While it is not uncommon to observe the random eelgrass seedling or two in or adjacent to openings in the meadows during winter and early spring, it is a rare occasion when we find large numbers of these small shoots blanketing the bottom. While diving near Stonington Pt., CT last week, we observed one of these rare events. I had wanted to drop into this site to observe the natural meadow and compare the growth there to what we had observed earlier in the day at our Little Narragansett Bay, CT. test plots
. However, what I wasn't prepared to find were the incredible number of seedlings.
As I swam through the meadow I saw several large open areas; we usually call these areas "blowouts", but there was no indication as to how these formed as I don't think this site sees heavy wave energy and waves that could scour bottom. When I dropped into the first open patch I was amazed when I saw all the seedlings carpeting the bottom. They were all roughly the same size and seemed to be grouped in waves corresponding, more or less to bands of small gravel amongst the otherwise sandy bottom.In my nearly 20 years of diving in eelgrass I have never seen so many seedlings in one area except for possibly several years ago when a meadow in at Noyack Creek in the Peconic Estuary recruited from seed after loss all of the adult shoots the previous year (these seedlings all eventually died that summer and the meadow was lost).
In addition to the open patches there were also a number of seedlings growing in and amongst the adult shoots near the edge of the openings (see above). I did not spend time looking further in the vegetated areas to see what the extent was, but I think the seedlings were mostly limited to the openings and near the edge of the openings.
It will be interesting to visit the same meadow later this year to see if the seedlings survive. There are any number of reasons why the seedlings can be lost here not the least of which could be overcrowding and competition for space and light. Other factors could be bioturbation and other disturbance.
The main question I have is why the seedlings recruited here so well in the first place?
Last week we visited our test plots in Little Narragansett Bay (the CT side near sandy Point) to see how our plantings, that were part of our National Fish and Wildlife Foundation, Sound Futures Fund project, had overwintered. Our project partner at UCONN, Dr. Jamie Vaudrey
had been out on the site the week prior and reported finding plants at our GPS coordinates while searching with an underwater video camera, but we definitely needed to get in the water to see things first hand.
The plants that we used to establish these test plots were produced as part of one of our volunteer "Marine Meadows
" events that was hosted by Save the Sound
and Mystic Seaport
last year. Save the Sound have been great partners in organizing these land-based volunteer events within CT to support our eelgrass restoration efforts in LIS. As you can see from the picture above and the one below, things are looking very good here so far for our LNB test plots.
One interesting thing we observed while diving the site was the deep brown color of the water. We had seen this somewhat last year, but nothing like the dark brown color we witnessed on this day. Apparently the recent rains have flushed all the lignins and tannins into the Bay from Pawcatuck river. We had a pretty good idea of what we were in for as we motored through the channel as our propwash was a rust brown color. Note that I had to color correct the pictures a little to take some of the brown out as the original photos were even browner than what I observed while in the water.
As we usually do, I was hoping to do some counts to calculate percent survival for each plot, but it was a little hard to distinguish individual plots since the plants had spread from their original locations and a couple areas were missing, probably from Horse Shoe Crab feeding activity that was obvious in area. There was even a HSC almost entirely buried next to one of the plots. I think we were actually lucky that the HSC's hadn't dug up even more of the area...
Despite my inability to get any hard numbers on this dive, overall, the plants looked excellent...a little taller than I was expecting, but great. I was surprised to see that some of the larger shoots approached a meter in length. I also noticed a number of laterals growing from the base of the plants which is a very good sign for the coming months. Another interesting thing about these plants is that they were entirely free of epiphytes. We usually don't see this.
In order to see how our plants compared to natural plants in the area, since we don't have much experience in CT waters, we decided to drop in on a meadow to the east side of Stonington Point, CT, where we had observed grass last year. Here we found very similar if not identical looking shoots(see below) except for the fact that the density was much higher which is to be expected. Another difference was the fact that the water was not quite as brown as in LNB.
You can also see that the macroalgae gathering near the base of the shoots appears to be nearly identical to what we observed in LNB as well. Again a good sign indicating that things are a normal looking as they can be for this time of year.
We should be back up to LNB at least a couple more times this summer to track the progress of the plantings and we hope that everything makes it through July and August when established plantings can fail due to heat stress and other factors. Hopefully, this won't be the case here. If we do get good summer survival, we will definitely be looking to expand on this site to create a large meadow.