Tag Archives: oyster spat

Day 4: October Oyster Push “Sweet Boat”

Rob Diaz de Villegas WFSU-TV
David Kimbro’s crew has been split into two teams, the Net/Trap team (N/T) and the Tile team (TI). For a closer look at how David’s team nets and traps larger fish and crabs, click here. To learn more about what the Tile team will be doing, click here. And if you click On the Reef under categories in the sidebar, you can track David’s progress over the course of this study.

Monday, October 25- Both teams in Saint Augustine

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That grey spot (dead center) on the shell is spat. After landing on existing shells, they'll build their own and expand the clump.

IGOR chip- biogeographic 150When I got to St. Augustine, David was chiseling out shards of shell containing oyster spat (baby oysters) from clumps so that he could glue them onto tiles, as he described in Friday’s post.  I got a good look at what spat actually was.  You can see it in the photo here, basically a small oyster with no shell, seeking out a hard surface (often another oyster’s shell) upon which to settle.  David stayed behind doing that as the rest of his crew, and our crew, piled into the boat for this evening’s activities.

This new experiment- placing tiles with the same number of oyster recruits at all sites on every reef across the study- will give them a more precise picture of how young oysters survive at each site.  It also means a lot of extra work, as the spat that goes on the tiles has to be from the specific location to be entirely accurate- spat is harvested one day, immediately chiseled off and made into tiles and placed on the reef, in the span of about two days.  And this is in addition to the other sampling and trapping.  The previous tile method worked fairly well for the NC and SC/GA teams, but for the sake of being consistent, they’ve also had to adapt this method (while cursing David Kimbro’s name).

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Crown conchs in St. Augustine making a snack of an oyster.

As previously noted on this blog, the reefs did have plenty of crown conchs crawling on them.  David and Tanya have also started noticing Atlantic Oyster Drills, a smaller snail we don’t see in the Gulf.  I’ll look for some tomorrow and get a photo or two up.

8:00 AM- Hanna and Randall (N/T team) retrieved the nets that they set last night in Cedar Key.  This is low tide work, as that’s when it’s best to empty the nets.  They got to their first reef after the vultures did, losing a bit of their catch but still able to identify some species from the fish heads left behind.

1:00 PM- Hanna headed to Saint Augustine and Randall headed home.  As Hanna was gassing up the truck and boat, an elderly gentlemen circled the boat, in awe of David’s creation.  Eventually, he said, “sweet boat.”

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A sweet boat.

5:00 PM- Deploy nets, take water samples, and reference water level.  The two teams combined activities that would have kept them out past dark, and finished just as the sun was setting.  They then helped David glue spat onto tiles for another hour or so before heading out to dinner.

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That was the day.  As you see, field work involves a lot of rethinking (as in the tile experiment), thinking on your feet, dealing with circumstances (vultures eating your catch), and coming up with unusual solutions (refitting your boat in a way some might find strange).  It’s pretty late now (as I type this, even though I plan to post this in the morning).  Time to head to bed so that I can get up and shoot that sunrise.

Tide Times and height (ft.) for Cedar Key, October 24, 2010
Low- 10:oo AM (-0.3)
Tide Times and height (ft.) for Saint Augustine, October 25, 2010
High- 1:35 PM (5.3)
Low- 8:41 PM (0.6)

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The Magic

Dr. Randall Hughes FSU Coastal & Marine Lab
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Randall gets back to her roots, placing traps on a reef with Hanna.

IGOR chip- biogeographic 150When I worked as a technician for our current collaborator Jon Grabowski back when he was in graduate school, one of his favorite sayings as we headed out to the field was “This is where the magic happens”. Yesterday and today I got to experience that magic again as I made my first visit to our oyster sites in Cedar Key. Though I spend a lot more time with plants these days, I do love oyster reefs. Maybe it’s because the first field research I did was on reefs (with Jon), or maybe it’s because of the mystique they seem to hold for nearly everyone, but it sure was fun to hear those shells crunch as I stepped out of the boat.

Of course, in addition to “the magic”, there’s also the cuts and scrapes, the no see-ums, and frustrating way that nets get caught on every oyster clump within 2 ft. But something about the reefs wins me over every time!

Enough of all the nostalgia – what did we actually accomplish? Hanna and I started about midday on Sunday, deploying traps at each of the sites. We realized as we headed back to the boat ramp that the return trip we were scheduled to make later that evening after deploying nets would have been pretty challenging in the dark, so we spent most of the afternoon seeking out a plan B. Thanks to some wonderful people in Cedar Key, we ended up docking the boat for the night at a home just near our sites! Around 6pm we headed out to pick up the traps. We didn’t find a whole lot – a few speckled seatrout and some killifish – but we were able to deploy our nets without any trouble (other than the previously mentioned no see-ums). By 9:30pm we were back at the rental house eating our frozen pizza dinner.

P1010636This morning we got up and headed back out to see what was in our nets. Somewhat surprisingly, it was all mullet and catfish! Not that we didn’t expect those fish to be there, but we thought we’d get a greater variety of species. There were also 2 red drum, 1 blue crab, and a couple of crown conchs, but mostly it was mullet, mullet, mullet.

After we got turned around heading back to the boat ramp, I was really glad that we hadn’t tried that trip in the dark last night! All in all, it was a trouble-free trip to the field, and a welcome opportunity for me to see some of “the magic” again myself.

David & Randall’s research is funded by the National Science Foundation.
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Day 3: October Oyster Push “No Nap Time”

Rob Diaz de Villegas WFSU-TV
David Kimbro’s crew has been split into two teams, the Net/Trap team (N/T) and the Tile team (TI). For a closer look at how David’s team nets and traps larger fish and crabs, click here. To learn more about what the Tile team will be doing, click here. And if you click On the Reef under categories in the sidebar, you can track David’s progress over the course of this study.

Sunday, October 24- Net / Trap team in Cedar Key

Randall places traps on a Cedar Key reef

Randall places traps on a Cedar Key reef.

IGOR chip- biogeographic 150After months of walking around In the Grass, Dr. Randall Hughes stepped out On the Reef Sunday, pitching in for some fieldwork with David’s tech, Hanna Garland. They were the Net / Trap team working Cedar Key, while Tanya Rogers is heading up the Tile team in Saint Augustine. Randall, in addition to heading the salt marsh biodiversity study we also follow on this blog, is the co-PI (Primary Investigator) on this biogeographic oyster study. With her other study taking so much of her time and David having things well in hand with this one, she hadn’t made it out into the field until Sunday.  We tagged along with her today.

This was our first time documenting this study outside of Alligator Harbor (which is located a short hour from WFSU-TV) and, actually, it was my first time on any oyster reef other than those. I noticed that the water was a little clearer- I could actually see some of the oyster clumps for a foot or so under water as opposed to not at all. Few of the oyster reefs were as large as in AH, tending more often than not to stay a collection of clumps than an expansive reef. There were also stretches where reefs had been, and all that remained were broken shells. Randall told me that these had either been harvested or that the reefs had just plain failed (Tanya recounted finding two of the Cedar Key reefs obliterated in her last post).

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Scientific equipment being used in an entirely lawful way. This machine filters the sediment floating in the water- including the phytoplankton that oysters eat.

If you take a look at the schedule below, you can see that the events are spread out based on the tide schedule; and there are a couple of days during this push where they start around sunrise and work well into the night. So there are breaks from fieldwork built into the day. I had assumed that this would be “nap time.” To my surprise, this is actually “lab time.” The water samples they had taken on our boat ride had to be filtered, and the filters frozen as fast as possible to prevent bacteria from contaminating them. They set up their “lab” in the kitchen of a condo they were renting. The apparatus they use is a collection of PVC pipes, tubing, and a motor into which they pour the liquid from clear test tubes. Randall had seen a news story this last week where some college kids were arrested for turning their dorm room into a crystal meth lab. She wondered aloud whether someone looking in their window might suspect the same of her and Hanna.

8:00 AM- Travel to Cedar Key

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Boating from reef to reef, we would see places like this where a reef had been decimated. Two of the original Cedar Key sites for this study were destroyed. These are the kinds of things that happen outside of the controlled environment of a laboratory.

12:23 PM- Deploy traps, collect spat sticks, water samples. They once again made use of the new boat, though the public boat ramp is on the other side of the island from where their sites are located. They were going to look for a boat ramp closer to their sites to save a little more time.

The spat sticks so far have only collected barnacles at all of their sites, meaning that they may have started using them past the season in which oysters spawn.

6:00 PM- Retrieve traps, High tide activities: reference water level, replace spat sticks (if possible).

9:00 PM- Deploy nets. Randall and Hanna will retrieve these in the morning before Hanna heads to Saint Augustine to meet up with David Kimbro and the rest of the crew.

Tide Times and height (ft.) for Cedar Key, October 24, 2010
Low- 9:23 AM (-0.3)
High- 3:48 PM (3.3)
Low- 9:13 PM (1.4)

Sunday, October 24- Tile team in Saint Augustine

1:00 PM- Tanya Rogers and new crew member Cristina drive to Saint Augustine.

7:00 PM- Retrieve tiles/oysters.

Tide Times and height (ft.) for Saint Augustine, October 24, 2010
Low- 7:21 PM (0.5)
We’d love to hear from you! Leave your comments and questions below:

Roctober!

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- biogeographic 150I went to graduate school in northern California. Locals along the coast of NorCal used to refer to the month of October as Roctober because it was the most beautiful time of the year.  Well, I think the Forgotten Coast should also be privy to this monthly description because things have been beautiful around here this month.  Looking at the oyster reefs, I get the sense that things are really starting to get busy in there.  But I wonder if the ecology on oyster reefs in NC is starting to slow down.  Where are predators really having a big effect? We shall soon see.

For the past week, we have been trying to figure out how to do a lot of ambitious seeing and learning on all of our reefs.  All three teams (i.e., NC, SC/GA, and FL) need to not only sample fish and invertebrate predators on reefs (for the second time and in the dark…all because of the timing of tides in the autumn), but each team also needs to simultaneously squeeze in an experiment.  Oh, I just remembered that we also need to pay attention to other things that can explain oyster patterns: oyster food in the water (phytoplankton), water temperature, tides, and sediment properties.  So, add those to our to-do list as well!

Because this will be a ton of work to do in a short amount of time, we are sending a new crew member of the Florida team (Alicia Brown) up to help out the South Carolina/GA team.  We are going to send her up with a video camera, so it will be fun to get a glimpse into their lives over the next week.

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Jon Grabowski holds up a fish for Tanya to measure. David was Jon's lab tech at UNC.

In addition, one of the leaders from North Carolina (Jon Grabowski) has been down with us in Florida for the past week to help make sure that all three teams are doing the same thing.  While he was here, we also worked with a wonderful assistant up in Georgia (Caitlin Yeager) to figure out how to manufacture our experimental products.  The first part of this experimental puzzle involved figuring out how to remove baby oysters (spat) from oyster clumps in the field and to attach them to a standardized surface (tile).  Across all of our sites, we all want to start out with oysters of roughly the same size and age; otherwise, differences in our experiments among sites could simply be due to differences in starting oyster size or density, rather than to differences in predator diversity etc.   After we get all the spat attached to our tiles, we then built (well Tanya built most of them- thanks Tanya!) structures to put around our tiles, or not…

Tile Experiment

A partially open cage (cage control) that lets predators eat the oyster spat.

Our first structure was built to exclude all predators from munching on our oysters (i.e., predator cage).  Our second structure was a modified exclosure that mimics physical characteristics of the exclosure, but still allows predators to munch oysters (cage-control).  Finally, we have naked tiles that receive no structure or cage.  At 2 sites in NC, 2 in Georgia, and 3 in Florida), we will put each of these ‘treatments’ on all of the reefs (15 tiles/estuary or 105 tiles total).

But why do this crazy experiment thing?  Well, we will come back each month and monitor the traits of oysters and their survivorship.  With these results, we will compare survivorship or oyster traits from cages to that of the naked tile (“control”) to see if excluding predators improved oyster survivorship.  But because any improvement of oyster survivorship by the cage could simply be due to the physical structure (not to predator absence) providing shade during low tide or somehow changing flow (and food delivery), we will then compare cage results to that of the cage-control; now we can tell just how important predators are.

Another cool thing about the cages is that it may exclude predators from eating oysters, but they will not prevent predators from affecting traits of the oysters through intimidation.  So, do the traits of oysters surrounded by cages in Florida (maybe more oyster consumers) differ when compared to caged oysters in NC (maybe fewer oyster consumers).   Or, perhaps it’s that FL has more oyster food this time of year than NC and that better explains trait differences in oysters, not predators.  Or, maybe larger fish predators in Florida means less oyster consumers and less influence of oyster predation in Florida compared to NC, where there may be fewer large fish predators to eat the smaller crabs that love to munch on oysters.

To pull off this extra work, my Florida team will divide and conquer over the next week and a half.  Out of a team of four, 2 people will trap and gill net while the other two folks will set up the experiment.   This will involve ½ the team moving a head of the other team members at certain points.  But we’ll all overlap at each site for at least a few hours, which will then result in interesting stories about what each team has been observing.  Because we want to share this circus show with you over the next week, we’ll post updates every day.  We hope that this gives you a feel of what it’s like to get all of this done (both the good and the bad!).

Well, I need to go stockpile some sleep.

See ya,

David

David’s research is funded by the National Science Foundation.
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Searching for alternative explanations

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- biogeographic 150In many of our previous posts, we focused on how predator patterns may dictate why oyster reefs look different from NC to Florida. While a cursory look at results thus far supports this hypothesis, we’ve yet to consider alternate explanations. And failing to consider alternatives would not be very objective or scientific. After all, our job is to collect a lot of data and perform a lot of experiments that could possibly refute our predator hypothesis. Only by surviving all of these data and tests can our hypothesis gain strength, and of course it can never be proved. Continue reading