where we found Zp, and 2 spots where we found redhead grass (Ppf, red symbols).

At the upper end of the creek, the extreme upper end was mostly clumps of filamentous algae with a few strands of Zp in it (green pushpin symbol).  A bit farther down, there were a few dense Zp beds near shore (other Zp is shown with a green teardrop shape).

The densest and most extensive Zp beds were in Peters Cove, just up the creek from the Rowe Blvd bridge.  This photo shows the beds all along the north shore of the cove, below Calvary Church.  There were patchier beds on the south shore where there was shading from trees, and we found a few live dark false mussels on a submerged log on this shore (see photo–the one in the center was alive).  These small clams were dense along this same shore last July before they were smothered by bryozoans in August 2008.  Salinity was a bit higher than normal for May this year (about 9 ppt).

The unnamed cove on the same side of the creek, between Rowe Blvd and King George St, had smaller Zp beds in the upper and and on its north shore (the south shore is heavily shaded by trees).  This photo shows the dense but small Zp beds in the upper end of this cove.  There were some black-crowned night herons in the trees here, as there were last year.

We found short sprigs of redhead grass (Ppf) in two spots, across the creek from each other.  One was on the point between the two coves, where none was planted to our knowledge, and the other was off the St John’s Living Shoreline, where Ppf was planted for several years (but not yet this year, so it counts for the VIMS survey–SAV species are not counted until they have survived at least a year).  Both small clumps were short, about 3-6″ tall.

Thanks to Claudia Donegan, Nick Maistrellis, and Doug Wise for helping with sampling.