Saturday, August 30, 2008
Well, yesterday I worked on the barge - its a boat built by S.P.A.T. volunteers working with the Cornell Cooperative Extension of Suffolk County. It is used mainly for the scallop restoration work, and is equipped with a motorized winch and a star wheel for hauling up lines weighed down by hundreds of lantern nets full of scallops.
This time of the year, the majority of scallops in the nets have spawned at least once, so they need to be relocated to make room for the next batch of scallops to grow-out before overwintering. It can be a labor intensive process as the nets are heavily weighed down by fouling organisms, in particular sea squirts. It is essentially pulling up a net full of scallops, as well as hundreds of little water packets (the squirts) so the nets get pretty heavy. Then, most of the squirts need to be knocked off before the bags can be opened and the scallops dumped on deck, so it is also a very messy process, and sometimes, not very easy as an invasive sea squirt, Styela clava,
have very strong attachment points to the nets and to shells within the nets. Once the nets are cleaned and the scallops dumped onto deck, they need to be released to the bottom.
Some of the scallops are pretty fouled (the latter two were collected a day earlier),
but it adds to the camoflage for the scallops on the bottom. The nets also often have lots of little guests in them, including hundreds of grass shrimp and mud crabs, spider crabs, cunner and tautog, and even sculpin.
Sometimes we get pipefish and seahorses from the nets but this is more rare. Additionally, some of this years seed (scallops from earlier spawns this year) have set on the nets and grown very well.
All in all, it was a nice, messy day on the boat with some interesting things to see, including this awesome schooner, the Mary E, on our way home.
Wednesday, August 27, 2008
Well, I just talked about Monday's work diving - searching and collecting the recruitment squares, and then replacing them. But we ended up finishing that fairly quickly this time (only a couple of hours) and we had a prospective student for next fall (09) with us - a former Master of Science student from Dauphin Island Sea Lab who currently works for a consulting firm in Florida and deals with habitat restoration and monitoring, and inparticular, seagrass restoration and monitoring. The day ended earlier than usual at my field site, so we stopped at a couple of other spots on the way home to do some fun dives, and so I could show my friend around.
First, we stopped at the long lines in Orient Harbor (which I talk about here in my first ever post.) Now the long lines essentially are just that, rows of lines with anywhere from 100-200 or more lantern nets hanging so that the scallops are suspended mid water column - out of the reach of predators on the bottom and not exposed to air from above. (On a side note, lantern nets make great closet additions - hanging a five tiered net or two in your closet eliminates the need for a dresser, for example, and they are good to store food in as well). Now I mention the long line site, bc I have dove on it quite a few times this summer and it always creeps me out - the water is murky (it is Long Island, afterall) and you just see these large dark objects come into view just hanging there, motionless,fouled with all sorts of algae, squirts, tunicates and sponges.
When I am working with the nets, opening them under water, reaching in to sample scallops
, sometimes I get spun around and another net hits me in the back, or a line from the bottom of the net hits my fin - this always freaks me out just a bit.
Either way, they are cool to see so we went there, looked at the nets, where I tried to get a picture of some of the fouling organisms.
We also went to the bottom near the nets to see any scallops released near the nets
and to just look around and see what we could find - and we had quite the find - a mantis shrimp, just walking around, and at one point looking right at me! Pretty awesome.
Next we stopped over at a healthy Zostera bed at Hay Beach on the northeast side of Shelter Island, especially since our visitor is particularly interested in seagrass. We saw some pretty cool stuff there as well, including juvenile flounder
just swimming around. There were also cunner, tautog, and pipefish.
We also found a few whelks and a scallop spat!
And of course, lots of silversides following us around, as we were stirring things up. Now silversides are nearly impossible to catch with the camera, at least for me, since they are almost transparent and blend in with the water, plus they swim around so fast, but I was able to capture a few of them here (oh and that out of focus blog at the center in the upper half of the photo is a comb jelly, or ctenophore).
All in all a fairly good day!
Tuesday, August 26, 2008
So, a few posts back I was disappointed in the lack of scallop spat on my mats and in Hallock Bay in general. We had not really seen any in our collectors which we use to monitor spat in any of the collections, and so I was not so upset that I wasn't finding them on my mats, just figuring they weren't around. I was a little worried though, since scallop recruitment is a part of my research, and I was already thinking about possibilities of new locations for next year. I was ready to give up on the recruitment thing all together, since it is a lot of work to make the recruitment squares, to search for the squares within the mats, and to put new squares back on, not to mention I didn't want to keep wasting fuel for fruitless boat trips to my site. However, after much deliberation, I decided to make a new set of squares over the weekend to put one more set out there, just to be sure I wouldn't miss it.
Well we went to the site on Monday to collect my 3rd set of recruitment squares and to replace them with the 5th (and final) set. I also keep a set of spat collectors at the center of my array to make sure scallops are recruiting to the area using a known method for sampling them. I always process the spat collectors first, just so I have an idea of what to expect on my squares. Guess what?
Scallop spat in my collectors!! This was exciting. It wasn't a lot, only 16 total out of 3 bags, but I honestly didn't think I would see any. I still wasn't sure what to expect on my mats, but at least I was happy there were spat in the area. After processing all the recruitment squares, I did have spat on the mats! Success!! Well, kind of - we only found 4 total spat on the squares, not quite numbers that I can use for any kind of stats. However, now I know that if there are spat in the area, they will potentially settle on my mats, which was very refreshing to find.
Oh, and there is better news, the spat that we found was mostly small - 2-4mm. This is good, because it means the spawn happened relatively recently, and will probably show up on my next set of collectors. Second, and more exciting, is what we found today - in our spat monitoring we have 5 sites within Hallock Bay where we have sets of collectors, and we found spat at all of them, and in decent numbers (some bags over 20 scallops) and again, many were small. So I am keeping my fingers crossed that I will see much better numbers on my mats during my next collection!
Sunday, August 24, 2008
Friday, August 22, 2008
Well, this week was a big week of sampling for me...
Not only was my first field sampling for the scallop growth experiment in the grass mats, I also planned to use this week as a scallop predation experiment week... The scallops for growth were measured two weeks ago, transported to the site, placed into white spat bags, and set at locations in my artificial seagrass array...
I was pretty excited going forward with the growth experiment because it worked out so well last year, and I almost doubled the number of scallops this year that I used last year... So you could expect why I was looking forward to this week, T-2 weeks, to see how my scallops were doing...
DISAPPOINTMENT!!! I would have to say using back of the envelop calculations, approximately 30% of my scallops did not survive to this sampling period! This was particularly shocking to me, since I only lost about 10% of the scallops I used last summer during the entire 12 week growth experiment... Of course, I was bummed... We measured the dead ones anyway, hoping that after I come up with a growth rate at the end of the experiment, I could approximate when they might have died... However, quickly looking at the numbers indicated to me that most of them probably died the day they were put out in the field... I suspect this is more likely the case, and I blame myself for this... There were probably some issues in transporting the juveniles from the hatchery facility to the field site, and then the time it took to get all of them into bags and situated onto their respective sites, they were probably out of water too long... This wasn't such a problem last year, but again, with almost twice as many scallops to place out in the field, almost twice the amount of time is needed to actually put them all out... So, suffice it to say I will be putting out some more scallops the next sampling to make up for the loss...
The second experiment worked out much better this time... Last year I tried this same predation experiment with no success - problems recovering tethers, loss of scallops during transport, tether tangling, screwy and missing data points... So I tinkered with and refined my methods for this year, and WOW!!!
Things worked out so much better this time around... Predation was as expected and I actually pseudo-observed a scallop being preyed upon...
After putting out all my tethers on Tuesday, 8/19, I went back with my camera to get some pictures, and when I went to the unvegetated tethers, I noticed a fishing line going into a half clam shell... I thought it was weird that the scallop would swim into there and byss, so I tried to pull the line, but it wouldn't budge... Upon further inspection, I saw a mud crab under the shell with the scallop shell, now in two halves... I tried to get a picture...
Anyway, this was exciting that it happened so quickly (if I had to guess, I would say within an hour and a half after release)... And I am very pleased with my results this time around... There are still some bugs to work out, namely preventing scallop tethers from tangling with each other during transport, but I look forward to running this experiment again in the fall...
Additionally exciting is that I observed adult scallops in or near my mats again this time!!!
And, a fellow diver, Andrew, observed some small scallop spat (probably in the 7-10mm range) on my mats, and if you remember from previous posts, I have been very disappointed for the lack of scallop recruits to my mats, so this was very good and welcoming news, and so this means that my recruitment experiment is starting to look up!!!
I also saw many fish again this time - including weakfish (probably about the size of the one in the photo from the web) for the first time, juveniles of course, and the usual suspects of pipefish, sticklebacks, tautog and cunner, and possibly a black sea bass, but visibility wasn't great and whatever it was swam away very quickly... Oh, and I saw this big spider crab who tried to get me!!!
By the by, check out Chris Pickerell of Seagrass.LI's blog here... He's got some pretty exciting stories going on, including pregnant seahorses, and horny (read:territorial) male sea robins...
Oh and stay tuned for slide shows from this week...
Tuesday, August 5, 2008
Well, I went to remove the second set of my recruitment squares on Monday with hopes for better results than last time. Well, unfortunately, there was no scallop spat again on my mats. NONE!!! This is becoming a little disappointing. I understand that finding spat on grass is like finding a needle in a hay stack. But I should see something, anything. out of 72 squares, 360 shoots, and only 1 Crepidula fornicata and 1 mud crab. WHAT? In my "control" spat collectors, similar to the ones we use for the monitoring efforts, I didn't get any scallop spat either, and didn't get anything else other than mud crabs!!! This is not good. Whats worse, we had another round of the spat collectors and not a single scallop spat in any of the collectors placed in Hallock Bay, and when we monitored our free planting site from last winter, we only found 5 scallops in 24 square meters. I am worried that I won't get any spat on my mats at all, and this means I might have to find a new location to look at recruitment. On a better note, I did place out 680 scallops for monitoring growth on bare sand, at the patch edge and in the patch center. That should go better, at least I hope.