Aerial and Field SAV Observations

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09/01/11 An SAV Update

September 2nd, 2011 by admin · No Comments

Greetings SAV friends and colleagues! It looks like another summer is about to end and as in past years, there seems to be both good news and not so good news with SAV in the bay. We have made good progress in acquiring photography. We completed the entire lower bay by the end of June, and coastal bays by early July. We were also making good progress for many of the lower salinity regions of the bay and tributaries, but Irene has put an abrupt halt to further efforts until the water clears.

Our staff is processing the imagery and will be adding it to the interactive map (http://www.vims.edu/bio/sav/maps) as it becomes available. Our SAV blog (http://thumper-web.vims.edu/bio/sav/wordpress/) is up and running and we already have a number of interesting observations. Please let us know what you are seeing out there! Various Riverkeepers have really been a big help in recent weeks.

Here are some observations from the areas that we have photographed so far:

SAV abundance, both eelgrass and widgeongrass, in the lower bay is down quite a bit, most likely a result of the effects of the hot summer in 2010. It looks like we may be down as much as 40% from 2010 when we acquired the photography just prior to the onset of that heat spell. The dense beds in many of the lower bay locations were still present, e.g. Poquoson Flats, Mobjack Bay, Tangier and Smith Islands, but there were big changes throughout the region. Interesting, at the same time, widgeongrass had some robust and very dense flowering shoots in many areas of the lower bay.

SAV in the MD coastal bays looks good except in Isle of Wight and Assawoman bays. Here, widgeongrass appears to absent in many places. In the Virginia coastal bays at our restoration sites eelgrass beds are once again doing really well.

James River (flown Aug 1 and 16) – while we have noted that SAV has colonized many of the smaller tributaries (e.g. Powell’s and Herring Creek near Hopewell, and the Chickahominy River has an abundance of SAV), for the first time since we started the survey back in 1978, SAV is present in the mainstem James. The bed is located above the mouth of the Chickahominy River along the James north shore off Tyler Creek just up from Sturgeon Pt. We were lucky to have the James Riverkeeper check it out and he noted this large bed, about ¾ mile long and probably 100 yards wide, was dominated by Naiads. And Queens Creek, up from this bed which had little last year, was loaded with SAV (both hydrilla and naiad) right at the mouth of the creek. We also noted a small bed on the mainstem off a marsh adjacent to Presque Isle.

Pamunkey and Mattaponi rivers (flown Aug. 1 and 16) are again loaded with SAV in the usual places. All prior years’ ground observations have shown it is mostly hydrilla.

Choptank River (flown Aug. 23) – there is definitely more SAV in many of the tribs (Harris and Broad creeks) than we have seen in previous years. We have heard from a number of sources, especially the riverkeeper Drew Koslow, that widgeongrass has re-appeared in places it has not been in years.

Mainstem from the mouth of the Choptank to Eastern Bay – there is lots of SAV from Harbor Cove to Claiborne. We did not detect any SAV off Poplar Island.

Eastern Bay and tribs (Miles and Wye rivers) (flown Aug 23) – there is much more SAV than in previous years in many areas – probably all widgeongrass.

Eastern Neck and Chester River – WOW!! The large shoal along the western side of the area is full of SAV – I haven’t seen this much since 2005, and many of the small coves in and around Eastern Neck (see photo) have SAV’s. Chester River proper has very little except at Robins Pond and a few other locations.

Potomac River - lower sections from 301 bridge to mouth (flown July 28) – there is very little SAV but we have not gotten imagery for the St Mary’s where most of the SAV was in the last few years. SAV has returned to Nanjemoy (flown Aug. 24) but only the upper part. Potomac Creek is loaded with SAV but appears to be down in Aquia Creek. The mainstem Potomac from Maryland Pt to Mattawoman and Aquia Creek to Neabsco Creek looks okay although SAV in some places appears to be less than in 2010.

Western shore tribs (flown Aug. 24) – the only river that appears to have any significant SAV is in the Severn although its abundance is down. SAV in Shallow Creek (see photo) looks good except it is down from last year although Peter Bergstrom reports greater species diversity this year.

We would love to hear from more of you if you have been out in the shallows!

Cheers

JJ

Tags: Aerial Updates

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