Tag Archives: biogeographic

The New Predator Experiment

Dr. David Kimbro FSU Coastal & Marine Lab

IGOR_chip_predators_NCE_100IGOR chip- biogeographic 150Hey folks,

Where did my winter of catching up on work go? And why is spring quickly hurtling into summer? YIKES!

…Okay, I feel better. All of us here feel a little behind on things, because this past winter and spring have been full of other projects (in addition to the oyster one) such as investigating how the oil spill affected marshes throughout the west coast of Florida and examining what all of those snails are up to out on Bay Mouth Bar. But now that summer is almost upon us, it’s time to move all hands on deck back towards the ambitious summer oyster goals.

Environment versus Predation

Environmental vs. Predator Effects.

To lay the ground work for this summer’s oyster research, I spent a few days in St. Augustine, Florida, which is where we will conduct our colossal field experiment. As a recap of the oyster objectives, we spent year 1 monitoring the oyster food web at 12 estuaries between Florida to North Carolina. Well, we found some cool patterns regarding the food web and water-filtration/ nutrient cycling services on oyster reefs (see the 2010 wrap-up). So, now we want to know what’s causing those patterns. Are differences in oyster reefs between NC to FL due purely to differences in water temperature, salinity, or food for oysters (phytoplankton)? Or, do we have a higher diversity of predators down south that are exerting more “top-down” pressure on the southern reefs? Or, is it a combination of the environment and predators? Continue reading

Reviewing the Oyster Study in 2010


IGOR chip_ predators_NCE 150IGOR chip- biogeographic 150IGOR chip- habitat 150IGOR chip- employment 150

Dr. David Kimbro FSU Coastal & Marine Lab
Summit_2

David's collaborators, from left to right- Dr. Jeb Byers, Dr. Mike Piehler, Dr. Jon Grabowski, and Dr. Randall Hughes.

As you can see from the video that summarized our efforts over 2010, it was a busy 6 months of research.  After taking a great break during the holidays, the entire oyster team (Jon = Gulf of Maine Research Institute, Mike = University of North Carolina at Chapel Hill, Jeb = University of Georgia, Randall = Florida State University and me) met for a long weekend to figure out what we accomplished and where we are going in the future.

You might think that our 2011 research plans should already be set given that we received funding.  Well, we did receive funding to carry out some outlandish field experiments in 2011, but these experiments were dreamed up in our offices and may not address the most ecologically relevant questions for our system.   Checking in with the monitoring data is probably the best way to determine if our planned experiments were on target or if they needed to be adjusted and hopefully simplified!

Prior to the oyster summit last weekend, I hounded all of the research teams for all of their data.  Given the huge volume of data and everyone’s busy schedules with teaching classes and other research projects, this was quite the task.  Once Tanya meshed all the data together (also not a simple task), I then moved on to the next task of analyzing our data.

Well, the initial excitement quickly turned into a stomach churning feeling of….where the heck do I begin?  Similar to the way that too many prey can reduce the effectiveness of predators, the data were swamping me…I was overwhelmed and the draining hourglass wasn’t helping (people were flying into town in two days…yikes!).

After multiple cups of coffee, the anxiety passed and I decided to revisit some basic questions:

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David's team used gill nets to catch the larger fish around the reefs, many of which are top predators in that habitat.

(1) With the gill nets, we obtained predatory fish data.  So how do the abundance and biomass of these fishes vary across latitude? And does this pattern change with season (i.e., summer versus fall)?

(2) Then I thought back to the fond memories of ripping up oyster habitat to check out the abundance of things that consume oysters (e.g., mud crabs).  Oh…the memory of that work gives me a warm and fuzzy feeling; I bet Tanya, Hanna, Linda and everyone else that helped feel the same way!  How do the abundances of these things change across latitude?  Are there larger crabs up north or down south?  How does the mud crab picture mesh with the predatory fish picture?

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This spat stick is made of calcium carbonate, the same substance as oyster shell, and is ridged to simulate the ridges in those shells. That makes it an attractive landing spot for oyster spat (larval oysters), which tend to settle on oyster shells.

(3) Working our way down the food web and sticking with the oyster samples we ripped up back in August, how do oyster densities and oyster size change across latitude and how do these patterns mesh with the mudcrab and predatory fish data?

(4) Finally, I wanted to revisit the data from our instrumentation to see how temperature and salinity changed across latitude and with season, as well as the data from our spat sticks to see how oyster recruitment differed.

It’s pretty amazing that six months of work can be summarized so quickly into four topics.  Well, I kept hitting the coffee and got all of these data worked up in time for the first portion of our oyster summit.  Surprisingly, all inbound flights arrived on time and we all assembled last Friday to go over the data.  I’ll briefly lift the research curtain to illustrate what our data looked like:

Jeb cuts blue crab from shark belly

The Georgia reef gill nets trapped a lot of sharks. Here Dr. Jeb Byers is removing blue crabs (also an oyster reef predator) from shark bellies. The trapping done on these reefs is clarifying the food web for these habitats.

(1) Although we predicted predator abundance to increase at lower latitudes, predator abundance and the number of different predators peaked in Georgia/South Carolina.  This is because lots of the species we have in Florida were also in Georgia.  And, Georgia has lots of sharks!  Needless to say, Jeb’s crew has been the busiest during gillnet sampling.  Jon and Mike’s crew have had it pretty easy (no offense)!  The workload reduced for everyone in the fall, but the differences across latitude stayed relatively the same.  The really cool result was the pattern that hardhead catfish are extremely important and the most abundant predatory fish on Florida reefs; I love those slimy things.

(2) Interestingly, mudcrab biomass peaked up north where predatory fishes were less abundant.

(3) And the abundance of large, market size oysters was highest where predatory fish were most abundant (GA/SC).

(4) Amazingly, we all did a good job selecting oyster reefs with equivalent salinities (this can vary a lot just within one estuary) and temperature was the same across all of our sites until December….instrumentation up north got covered in ice!  Glad I was assigned the relatively tropical reefs in Florida.  Finally, oyster recruitment in NC and Florida appears to proceed at a trickle while that of GA/SC is a flood-like situation during the summer.

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A month after first being deployed, Tanya and Hanna inspect an Alligator Harbor tile. You can see that some of the oysters have definitely started growing, but also that some of the spat became unglued. When they run the experiment again, they'll use a different adhesive more suitable for a marine environment.

After we all soaked that in, we then talked about the tile experiment.  While these data were really cool (mortality presumably due to mudcrabs was lowest where predatory fish were most abundant = GA), we worried about being able to tease apart the effects of flow, sedimentation, and predation.  Unfortunately, this experiment seems to uphold my record with experiments: they never work the first time.  We’ll probably repeat this in fall of 2011 with a much better design to account for flow and sedimentation.

Before breaking for a nice communal dinner at my place, Mike summarized the nutrient cycling (sediment) data that we have been collecting.  In short, having lots of living oysters really promotes de-nitrification processes and our sampling picked this up.

Putting this all together, it looks like there are latitudinal patterns in fish predators that may result in mudcrab density and size patterns.  Together, these may help account for latitudinal patterns in oysters (highest in GA).  This all matters because more oysters = more denitrification = healthier estuarine waters.

END DAY 1

On day 2 of the summit, we worked through what made us happy about the monitoring data, what things we could add on to make us happier, and that we should continue this monitoring through the summer of 2011.  This actually took all morning.

Summit_6

On day 2, the oyster summit moved into the more comfortable location of the Marine Lab guest house.

After a quick lunch break, we then reconvened in another room with a better view (nice to change up the scenery) to go over how we should experimentally test the linkages I mentioned above.  This is where the saw blade of productivity met a strong wood knot.  Personally, I became horribly confused, fatigued and was utterly useless.  This resulted in lots of disagreement on how to proceed and possibly a few ruffled feathers.  But nothing that some good food and NFL playoff football couldn’t cure.

After taking in a beautiful winter sunset over the waters off the lab, we ditched the work and began rehashing old and funny stories about each other.

Amazingly, we awoke the next morning and fashioned together a great experimental design that we will implement beginning June 2011.  To Jeb’s disappointment, this will not involve large sharks, but we will get to play with catfish!

But now it’s time to prepare for our winter fish and crab sampling.  It will be interesting to see what uses these reefs during the dark and cold of winter!

Thanks for following us during 2010, and please stick around for 2011 as I’m sure things will get really interesting as we prepare for our large field experiment.

Ciao,

David

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

Tanya Rogers FSU Coastal & Marine Lab


IGOR chip- biogeographic 150IGOR chip- habitat 150IGOR chip- employment 150(Editor’s Note.  Although David refers to Randall’s participation on this study, her role was not elaborated upon in this video.  That will be a part of the next video, on David’s collaborators, as Randall is David’s Co-PI- or Primary Investigator)

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Tanya measures a fish caught in a gill net.

It’s been said that research techs are those who do the dirty work in science. Although true in many ways, I love being where the action is, collecting the data, turning ideas into reality. That said, here is some of my perspective on what went into our October trip and what days in the field were like.

A busy field trip like our October sampling push typically takes at least as many days to prepare for as the length of the trip itself. Although the daily blog posts covered our time in action, David and I spent most of the previous couple weeks just planning for this trip so that it could run as smoothly as it did. I feel it worth mentioning the many hours I spent pouring over tide charts and editing and re-editing our complicated schedule so that we could accomplish everything as efficiently as possible, factoring in all manner of time and tidal constraints, travel time, land and sea transportation, overnight stays, and numerous other variables, plus designing it with enough flexibility that we could adjust our plans in the field at a moments notice (and indeed we did). In addition to scheduling I also had to make sure we had all the materials we needed to for our trip, that those materials were all in working order, and that they are all packaged up accordingly and conveniently in our two vehicles. The last thing you want is to be out in the field and realize you’re missing some critical piece of equipment.

striped burrfish

As they conduct these initial sampling trips every few months, they keep finding new and interesting species living in and around the reefs. Here, Tanya is taking measurement of one of her favorite finds of this last trip, a striped burrfish.

Out in the field, going to retrieve our traps and nets is always the most exciting for me, since you never know what we’re going to catch, and I was interested to see how the October fish community compared with that of July. We caught a few new fish species in our traps this round, including a beautiful spotfin butterflyfish (Chaetodon ocellatus), juvenile snapper (Lutjanus sp.), and a couple tiny pufferfish (technically striped burrfish, Chilomycterus schoepfi – they were very adorable). Equally exciting was getting to use the new motor on our skiff for the first time at our sites. Although noisy and bizarre-looking, it performed admirably in shallow water, as it was designed to. At least in terms of temperature and humidity, conditions on the reefs were considerably more pleasant for us than during the summer. It was wonderful not to be wiping sweat from your face every 10 minutes. The dramatic increase in the no-see-um population at dawn and dusk was not so pleasant however, as David has duly noted. The dawn low tide at Jacksonville brought the worst swarms we’d ever encountered in the field. Incredibly irritating both physically and mentally, they made work nearly impossible, and forced me to spend the subsequent week covered in uncountable numbers of ravenously itchy welts.

spotfin_butterflyfish

Despite its exotic look, the spotfin butterfly fish is a native of both the Gulf and Atlantic coasts of Florida.

When not out on the reefs, there was rarely a moment when something didn’t need to be done – whether filtering water samples, rinsing gear, or (most frequently) extracting spat. Our only breaks seemed to be for the necessities of eating, showering, sleeping, and making coffee. (For David, coffee appears to rank just below data and samples in terms of his most valued possessions in the field.) Our biggest and most time-consuming challenge was whether we could get all of the spat extracted and tiles made for our predator-exclusion experiment in the time allotted between netting and trapping. The process of isolating spat was incredibly tedious to say the least, and particularly frustrating when, after you’ve been working on a spat for several minutes, your tool slips and the spat gets crushed, or it flies across the patio, never to be seen again. You couldn’t help but feel the spat always picked the most inconvenient places to settle. It was also quite a messy process, with water and oyster bits flying everywhere and various crabs skittering across the counter. The oysters also love to slice your fingers open during the few moments when you neglect to wear gloves. Yet in spite of the tedium, we couldn’t help noticing new and interesting critters living amongst the oysters as we broke them apart. For instance, we noticed considerably more porcelain crabs (Petrolisthes sp.) and Boonea impressa (a small, white snail that parasitizes oysters) than we’d seen in previously collected oyster samples. We also found an oyster pea crab (Pinnotheres ostreum), which lives on and steals food from the gills of oysters, and a number of dark brown cylindrical mussels (Lithophaga bisulcata) that bore into the calcareous shells of oysters. It always amazes me how many different animals can be found living within the structurally complex habitat created by species like oysters.

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Young oyster spat, beginning their new careers in science.

I remember on one of the last days of our trip, I kayaked out to our St. Augustine reefs for a final service and check while David finished up the dremeling. I remember looking upon reef #5, seeing our newly deployed, spat-covered tiles and cages, our cleaned tidal data logger housing, and our newly replaced spat stick, arranged so neatly on our marked reef, and feeling delighted at our accomplishment, knowing how much effort has gone into this setup. I remembered that in my position it’s easy to get sucked into the details, but it’s equally important to remember the big picture, and how this research will contribute to our greater understanding of oyster reef ecology.

After our field trip, as we recover from battle wounds and wait for the mud to work its way out from under our fingernails, work on the oyster project continues at the lab. For me this has meant entering lots of data and starting to process our many samples. Before you know it though, it’s time to start to preparing for our next journey onto the reefs and the adventures that await.

The Kimbro, Hughes, et al. biogeographic oyster study is funded by the National Science Foundation.
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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.

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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.

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(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.

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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,

David

Day 7: October Oyster Push- Last Day

Rob Diaz de Villegas WFSU-TV

Thursday, October 28- Finish up, head back home

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(Farthest to nearest) Hanna, Tanya, and Cristina perform some of the more glamorous work of this trip- cracking oysters apart and finding spat (oyster babies). David needed everyone on his team to perform, or this week would be wasted.

IGOR chip- biogeographic 150A while back, I was talking to Randall or David, I forget which one, and they were telling me about building a research crew.  Obviously you need people who have the knowledge and skills to do what needs to be done- from identifying fish to driving a boat, or setting a gill net.  But just as important, they said, was that you had people you could get along with, since you practically live with them sometimes.

Weeks like this one are where building the team pays off.  When you’re getting bitten up by gnats on an oyster reef at 6:45 in the morning, you don’t want a crew member sniping at another about losing a fish out of the gill net.  David remarked to me that the morale of this team had stayed strong, despite the schedule always changing and everyone having to shoulder more of the load while David got the tiles ready.  They did a lot of work on their own, and made it possible to get everything done even as plans shifted.

On a day like today, it was good that David has the crew he has.

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A swarm of gnats hovers over the oyster reef water.

6:45 AM- Retrieved fish from nets, deployed traps.

After a night of battling cockroaches in their “haunted” house, they might have been happier to be out on oyster reefs at this early hour.  They might have, had it not been for the no see-ums.  They were getting eaten alive, which made it hard to work.  And it got worse from there, as if the universe decided to pile it on in this last day.

As early as it was, the birds had gotten to their fish before they did and there were no stomachs to examine.  And then there were the injuries.  David cut his finger on a catfish spine, and then, within about ten minutes, a stone crab got a hold of Hanna’s finger and inflicted some pain.  They’re both okay.  Their truck, however, is a little worse off.

Truck accident in Jacksonville

Banged up over the course of the week, the crew- and their truck- are ready to come home.

When they got back, they glued spat onto tiles one more time to deploy this afternoon.

3:00 PM- Tanya, Hanna, and Cristina retrieved the traps and set the tiles.

7:00 PM- The girls headed back to the FSU Coastal & Marine Lab.  When they got there, they cleaned all of their gear, even though it was late.  They figured that it was better to wash the salt off sooner than later.

So that was the week.  They’ll go back to each of the sites about every six weeks, though it won’t always be this intensive.  David, Jeb (SC/ GA), and Jon (NC) will start to see seasonal patterns in the fish that they find- when do certain fish tend to show up on what reef?  They’ll check in on their tiles and take photos, and over the months the photos should play like a flip book in showing the growth of the oysters on each site.  They’ll gain understanding, and they’ll run into more road blocks.  They have about two-and-a-half years left on this study, so while Thursday was the last day of the push, they’re nowhere near the end of the road.

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Assuming no one tampers with them, we should be able to watch these oysters grow up over the next year.

Check back in a couple of weeks for wrap-up posts from David and Tanya.

Tide Times and height (ft.) for Jacksonville, October 28, 2010
Low- 6:44 AM (0.3)

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

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