Tag Archives: mud crabs

Yes We Did!

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR chip- biogeographic 150The following is the first of three or so videos on the big October oyster trip.  In this one, you get a long busy day in the field condensed into two minutes (it’s much less exhausting that way).  We’ll have videos in the next couple of weeks on David’s co-collaborators (including video of the Georgia/ S. Carolina team and all the sharks they caught) and a video on David’s own team.


The "October Oyster Push" had many objectives, but none took as much time to implement than the tile experiment. Seeing how these baby oysters- spat- grow over the next few months will give David an idea how oysters typically fare at each reef over the course of their lives.

I spent most of this past week feeling pretty darn good about having just finished our October sampling and experimental objectives out on the oyster reefs.  Of course, this glow continued into the weekend as my football team pulled out a W in Tallahassee.

But back to the science.  Although Rob chronicled each day of our crazy road trip, I want to relive it once more just to give the trip from my perspective.  So, here are my top-ten thoughts:

Number 1: Planning the details of the road trip (housing, which team is going where and when) as well as figuring out how to set up the tile experiment (see video) was pretty stressful.  Thank goodness I had Tanya around to bounce scheduling ideas off of.  Because I kept chaning my mind, I think Tanya made like 6 different versions of our schedule.

Number 2: I talked the NC and SC/GA teams into doing the aforementioned experiment with oyster spat to examine how actual predation and the fear of being eaten affects oysters up and down the coast.  I successfully convinced the teams partly because I  emphatically claimed that the additional work load would only be five hours of more work at each site.  Well, I got that wrong.  It was probably triple that estimate.  That’s one of my flaws: I always underestimate how long research tasks take, which is bad because you constantly feel behind as a result of being over-scheduling.  Rule of thumb: always multiply my work estimates by at least 2.

Number 3: I never want to see a dremel again.  With dremel in hand one evening at Saint Augustine, I had only extracted ¼ the spat I needed for the experiment but the time spent on this task had already surpassed my previous estimate.  That’s when coffee and the ability to lose yourself in the task become extremely important.  I guess I took it one oyster spat at a time.


(L to R) Tanya, Hanna, and Cristina pick up the slack while David dremels away back at the lab space.

Number 4: I could not have lost myself in the task of setting up the experiment if it hadn’t been for Tanya, Hanna and Cristina.  Knowing that they were fully trained to carry out the sampling objectives, I did not have to busy myself with those numerous tasks, such as setting gill nets and traps (and retrieving the catch), taking sediment and water samples, etc.  In fact, after finishing the sampling objectives and follow-up lab work, they would immediately begin helping me with the experiment by cleaning adult oysters and identifying spat for me to extract with the dremel.  With that help, I was able to focus solely on dremeling.

Number 5: Dremeling 1080 spat out of adult oyster shell stinks.  Did I already say that? Well, this task deserves two spots on the top-ten list.  In tact, I probably attempted to extract over 2,000 oysters because I would often slip with the dremel and accidentally kill the oyster spat that I had spent five or so minutes on.

Catfish of Alligator Harbor

Hardhead and sail catfish seem to be the dominant predator of the Florida Gulf sites. By eating mud crabs that predate oysters, these fish perform an important function on oyster reefs.

Number 6: we couldn’t have asked for better weather.  In fact, I think there were some temperature records being set.  Despite these warmer than usual temperatures, there was about ½ the diversity and number of predatory fish on our reefs.  So, going against my expectations, these Florida sites are experiencing some seasonality in the assemblage of predators.  Interestingly, all teams were catching red drum on their reefs; guess it’s their time of year.  The red drum mostly had smaller fish in their stomachs.  The SC/GA team was still catching lots of sharks.  And catfish was still the most abundant predator on our reefs.  Those slimy things are definitely major players on southern oyster reefs because they had lost of mud crabs (who eat oysters) in their guts.  Final detail about the Florida sites is that my northern locations (Alligator Harbor on Gulf and Jacksonville area on Atlantic) had more predatory fishes than did the more southern sites in Florida…. intriguing.

Number 7: We had to change plans at the end of the week and this mid-course change actually went smoothly.  This change came about because the housing space near our Jacksonville site was not conducive for setting up the tile experiment.  Luckily, Hanna and Cristina ventured up to Jacksonville to figure all of this out for me.  This “divide and conquer” strategy allowed Tanya and me to finish up the sampling and experimental objectives in Saint Augustine, while Hanna and Cristina began sampling in Jacksonville to keep us on schedule.  And rather than resting up in Jacksonville, Hanna and Cristina ripped up oyster habitat and drove it back down to Saint Augustine.  They looked pretty rough upon that later return to Jacksonville.  But after a good dinner and a few hours of sleep, their oyster delivery allowed us to work on the materials for the Jacksonville experiment in a much better laboratory setting.

Number 8: Team morale and will to finish objectives hit a low point once we reached Jacksonville.  The lodging for the first evening was haunted with cockroaches: this is Hanna’s kryptonite.  Luckily, Tanya whipped us up some good pasta to help keep our minds off of the roaches.  The next morning, cockroaches began to seem not so bad.  When we got to the boat-launch and found there to be no wind, I knew it was trouble because this site had the reputation for being particularly buggy.  So, we headed into the mouth of our creek and hit the first reef.  Not too bad… actually, no fish in the nets.  Only a few bugs and two free hands to swipe them away.  But as we ventured further into the belly of the creek/bug hell and found tons of fish in our nets, I began to worry about mutiny.  As I was exhorting the crew to extract tons of fish from the next set of nets, I realized that freeing this many fish would take twice as long because we needed to spend an equal amount of time cursing the no-see’ums and keep them out of our ears and noses; kind of hard to do with fish in your hands.  While taking fire from the no-see’ums, we then began sustaining additional injuries from other natural agents.  I suffered my first good-sized oyster cut.  Hanna got her finger nearly cut off by a large stone crab.  For the pain finale, a decent sized catfish stabbed my hand with the barb of its dorsal fin.  I don’t blame it, but daggum that hurt.  At this point, the unpleasantness was almost comical.  Note to self: buy hats with bug nets to combat no-see’ums.

Number 9: All of the pain and stress of that week is now good fodder for the lab to laugh about and bond over.  That’s one of the perks of conducting research as a team.  And that’s one of the reasons why Big Jon, Randall and I are still collaborating.


David walks away from the tiles he and his team spent so much time putting together. He won't know how successful the experiment was until he travels back to these sites.

Number 10: Now that we have all caught up on sleep, have relived our stories, and have begun to look at the data, I now stress about whether the tile experiment will actually work.  Like most experiments I conduct, I put a lot of effort into something that has a 50% chance of not succeeding.  For example, the spat that I extracted and adhered to tiles may have been overheated by the dremel/extraction process…are they dead already?  And then, oh boy…what if the glue doesn’t hold?  That’s what really keeps me up at night.

Till next time,


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.
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This is what an oyster reef looks like…

Rob Diaz de Villegas WFSU-TV


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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A closer look into the reefs

IGOR chip- habitat 150The following photos are of samples taken at each of Dr. Kimbro’s sites, as mentioned in his previous post.  After surveying the reefs to see what large fish and crabs were living in the reefs, he and his team turned to looking at the oysters and the creatures living under them in the mud.  That’s what you’re seeing here.  Click on any photo to make it larger.

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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.


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.


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.



David’s research is funded by the National Science Foundation.
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You can’t enjoy watching the game if you don’t know who the players are

Dr. David Kimbro FSU Coastal & Marine Lab

See David and his crew in action, and see what animals are on Alligator Harbor reefs.

IGOR chip- habitat 150The title of this blog (a sports metaphor) is how my teacher first introduced me to marine ecology. For our oyster project, this essentially means that we need to establish who is on the oyster reefs before we can begin to make connections among predators, oysters, and their water filtration services….as well as (unfortunately) the impacts of oil.

So far, we’ve identified the organisms on the bottom rung of our food web (think of it has a pyramid): oysters, clams, amphipods, and polychaetes on the bottom rung of the food web and mud crabs and snapping shrimp on the next higher rung of the food web. Our goal this week was to begin quantifying who is at the top of this food pyramid. To do this, we deployed crab traps, bait-fish pots, and gill nets onto each of our reefs during low tide. Following the ensuing flood tide, we returned the next day to count our catch and then promptly release everyone.

hardheaded catfish

the hardhead catfish was the most abundant species trapped during this survey

Although we caught a couple of interesting things (e.g., adult stone crabs, mullet, spot, as well as juvenile pinfish, pigfish and silver perch), I was surprised by the low abundance and diversity of our catch and that the most abundant species was catfish!

But after running out of fresh water to drink and profusely perspiring all the moisture out of my body while out on the reefs, it dawned on me that nature of this catch is likely an interesting seasonal pattern (again, I’m new here!): only hardy organisms that can tolerate really hot and low oxygen waters are going to be on Florida reefs right now. Once the rest of this research team begins collecting similar data from Virginia to Florida, it will be interesting to see if these low abundance-diversity patterns might last longer in some areas (e.g., Florida with longer summer) than in others (e.g., NC with shorter summer). If that’s the case, then the cascading effects of higher order predators (things at the top of our food web) down to oysters and their water filtration services may be occur more consistently during the summer in northern than in southern estuaries.

Hmmm…..good thing we are conducting a relatively long-term study and will consistently repeat this sampling in the future to rigorously detect interesting patterns like this one.

Until next time…

The Music in the video was by Jim Crozier.  As always, we welcome submissions from local musicians. WFSU’s kayak was provided by Wilderness Way.

David’s research is funded by the National Science Foundation.

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The unsung heroes of the muck

Roberto Diaz de Villegas WFSU-TV

photo by John Spohrer

Let’s talk about the little guys.

Think a little smaller than this pelican here.  Obviously, pelicans are a symbol of our coastal areas, flying in those long rows as they do while we’re driving down Highway 98.  Pelicans covered in oil have become the poster-species of the environmental toll of the Deepwater Horizon oil spill.  It’s horrifying to think of animals as evolved as dolphins washing up on the shores, and people of course are always concerned about sea turtles.  As they should be.  They are all important parts of the Gulf ecosystem.

But they are not the only important parts.  There are other creatures that probably won’t make it on to that oil spill tragedy poster because, let’s face it, they already live in muck.  Those are the species that we’ve been most concerned with on this site.  They are worth worrying about, and I’ve come to find them cute in their way.  I keep thinking I need to try to get Disney to make a movie based in a salt marsh or oyster reef, where mud crabs and periwinkle snails sing and hide from predatory blue crabs (who, like those sharks in Finding Nemo, might be sympathetic characters themselves).  When kids are carrying plush fiddler crab dolls, maybe the little guys would get some consideration.  As it turns out, however, I have no pull at Disney.  So I’ll just talk about them right here on this blog.

Like the fiddlers.  They eat sand.  They shovel it in their mouths with their smaller claws, while they do the mating dance for which they’re better known with their larger “fiddle” claws.  I see thousands of them at a time in a salt marsh, always scurrying away and making that sound, a little bit like trickling water and a little bit like tiny bubble wrap being popped.  Of what importance are these silly little guys?

Fiddler on marsh 2

Fiddler crabs are crucial to the survival of a salt marsh

Other than being food for blue crabs, their importance has to do with the muck in which they live.  They live in the sediment collected by the cordgrass root system; you can see the holes they call home throughout the marsh.  As Dr. Hughes explained in this video, these burrows provide oxygen to the soil in which the cordgrass grows.  So their presence helps the cordgrass grow, just as the cordgrass provides them shelter.

So maybe the fiddler crab hasn’t found himself at the center of any teary oil spill montage.  But he’s an animal, and a fairly popular pet.  Spartina alterniflora- aka smooth cordgrass- may never gain a foothold in the popular imagination proportionate to its ecological importance.  It is the foundation species of a Gulf salt marsh.  These marshes act as a filter for pollutants flowing into the ocean, protecting important estuaries such as those at the mouth of the Apalachicola River.  Marshes provide shelter to a number of commercially important species (shrimp, mullet, and blue crab, for instance).  And marshes also help absorb storm surges and prevent erosion.

Those are just a couple of examples.  There are, of course, more.  Tasty, tasty oysters filter water and prevent algal blooms lethal to other species.  Toadfish have faces even other toadfish may not love, but they eat animals that would decimate oyster reefs if left unchecked.  Those oyster predators are interesting as well.  Mud crabs might get as large as 4 cm and have these thick little claws which tear through oyster shells.  Oyster drills are small snails whose tongues (radula) are covered with thousands of small razor-like teeth.

As we move forward with this project, we’ll see more and more of all of these coastal denizens.  So far oil has not reached the areas Dr. Hughes and Dr. Kimbro are studying, and so there is always hope that they may be spared.  If oil does arrive, many of these species could be severely affected.  And while some of them may not look like much, the harm that would come to them would have repercussions felt beyond their own habitats.


This snail lives on an oyster reef

Interested in seeing a fiddler crab plush toy as a WFSU-TV pledge premium?  Well, that isn’t likely to happen. But we will take comments and questions, as usual.

What we are doing on the reefs

Dr. David Kimbro FSU Coastal & Marine Lab

Oyster reef

Why are we on oyster reefs?

IGOR chip_ predators_NCE 150Well, I am broadly interested (and hope to make you interested) in how large predators can help protect important habitats like oyster reefs by preventing smaller animals from eating all the oysters.  I’m sure you can agree that we don’t need anything competing with people to eat oysters! It’s also important to keep enough oysters on the reef to filter water and provide habitat for lots of fishes and invertebrates, because these processes help keep estuaries healthy, and healthy estuaries support critical economic and recreational activities along our coastline.

Because 90% of the oyster reefs in the world were either eaten (they taste really good) or dredged away (they are a pain for boats to get around), we are specifically studying whether predator-prey interactions determine how the remaining 10% of our oyster reefs operate.  For example, it turns out that large predators such as fish and big crabs can protect oysters either by eating the smaller snails and crabs that consume the oysters or by scaring the snails and crabs enough to spoil their appetites for oysters.

Why should it matter whether the large predators eat or frighten the smaller predators, as long as the oysters don’t get eaten?  Since oysters are sessile, they can’t run away from their predators, but they can stop filtering water when predators are around in order to avoid producing a signal that can give away their location.  So if there are lots of oyster predators around, even if they are scared and not actually eating oysters, they may still keep oysters from filtering water.  And, the amount of water oysters filter matters, because filtration can remove excess nutrients from the water, helping to prevent algal blooms and low oxygen conditions in coastal waters (bad for fish and other animals).  This potential link between predators and nutrient cycling and whether it operates the same way in different places is why myself and researchers from the University of Georgia, University of North Carolina at Chapel Hill, and the Gulf of Maine Research Institute are out studying reefs from Florida to Virginia.

gulf oyster reef food web

If we can understand why more oysters survive in certain locations and how these oysters affect nutrient cycling differently in different locations, then we can better target our restoration dollars when trying to recover the other 90% of our oyster reefs, thereby getting the biggest bang for our buck.

We’re just getting started.  And as you can see from the photos and videos, it’s a slow and ungraceful process at first!

David’s research is funded by the National Science Foundation.

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