Aerial and Field SAV Observations

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6/27/13 Aerial Update

June 27th, 2013 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.

Tags: Aerial Updates · SAV Observations

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