Aerial and Field SAV Observations

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Hart-Miller Island SAV September 2013 Survey

September 18th, 2013 · Posted by rgriner· No Comments

 

Maryland Environmental Service (MES) Environmental Staff conducted an SAV survey along the western side of Hart-Miller Island (HMI) on September 13, 2013.  HMI is located at the mouth of Back River near Hawk Cove in Baltimore County.  Observations were made along two 3 mile transects 20 ft. and 50 ft. off of the western shoreline where water depths are shallow enough to support SAV growth, specifically from the most southern tip of the Hart Island remnant to the southern end of the Miller Island remnant.  The SAV beds were mainly observed by using a modified thatch rake, attached to approximately 15 yards of nylon rope, off of a boat.  Transects are split from southern tip of Hart Island to MES pier, MES pier to Drum Point, Drum Point to just south of the HMI DNR Start Park beach jetty, beach Jetty 1 through 14, and just north of the beach jetties to the southern end of Miller island. 

 

The observed bay grasses in the September 2013 survey declined significantly compared to previous years.  Only one species, wild celery (Vallisneria americana) was identified and was found in sparse beds between the beach jetties and toward the end of Millers Island. The wild celery abundance increased slightly from the June 2013 survey.

 

The average Secchi depth during the September survey was 1.29 ft.  The majority of SAV was observed between the jetties.  Water depth ranged from 1.2 ft. to 5.6 ft.  Overall estimated coverage of SAV in the area surveyed was 10%.

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Hart-Miller Island SAV June 2013 Survey

August 13th, 2013 · Posted by rgriner· No Comments

Maryland Environmental Service (MES) Environmental Staff conducted an SAV survey along the western side of Hart-Miller Island (HMI) on June 27, 2013.  HMI is located at the mouth of Back River near Hawk Cove in Baltimore County.  Observations were made along two 3 mile transects 20 ft. and 50 ft. off of the western shoreline where water depths are shallow enough to support SAV growth, specifically from the most southern tip of the Hart Island remnant to the southern end of the Miller Island remnant.  The SAV beds were mainly observed by using a modified thatch rake, attached to approximately 15 yards of nylon rope, off of a boat.  Transects are split from southern tip of Hart Island to MES pier, MES pier to Drum Point, Drum Point to just south of the HMI DNR Start Park beach jetty, beach Jetty 1 through 14, and just north of the beach jetties to the southern end of Miller island. 

 

 The observed bay grasses in the June 2013 survey declined significantly compared to previous years.  Only two species wild celery (Vallisneria americana) and curly pondweed (Potamogeton crispus) were identified. Wild celery was more abundant and on average was found in sparse beds between the beach jetties and toward the end of Millers Island.  Curly pondweed was noted in very sparse beds between the beach jetties. 

 

The average Secchi depth during the June survey was 1.6 ft.  The majority of SAV was observed between the jetties.  Water depth ranged from 3.0 ft. to 7+ ft.  Overall estimated coverage of SAV in the area surveyed was 5 %.

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Honga River, July 2013

July 18th, 2013 · Posted by admin· No Comments

Lee Karrh, MD-DNR (Quad 073)

We did our transect work on the Honga River on 7/17/2013.  Generally, the beds near Cedar Point (N38.29065 W76.14267) looked awesome.  There was very dense Rm, extending roughly 225 meters from shore with an amazing amount of flowers and seeds.  Water clarity was ok, not stellar but not poor.  I estimate Secchi depth away from the grass beds to be ~1 meter.

At another location (N38.29652 W76.10600), we found very sparse Rm , but infinitely more than the zero we’ve seen in the previous 3 years.

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6/27/13 Aerial Update

June 27th, 2013 · Posted by Robert Orth· No Comments

Bob Orth, VIMS
I hope you are all having a good year with your work around the bay. The weather has been really challenging for us given how windy it has been almost all spring. I don’t think we have had two successive days with low winds. It has played havoc with our field schedule, as well as the annual monitoring. As usual, we watch the weather sites 24/7 and were able to fly on those few available good weather days to obtain quite a bit of photography. We were able to fly all the lower bay western shore up to the mouth of the Potomac River and the bayside up to and including Smith and Tangier Islands, Crisfield, and the Honga River. We were expecting to complete the rest of the mid-bay area this week but it has been windy again, which kept the planes on the ground.

As you all know by now, SAV numbers were down for most of the bay in 2012 with the baywide number one of the lowest we had noted since we started the annual survey in 1984. While we will not have accurate mapped areas for the places we have just flown until later this summer, here are some general observations for those areas.

Lower Bay western shore – SAV beds in the James, York, and Back rivers and Poquoson Flats appear to have expanded and gotten denser compared to 2012. In the Mobjack Bay, one of the areas that always have lots of SAV, there are some interesting and enigmatic changes. In some places beds have gotten patchier in 2013 but in other areas beds have gotten denser. The transects that we conduct each year document an increasing percentage of widgeongrass in Mobjack Bay, which may be driving the patterns visible on the aerial imagery. Moving up bay to the Piankatank and Rappahannock rivers, as noted in previous years, there continues to be very little SAV and what we are seeing is mostly widgeongrass. However, there are a few areas that do appear denser and have expanded some. Finally, the area from the mouth of the Rappahannock to the Potomac River is really sparse, similar to last year, with widgeongrass dominant in this region.

Lower and mid-bay areas of the eastern shore – most of the beds along those bayside creeks are generally located near the mouths or just outside the mouth along the mainstem but sandwiched between large offshore sand bars and the mainland. The general pattern seems to be similar to what we are observing along the western shore – many beds have both expanded as well as gotten denser. In Island Bay, off of Big Marsh in Pocomoke Sound, SAV has expanded into areas we have never mapped before, a substantial increase that appears to be driven by widgeongrass based on some ground observations. SAV beds in the Tangier and Smith Island areas look good – dense and expanded. Lastly, the Honga River and Barren Island areas appear to have similar patterns – thicker beds with some expansion, with widgeongrass dominating up here.

So all in all, it appears 2013 is starting out as a better year for SAV than was 2012, so far. But remember that the 2012 beds were still a far cry from what we observed in earlier years. It is great to see what is happening this year – let’s hope the summer remains cool.

Finally, please don’t forget to send us any SAV ground observations you are making so we can include them in our final report.

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Nassawadox Creek, June 2013

June 18th, 2013 · Posted by admin· No Comments

Barry Truitt (Quad 124)

During his June visit to Nassawadox Creek, Barry Truitt of The Nature Conservancy noticed Ruppia “everywhere”.

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Widgeon grass in Island Bay

June 10th, 2013 · Posted by admin· No Comments

Ken Schultz (Quad 108)
I spent some time exploring Island Bay. It was turbid, and I could not see the grass, even in 2 feet of water, but I could definitley read large areas of it on my sonar throughout the area. My GPS/sonar has a good map of that bay so I was able to get close to -75.774480, 37.797755 and -75.772933, 37.794640 Decimal Degrees. Both were 4 to 4.5 feet deep (that was midway through the incoming tide, though there was little water movement as the wind was pushing the water out of the bay) and loaded with grass. I dropped the anchor and came up only with widgeon grass in both places. Not sure if there’s any eelgrass, but all I saw was widgeon; it had many seed pods in it.

Widgeon grass, Island Bay

Widgeon grass, Island Bay

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SAV in the Potomac River at Belmont Bay, April 2013

April 21st, 2013 · Posted by nrybicki· No Comments

Nancy Rybicki, USGS (Quad 039)
I was just in the Potomac River at Belmont Bay, near Kanes Creek, observing SAV at a very low tide (4/21/13). I walked from near the Mason Neck visitor center to Kane’s creek. I was walking in the shallow water and identified 7 species of SAV that were growing at a density of ~ 10% cover maybe 60 m from shore. I identified a Potamogeton, maybe P. pusillus, Zannichellia, Vallisneria, Hydrilla, Myriophyllum, Ceratophyllum, and a floating Heteranthera. The warm spell April 9th must have triggered the Val and hydrilla tubers to germinate, and all species of the plants were all tiny (~5cm long) , it was a very sandy bottom and the tubers were still attached via shallow rhizomes extending 3 to 7 cm into the sand. The floating Heteranthera dubia was just greening up and still attached to last years dead, black stems. There were a dozen Canadian Geese resting nearby and I found a goose egg on the beach. The huge exotic snails and freshwater mussels are plentiful here.

I also walked from the Mason Neck visitor center to Sandy Pt. I passed the Chesapeake Bay Foundation’s Vallisneria restoration site in Belmont Bay, not far from Sandy Pt. The recent winds had destroyed the exclosure they had placed around the recently planted seedlings, and no seedlings were visible.
There must be a Myriophyllum bed nearby. I don’t know where the Myriophyllum bed was, I didn’t observe it. Many ~1 ft length fragments of healthy, bright green, Myriophyllum were wrapped up in the Chesapeake Bay Foundation’s exclosure (plastic mesh, mesh now detached from the ring of pvc poles). Myriophyllum fragments were all along the shoreline in Belmont Bay.

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2012 was a good year for the lower Chester

February 19th, 2013 · Posted by Terry Willis· No Comments

Terry Willis (Quad 026)

We had a good SAV year in the lower Chester last year (2012), with growth in some places where it had only been sparse in recent years.  The waterfowl are liking it.  Biggest thing was resurgence of elodea.  Note that despite local dry conditions salinity remained on the moderate side even into August (I have seen 16+ppt in really dry years).  I would guess much water from elsewhere must have been coming over Conowingo.  Secchi depths in the summer still mostly .5-.6m except in the midst of the beds, where it is common to see 1m or more.  It is amazing how much growth can occur under the proper conditions in a very short time, must be many fold more than what planting efforts can accomplish in the same interval.

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Hart-Miller Island (HMI) - 2012 SAV Survey Results

November 30th, 2012 · Posted by rgriner· No Comments

Maryland Environmental Service (MES) Environmental Staff conducted SAV surveys along the western side of Hart-Miller Island (HMI) on June 21 and September 25, 2012.  HMI is located at the mouth of Back River near Hawk Cove in Baltimore County.  Observations were made along two 3 mile transects 20 ft. and 50 ft. off of the western shoreline where water depths are shallow enough to support SAV growth, specifically from the most southern tip of the Hart Island remnant to the southern end of the Miller Island remnant.  The SAV beds were observed by using a modified thatch rake, attached to approximately 15 yards of nylon rope, off of a boat.  Transects are split from southern tip of Hart Island to MES pier, MES pier to Drum Point, Drum Point to just south of the HMI DNR Start Park beach jetty, beach Jetty 1 through 15, and just north of the beach jetties to the southern end of Miller Island.   

June 2012 survey results were similar to previous years.  Five SAV species were identified and are listed in order of abundance: wild celery, redhead grass, curly pondweed, Eurasian watermilfoil, and horned pondweed. Wild celery on average was found in sparse to moderate beds.  Redhead grass and curly pondweed were noted in very sparse beds between Drum Point and the beach jetties. Eurasian watermilfoil and horned pondweed were noted in very sparse beds between the jetties.   Coontail was also noted in this area. 

The average Secchi depth during the June survey was 1.7 ft. The majority of SAV was observed between the beach jetties.  Water depth ranged from 2.4 ft. to 5.8 ft.  Overall estimated coverage of SAV in the area surveyed was 40 to 45 %.               

September 2012 survey observations showed less SAV abundance than the June survey, and overall percent coverage was lower than previous years.  Four species were identified and are listed in order of abundance:  wild celery, redhead grass, Eurasian watermilfoil, and curly pondweed.  Most of the SAV beds were noted in between the jetties and the beach and from the jetties to Drum point.   

Average Secchi depth during the September SAV survey was 1.5 ft.  Water depth ranged from 2.1 ft. to 6.3 ft.  Overall estimated coverage of SAV in the area surveyed was 15 to 20%, noting the highest percentage between the beach jetties at 30% abundance.

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2012 SAV survey results - general overview

November 1st, 2012 · Posted by Robert Orth· No Comments

Nov. 1, 2012

Greetings SAV friends and colleagues!  It looks like we dodged a bullet with Sandy down here at VIMS.  We got a bunch of rain but most of us kept power throughout the storm.  I hope you made out okay.  Thankfully we completed the aerial photography of the entire Bay for the 2012 SAV survey before this storm hit.  We will be able to produce a baywide SAV coverage number for 2012.

Without going into a lot of detail river by river (that will come later when we finish the baywide mapping), here are a number of highlights for the 2012 survey (both good and bad):

The large SAV bed on the Susquehanna Flats made a good comeback in 2012 and appears quite robust in the photos, although the total area will definitely be less than what we noted a couple years ago.  On the downside, SAV was pretty much absent in the nearby Elk, Bohemia and Sassafras rivers.

SAV in the western MD tribs was highly variable, with abundant beds in the Severn River but pretty much gone in the Magothy River.

Widgeongrass populations once again exhibited some wild and enigmatic fluctuations baywide.  It was abundant in the Mobjack Bay area in the lower bay.  It re-appeared in the mid-Potomac in St. Clements Bay where we had not seen it since 2005.  It was present but down quite a bit in the Choptank, but just north in Eastern Bay, MD, we did not see any. Nor did we see much in the Fleets Bay and Dameron Marsh area in Virginia waters.  And in other areas it seemed to hold its own, e.g. the Honga River.

Eelgrass, in general, seems to be making a very slow recovery from the 2010 dieback, but in a few places where VIMS conducts some transects, eelgrass was either absent or very low in abundance. We are closely studying the long-term decline in this species that has been punctuated by dieback events in 2005 and 2010, coupled with moderate recovery.

An interesting story continues to develop in the mainstem tidal fresh areas of the James River where we have once again seen more fringing beds than the year before.  Most of what was noted this year is N. minor.

Hurricane Irene and Tropical Storm Lee prevented our efforts to map the upper Potomac in 2011. The 2012 imagery reveals a significant decline in that area that is probably at least partly due to the turbidity caused by those storm events

SAV in the MD Coastal Bays is continuing its downward trend over the last decade; however, just south in the VA coastal bays, eelgrass continues to do very well and is increasing in coverage.

So, in summary, 2012 had some good news and not so good news.  The hot spots for SAV growth in 2012 are the Susquehanna Flats, mid-bay islands from Tangier to Bloodsworth, the Mobjack Bay and Poquoson Flats.

We are still processing all the 2012 imagery and will be publishing the imagery for each area on the SAV interactive map (http://wwww.vims.edu/bio/sav/maps.html) as soon as it is available. We also publish SAV maps for each USGS quadrangle area as they are photo-interpreted. These are available at http://www.vims.edu/bio/sav/sav12/quadindex.html.  We remain on target to have baywide and segment SAV numbers by March 1.

Finally, with regard to any possible effects of Hurricane Sandy on SAV, we will not know anything definitely until the 2013 survey.  However, our gut feeling is that the storm effects on SAV will be minimal.  The storm occurred pretty late, well after most species have completed their growth cycle, and wind effects may only be in those areas that were exposed to the strong winds out of the NE and NW. The Conowingo flows right now, while high, may not be too much of an issue for SAV in that region. These high flows are also two months later, and less, than what we saw for Irene and Lee.  The last good satellite photo on Oct. 22 still showed some SAV there.  So now we wait.

Cheers
JJ

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