Aerial and Field SAV Observations

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Final 2010 Update - it’s all about location, location, location!

October 1st, 2010 by admin · No Comments

SAV Friends and Neighbors:

The 2010 SAV monitoring is just about complete as we have flown all the major lower salinity and tidal fresh water areas with SAV over the last month and a half. The lack of rain (well, just up to this week that is!) and some great weather in early September proved to be quite favorable for getting good aerials of much of the Upper Bay and tribs. Working closely with Todd Beser and the controllers at APG, we also lucked out with some great photos of the APG area a few Saturdays ago.

Depending on where you are in the bay, the SAV picture is pretty different. For example, the SAV on the Susquehanna Flats is amazing; it’s holding its own in the Mattaponi & Pamunkey rivers and Dundee Creek; and is pretty terrible in much of the mid-Bay (e.g. Eastern Bay or the lower Choptank River) and lower Potomac River. Widgeongrass populations this year remain enigmatic. In some rivers systems this species has been quite abundant (e.g. Rappahannock River and the Reedville, VA area) while in other areas it has declined or actually disappeared (e.g. St. Mary’s River and the large beds just north in the Potomac in Breton and St Clements bays). We have seen this pattern repeated in past years which has not yet been fully explained.

The Susquehanna Flats continues to be the SAV story of the day – WOW!! I had a chance to go out with the SAV Workgroup in August and it is truly amazing to have SAV extending as far as you can see in every direction. I was out there in the ‘90s with Stan Kollar and there was almost nothing on the Flats except the occasional small patch of milfoil – what a turnaround! It is one thing to see these beds from our photos or from the MODIS satellite. It’s a whole other ballgame when you have your face in the grass! Wild celery with leaves almost 6 ft long is a sight to behold!

However, one other story has unfolded this summer. It does appear that eelgrass here in the lower bay has suffered another setback this summer due to the really hot summertime temperatures. While the springtime aerial survey showed abundant SAV and has documented the continued recovery of eelgrass from the 2005 dieback, many of these beds now have almost no eelgrass present except for a few small shoots. How this plays out in 2011 will depend on how much vegetative material is still surviving and the seed crop produced in 2010.

Here’s a quick summary of what we see on the imagery. We’ll have a more detailed look, with area numbers, when we complete the GIS analysis.

If you missed my first update for much of the lower bay, you can find it at:
http://thumper-web.vims.edu/bio/sav/wordpress/index.php/archives/826#more-826.

Also, if you want to see what is happening so far in the 2010 mapping and SAV numbers for quads completed so far check:
http://www.vims.edu/bio/sav/sav10/quadindex.html.

Lastly, we have started to place much of the 2010 imagery on our interactive site:
http://www.vims.edu/bio/sav/maps.html
However, the mapped beds for 2010 will not be placed on the site until we complete the survey. If you have questions on what we are seeing so far, give us a shout.

Cheers
Bob Orth ‘JJ’

Virginia (minus the Potomac River)
Upper Mattaponi and Pamunkey Rivers – the upper tidal freshwater rivers are loaded with SAV again with our field surveys showing these beds being essentially mono-specific hydrilla. We have only found one small bed of wild celery in the Mattaponi.

Upper to Middle James River - we once again see no SAV in the mainstem James. However, almost all the creeks up to Hopewell, including Grays, Upper Chippokes, Wards, Powells, Herring and Powhatten creeks, had a fair amount of SAV present. The Chickahominy, one of the larger rivers entering the mid-James, had abundant SAV. Our field surveys have been finding only two species though: N. minor and hydrilla. We are still awaiting the first signs of any SAV in the mainstem given their presence in all these creeks.

Upper Rappahannock River – we are seeing more and more SAV around the Port Royal region, which probably is hydrilla, based on what we identified in past years.

Maryland (minus the Potomac River)
Little Choptank River – we see almost no SAV here. However, in the Brannock and Trippe bays, just above the Little Choptank, there are some small beds but nothing like what we have observed in the past.

Choptank River – the river is pretty much devoid of SAV except for some small beds in the area of Cooks Point Cove and Chapel Creek. Creeks along the north shore have almost no SAV this year.

Eastern Bay – as in the past few years, the only place we see SAV is around Marshy Creek near Kent Island Narrows and on the broad sandy shoals along the eastern side heading towards the Choptank. What a contrast from not too many years ago when the whole bay was full of SAV!

Chester River area – The Chester is essentially devoid of SAV except what is present in Robins Pond. Around Eastern Neck Island there are small pockets of SAV but only in Hail Creek and Tubby and Half Pasture coves. Along the mainstem above the Chester, the only significant beds appeared to be around the Rock Hall Harbor area.
Patuxent River – there is one fringing bed of SAV along the north shore down from Solomans. But the rest of the river is devoid of SAV until you get into the tidal freshwater areas where SAV has been present since the 1990s. It remains in many of the same areas as previous but some of the beds do appear to be reduced in size this year.

West, Rhode and South rivers - we do not see any SAV.

Severn River – SAV is abundant in Round Bay but it does appear to be less than in 2009.

Magothy – this river has essentially lost almost all its SAV. While Peter Bergstrom (the wonderkid of SAV surveying for that river) has found a few more spots with small pockets of SAV, we see only two small areas with mappable SAV. Peter Bergstrom has done quite a few ground surveys and they are available at:
http://thumper-web.vims.edu/bio/sav/wordpress/index.php/archives/author/pbergstrom.

Patapsco – not much except for very well developed beds in Shallow Creek, also visited and reported on by Peter Bergstrom
(http://thumper-web.vims.edu/bio/sav/wordpress/index.php/archives/author/pbergstrom)

Back and Middle River – not much in the Back but SAV remains present in quite a few places in Middle River.

Gunpowder River – SAV is really abundant in Dundee Creek, and in portions of the Gunpowder noted in 2009. There are a few locations where it appears more than in 2009 especially along the mainstem shorelines.

Bush River –appears to be a bit more SAV than 2009, and dense in a few coves. SAV is more extensive in lower portions of Romney Creek and much of Little Romney Creek.

Susquehanna Flats and APG area – WOW!! The SAV beds continue to look fantastic and remain robust and incredibly thick.

Elk River – thick beds all the way to the head

Sassafras River – SAV beds remain dense in the lower portions.

Potomac River (both MD and VA)
The Potomac remains a system of contrasts. There is almost no SAV in the lower portion from the mouth along both shorelines to just above the 301 bridge. The only system that still holds some SAV is the St. Mary’s, and abundance here appears down from 2009. In the transition zone, there are some small beds in Port Tobacco Creek but very little in Nanjemoy Creek compared to just few years ago when both these systems were loaded with SAV. However, SAV becomes quite abundant from Potomac and Aquia creeks all the way to the Woodrow Wilson Bridge along both shores. For some unknown reason, there is still almost no SAV on the big shoal area in the middle of the river surrounding the bridge even though the bridge construction is done. Above the bridge there is little SAV compared to past years when it was visually abundant along both shorelines. Now, it mostly occurs in small pockets along the western side just below the airport and then up around Roosevelt Island.

Tags: Aerial Updates

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