Tag Archives: oyster

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)
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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.
We want to hear from you! Add your question or comment.

Days 1 & 2: October Oyster Push- “Just Gun it”

Rob Diaz de Villegas WFSU-TV
Alligator Harbor at sunrise

The sun is about to rise in Alligator Harbor.

IGOR chip- biogeographic 150The first leg of David Kimbro’s Roctober oyster push is now complete.  If you look at the schedule below, you’ll see the first day was intensive, starting in the wee hours and going late into the night.  As David mentioned in his post, the head of the NC team (Jon Grabowski) was along for the fun.  David was Jon’s lab tech once upon a time, as was Dr. Randall Hughes (In the Grass).  So tagging along I definitely got some “family reunion” vibes, with lots of good natured ribbing (let’s just say it was good-natured).

For this October push, David will be breaking in a new boat to help his team cover ground more efficiently while lugging traps and samples around.  In order for the boat to move in shallow water, David replaced the motor with a lawnmower engine.  It worked fine on Thursday, when the water was higher, but it had a few problems Friday morning at low tide:

Jon drags the boat- and Tanya and Alicia

Jon Grabowski drags the boat- along with and Tanya and Alicia- after not being able to drive the boat through shallow waters.

Finally, they were able to get it to go.  The solution?  As David’s tech, Hanna, said- “Just Gun it!”

The catch this time was a little different than the last, with new fish like Red Drum ending up in the gill nets and no juvenile fish being caught in the minnow traps.  They also started looking into the stomachs of some of the predators (they have a permit to do so if the fish die in the net) and are seeing that the catfish here are eating mud crabs.  Mud crabs, of course, are key oyster predators.

Hanna kayaks

Early Friday morning, Hanna Garland kayaks to "site 1" in Alligator Harbor.

We’ll be heading out with David’s crew throughout the week.  On top of all of the other arrangements they have to make to move their crews around multiple sites hundreds of miles apart, they have to accommodate our camera crew.  So thanks for finding a way to drag us along!  Hopefully we can show people the kind of work that goes into making this kind of research happen.  There’s a lot of work to go along with the science, and with every subsequent sweep and new experiment, the patterns will hopefully clarify and our understanding of these ecosystems- and how to best conserve them- will be that much further advanced.

David’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.

Thursday, October 21-  Alligator Harbor

8:30 AM- Retrieve tiles, sediment, and spat. (TI)

11:07 AM- Deploy traps (N/T)

5:07 PM- Retrieve traps.  High tide activities: reference water level, water samples, replace spat sticks.  Unlike in the previous sampling done in Alligator Harbor, there were no juvenile pinfish or pigfish.(N/T)

8:00 PM- Deploy nets.  The nets will be retrieved Friday morning to give David an idea about what was swimming around over night.  (N/T)

Tide Times and height (ft.) for Alligator Harbor, October 21, 2010
Low-  8:07 AM (0.2)
High- 2:12 PM (2.7)
Low- 8:07 PM (0.9)

P1010300Friday, October 22-  Alligator Harbor

8:00 AM- Retrieve nets, data logger.  Today there were a lot of red drum (redfish) and of course, catfish (hardhead and sail).  On site dissection reveals that the catfish eat mud crabs, thus serving the same role that toadfish serve in North Carolina reefs. (N/T)

8:30 AM- Return tiles/ oysters.  The tiles for the new spat experiment mentioned by David go out today. (TI)

Tide Times and height (ft.) for Alligator Harbor, October 21, 2010
Low-  8:40 AM (0.1)

David and his team are taking Saturday off.  Bright and early Sunday morning, the Net/ Trap team heads for Cedar Key while the Tile team heads to Saint Augustine.

David’s research is funded by the National Science Foundation.
We’d love to hear from you!  Leave your comments and questions below:

Why do we eat Apalachicola oysters instead of those from Alligator Harbor?

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- gastronomy 150IGOR chip- biogeographic 150In my previous post, I described how tides could influence the oyster patterns that we are observing throughout the Atlantic and Gulf coast.  But throughout the Gulf coast, can tides explain why most of the oysters sold in restaurants come from subtidal reefs?  Are subtidal oysters healthier, happier and thus more abundant?

Well, before I attempt to address this issue, let’s first talk about the difference between subtidal and intertidal oyster reefs.  The term intertidal refers to a habitat that spends part of the day submerged by water and the other part of the day out of the water.  In contrast, the term subtidal refers to habitats that are constantly submerged by water.  Interestingly, along the NW coast of Florida, oyster reefs are subtidal from Pensacola to Apalachicola Bay.  And east of Apalachicola, oyster reefs become intertidal.

P1000082

Fouling organisms grow on hard surfaces under water.

Now back to the second question above: are subtidal oysters happier and healthier than intertidal oysters?  Research by Dr. Charles Peterson at the University of North Carolina at Chapel Hill suggests the answer is no because both reef types have different costs and benefits that keep growth and health roughly the same.  For example, subtidal reefs may get the benefits of being inundated all the time by food-rich water, but this constant submergence also has costs that include: getting covered by fouling invertebrates (i.e., animals commonly found on the bottom of boats that look like silly puddy) that compete with oyster for food and being exposed to more marine parasites and disease.  In contrast, the harsh sun baking that intertidal oysters receive during every low tide can be painful and they may also get exposed to less food, but the sun baking also cooks off the silly-puddy competitors and it also keeps the parasites away.  In the end, these different costs keep growth rates about the same between subtidal and intertidal oyster reefs.  This is why intertidal oysters from Cedar Key, Florida can be just as big and delicious as subtidal oysters from Apalachicola.

Now I’m ready to tackle the first question  from above: why do so many more oysters come from subtidal reefs in Apalachicola than from the intertidal reefs to the east and why aren’t intertidal oysters always equally as large and tasty as subtidal oysters?  After talking with an extremely knowledgeable biologist who has been studying and working with Gulf coast oysters for nearly thirty years (John Gunter), I can fairly confidently say that the answer deals with the size of the fresh water input entering an estuary and diversity.  This is because good oyster production requires a tricky balance between fresh and salty water that keeps marine predators/disease at bay and fuels phytoplankton for growth and reproduction.  So, a larger source of fresh water input creates a larger portion of an estuary suitable for oysters to achieve this delicate balance.  But the amount and timing of fresh water input, along with the weather, varies from year to year.  As a result, one set of fresh-water input and weather conditions may be good for one portion of the estuary and not so good for the other portion of the estuary.  But the next year, this situation could become reversed, maintaining a constant level of production through varying levels of fresh water input and climate.  In other words, Apalachicola has a relatively large and diverse oyster portfolio.

P1000796

Without a steady influx of freshwater, intertidal reefs have no assurance of being consistently healthy and abundant.

In contrast to the subtidal oyster reefs in Apalachicola, the size of fresh water sources that influence intertidal oyster reefs to the east are significantly smaller.  Consequently, there are only a few spots where oysters can thrive.  When conditions are just right, these intertidal reefs produce oysters just as tasty and large as the subtidal ones form Apalachicola.   But when conditions are sub-par, those intertidal oyster reefs shut down and there are no other reefs to make up for this loss in production; these estuaries have small and non-diverse oyster portfolios.

Ok, now that I waved my arms about the difference between subtidal and intertidal oyster reefs and why restaurants mostly serve subtidal oysters, I need to go get ready for our next big outing onto the oyster reefs, which should be extremely busy, but fun.

Talk soon,
David

David’s research is funded by the National Science Foundation.
We want to hear from you! Add your question or comment below.

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

This is what an oyster reef looks like…

Rob Diaz de Villegas WFSU-TV

IMG_3499

The photo above is my work computer’s desktop picture. Most of the time, when people see it, I find that they had no idea what an oyster reef looked like.  One coworker thought it was a muddy cabbage patch.  To be honest, until I first stepped on one for this project, I wouldn’t have known a reef from a pile of rocks.  And, like a lot of people, I love eating the things- right out of the shell with a little grit and juice.  That’s the disconnect we sometimes have between the food we eat and from where it comes.  So it occurred to me that, while we’ve been talking these last few months about the complex relationships between predators and prey on the reef, it might be helpful to get back to oyster basics.  Over the following weeks, we’ll cover various topics (like why subtidal oysters are harvested more often than intertidal ones like those up there).  We’ll start with what it’s actually like out on a reef, and what you’d see there.

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On the Road Again

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- biogeographic 150As my assistant Tanya eloquently wrote in our last post, our July efforts produced interesting data on the predatory fish and crabs that hang around oyster reefs from North Carolina to Florida.

CK_exposed_reef

Cedar Key reefs, like the one above, tended to be sparser with slightly larger oysters than those in Alligator Harbor

After working on our sleep deficits, we dialed up some Willie Nelson on the iPod and were on the road again during the second week of August.  Our goal: to determine if predator patterns on oyster reefs from NC to Florida were associated with any patterns in oysters (e.g., number and size) and smaller animals that both use oyster reefs as habitat (e.g., polychaetes and crabs) and as food (e.g., crabs).

This destructive sampling involved ripping up large sections of our reefs and placing them in large bins while trying to prevent any crabs or other critters from falling out.  Because these are marine organisms, we had to work fast and quickly get them into a temperature-controlled room (50 degrees F) back at FSU’s Marine Lab.  Easy when collecting samples from nearby Alligator Harbor, but not so easy when collecting samples at our other three sites in Florida.

KImbro Team oyster reef sitesBut before dashing back to the lab, we deployed some instrumentation and took lots of sediment and water samples (more about this stuff later).  Then, the race to keep our samples fresh commenced and mostly occurred on I-95 and I-10; I’m still seeing lane dividers and road reflectors when I close my eyes at night.  After a few hours of sleep, we would drive back across the state to another site and start the process all over again.  All of this sleep deprivation and highway racing against biological clocks made me feel like I was Smokey the Bandit boot-legging some Coors Beer across state lines (maybe I’m showing my age here, but a classic movie nonetheless).

Luckily, we had some great volunteers to help process these samples back at the lab while I was out ripping up oyster reefs, because processing each sample took a long, long time.

processing

Liz and Hanna sort the reef samples.

After a week and a half of sample processing, it was really cool (or so I hear, because I was mainly on the road) to see all the animals living within the oyster reefs and how they and the reefs themselves differed from site to site.  For instance, Alligator Harbor seemed to have dense reefs of small oysters while Cedar Key had sparse reefs with slightly larger oysters; both had few mud crabs (maybe due to the abundance of big fish?).  We also noticed that animals north of Jacksonville must be on growth hormone supplements because everything is gigantic (bigger mussels, bigger crabs, and bigger oysters).  Meanwhile, the crown conch population in St. Augustine is huge and appears to be mowing down the oysters.  So, now I have new side-project: why are crown conchs an abundant nuisance for oyster reefs in St. Augustine but not at other sites?

From one week of field work, we now have about a month or so of associated lab work that will involve counting, measuring, and identifying every organism.  I’m really excited to see how all the predator, intermediate consumer, and oyster reef data correlate from estuary to estuary.

Best,

David

David’s research is funded by the National Science Foundation.
We want to hear from you! Add your question or comment.

Two Poems

IGOR chip- human appreciation 150 Here are two more poems by Dawn Evans Radford.  In her first post, she depicted the day of an oysterman. Here we have a limerick about the oysters themselves, and a more serious piece on our relationship with our natural surroundings.

Dawn Evans Radford

Limerick

Down in the bay lived a plump little oyster
whose hormone changes eventually forced her
to fly into a tizzy.
Cried she, I get dizzy
trying to decide if I’m a girl or a boyster.

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Oysterman

IGOR chip- human appreciation 150IGOR chip- employment 150

In Yesterday’s post, Tanya Rogers wrote about an old-timer oysterman in Jacksonville whose local knowledge aided David Kimbro and his team in locating reefs to study.  In today’s post, we take a poetic look at the life of an oysterman.
This is the first post by Dawn Evans Radford, a resident of Franklin County with deep roots in the area.  She is a published writer of poetry, literary research, and fiction; her novel Oyster Flats won the 1993 Sherwood Anderson Award.  Most recently she contributed to Unspoiled, a compilation in which Florida writers speak for the preservation of Florida’s wild coast and against offshore drilling.  She is currently writing a second novel and, happily, contributing posts to this site.
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Counting the Catch

Tanya Rogers FSU Coastal & Marine Lab
Tanya Rogers

Tanya Rogers

IGOR chip- biogeographic 150IGOR chip- habitat 150As Dr. David Kimbro’s research assistant, I help out with all aspects of the biogeographic oyster project in the field and at the lab. David, myself, and Evan Pettis (an intern from FSU) have returned from our big sampling effort to characterize the predator community on the oyster reefs at our chosen field sites. Over the course of a productive yet exhausting week, we successfully deployed and retrieved nets and traps at Alligator Harbor, Cedar Key, and St. Augustine and found very interesting differences in the abundance and diversity of fish species between sites. St. Augustine had by far the greatest diversity of large fish species, including redfish, snapper, toadfish, flounder, jack, ladyfish, bluefish, and menhaden. At Cedar Key and Alligator Harbor we caught longnose gar, a fascinating and very ancient fish with extremely hard scales and a long toothy snout. The largest fish we encountered were black drum, which we only captured at Cedar Key. Pinfish, hardhead catfish, and striped mullet were present at all of our sites, although in varying abundances.

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