Aerial and Field SAV Observations

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Abundance of Chesapeake Bay’s underwater grasses rises 24% in 2013

April 23rd, 2014 · Posted by admin· No Comments

Widgeongrass expands in mid-Bay, eelgrass sees modest recovery

An annual survey led by researchers at the Virginia Institute of Marine Science shows that the abundance of underwater grasses in Chesapeake Bay increased 24% between 2012 and 2013, reversing the downward trend of the previous 3 years. The increase reflects an upsurge from 48,195 acres to 59,927 acres.

Read more about the 2013 survey results…

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More Eelgrass in South Bay

April 3rd, 2014 · Posted by Robert Orth· No Comments

Earlier I mentioned that as were mapping the South Bay bed from the 2013 photos we were stuck by the large number of ‘dark specks’ on the photos in an area at the south end of South Bay which we had not mapped yet.  These specks were in an area adjacent to an area we had been mapping and had been confirmed as grass.  The specks looked like grass patches as when we examined 2 sets of photos, one taken in Oct and the other in Nov., many of these specks present in Oct. were still there in Nov. When we created the polygon the area was around 450 acres which would be a significant increase to that Bay.

So yesterday, Corey, Barry and I checked out a number of spots in that polygon (see image on right) to confirm what we suspected were grass patches. And sure enough every spot we checked was eelgrass!! Patches ranged from small ones of 10-20 cm in diameter to large ones, maybe up to 2 m in diameter. In several places the patches were dense perhaps covering 25% of the area but in general the area will be mapped as cover class 1.  The plants were short (remember water temperatures have been below 10C so far) but shoot densities were high and almost all had flowering shoots meaning they were at least 2 years old, and some maybe 3 or 4 years old.  I also noticed a lot of seedlings in each area. What surprised me is that in one area (spot #2) we motored all the way west to the marsh edge on Mockhorn Isl. and noted many patches that most likely were 2 years old but because they were so sparse will not be seen in the photos.  And these were in an area that I thought we may not see eelgrass because of some macroalgal issues we have noted before.

These observations are significant in light of the fact that last year, the spring was incredibly windy and water clarity was terrible and had prevented us from getting out photographs last spring.  Yet these plants made it through last year and again many were at least 3 years old based on their size.

So the bottom line is that this South Bay bed continues to spread and expand which hopefully bodes well for our scallop work.

Last, yesterday was absolutely beautiful – warm and clear skies!  The water cleared up as the tide dropped and we could see all these patches very easily from the boat. The spread of patches in some areas was truly amazing! This was a great way to start the field season!  It was hard to leave and head back home.

Cheers

JJ

PS – I even saw a redfish in about  a foot of water although Barry did not believe me – I think he was jealous because he did not see it himself!

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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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SAV in Hunting Creek

September 17th, 2013 · Posted by admin· No Comments

Chris Jones, George Mason University (Quad 034)

Here are two views of Hunting Creek (large half-moon shaped bay on the Virginia side of the Potomac River, just downstream from the Woodrow Wilson Memorial Bridge), at very low tide. These two views basically face each other across Hunting Creek:

  • View 1 is looking South from the George Washington Memorial Parkway Bridge toward Belle Haven Marina (inorganic flats in the foreground, SAV in the background)
  • View 2 is looking North from Belle Haven toward George Washington Memorial Parkway Bridge (low profile, concrete arches) (SAV in foreground and midground, inorganic flats barely visible in background).

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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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Ruppia in Cherrystone Inlet

August 5th, 2013 · Posted by admin· No Comments

Anna Murphy (Quad 133)

We checked out three sites in Cherrystone last week. The site on the southern side of the creek had small patches of ruppia, ~1m in diameter. The site closer to the mouth on the north side was the most dense site, with 100% coverage, all the way up to the surface at probably a meter deep.  The northwest site was patchy.

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SAV on the Susquehanna Flats

July 31st, 2013 · Posted by admin· No Comments

Cassie Gurbisz, UMCES (Quad 003, 009)

We’ve been up to the Flats quite a bit this summer–most recently yesterday. The water clarity seems to be very good inside the bed. It looks like the plants are doing pretty well. It’s hard to say whether it is better than last year across such a huge area but I did notice that the layer of highly resuspendible material (which we assume was left-over from Tropical Storm Lee) that made plant sampling difficult last year is not there this year. There doesn’t seem to be as much filamentous macroalgae around the DNR sensor site but some other parts of the Flats have patchy areas of algae cover where there wasn’t last year. It seems like the plants are following more or less the same growth pattern as last year–fairly sparse in June and still not quite peak biomass as of yesterday.

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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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Hard shell bottom near Haynie Point

June 26th, 2013 · Posted by admin· No Comments

Chip Neikirk, VMRC (Quads 106)

While conducting their regular field work in the Great Wicomico yesterday afternoon, Betty and Bubba stopped by the sites off the mouth of Whays Creek near Haynie Point to obtain some depth measurements and try to gather some information on the bottom type.

Based on their findings, it appears the areas we are seeing are areas of bottom where oyster shells have been placed. This corresponds with what Jim Wesson told me last week about the area closest to points 11, 12, and 13. He said both VMRC and the Corps had placed shell in that area and that area is within public oyster ground (Baylor Ground). The other areas are located on privately leased oyster planting ground and Jim indicated he thought the area was being worked. Betty’s observations regarding hard shell bottom, depth and extensive marking seem consistent with that activity.

Point-ID Longitude  Latitude
11          -76.3101  37.83051
12          -76.3102  37.83058
13          -76.3104  37.8306

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