Rob Diaz de Villegas WFSU-TV

Much like Slave Canal connects the Aucilla and Wacissa Rivers, this post serves as a bridge between our oyster reef and salt marsh videos (not that we’re done talking about Apalachicola by a long shot).  One of my favorite things on this blog is when we can make connections between rivers and the coast.  Of course, rivers provide much needed nutrients and fresh water to the estuarine ecosystems I just mentioned.  But to the many cultures that predate european settlement of our area, they served as the equivalent of Woodville or Crawfordville Highway.  It’s how they got to their Forgotten Coast seafood.

An old growth Cypress tree fortunate not to have been logged. Judging from the size of its base, Joe Davis estimates that it could be as much as 1,000 years old.

Slave Canal is one of those places I started hearing about a lot when we started doing our EcoAdventure videos.  As soon as you get into the braided channels of the lower Wacissa, it’s easy to see why it’s one of the popular river expeditions in north Florida.  You’re paddling in a canopied river swamp where people have been paddling for several thousand years.  And minus some old growth cypress trees that have been logged in the last century or so, it looks much the same as it did when various native groups made use of the waterway to make seafood runs to the coast.  But it doesn’t look quite as it did when people first got there.

Evidence excavated at the Page/ Ladson and Ryan/ Harley sites points to people inhabiting what is now the Aucilla Wildlife Management Area for 12,000 years or longer.  At that time, Florida Fish and Wildlife’s Joe Davis told us, the ice ages were ending, sea level was lower, and the coast was further away.  Those first men and women walked on dry land where our canoes and kayaks passed over.  I can almost envision paleolithic man standing on one of the many ancient midden mounds as everything happens around him in time-lapse mode.  Rivers fill and flow to the Gulf, mastodons vanish, and different cultures come and go, piling shell and bone on to that same mound.  Pretty heavy stuff to think about on a fun Florida kayaking trip.

So how do you get there? Florida Department of Environmental Protection put this PDF together with driving directions to two put in points along the Wacissa Paddling Trail. One is for the headwaters of the Wacissa, though Goose Pasture is closer by ten miles. It depends on how long you want to kayak or canoe. It’s about five miles from Goose Pasture to Nutall Rise on the Aucilla.  Goose Pasture is also a camp ground (first come first served, call 800-226-1066 in Florida or 386-362-1001 for more information).  Scroll down in the PDF for advice in finding the entrance to Slave Canal (hint- stay to the right). If you don’t find it amongst the braided channels of the lower Wacissa, you won’t find your take out at Nutall Rise.

Slave Canal is our third EcoAdventure on the Aucilla Wildlife Management Area.  We paddled the upper Wacissa and got some underwater footage of Big Blue Spring.  We also hiked the Florida National Scenic Trail along the Aucilla Sinks, where the Aucilla River goes intermittently underground, peeking out in “Karst windows.”  The WMA is a marvelous synthesis of history and prehistory, wildlife, and geology.  And, well, it’s full of these cool looking places.

This is Nigel Foster, of Nigelkayaks. This link is to the trip gallery on his website.  As you can see, he’s been a few places.

And this is Russell Farrow, Liz’s other guest. Russell is a co-owner of Sweetwater Kayaks in St. Petersburg, and you can see he’s been a few places as well. One of his passions is getting kids into the outdoors (and away from their screens).

I do one thing on this blog all year that takes place away from the coast, but I can’t escape oyster shells. For how many thousands of years have people eaten oysters on the Forgotten Coast? This shell was on Coon Bottom Mound, the largest mound on Slave Canal.

I’m looking forward to the next EcoAdventure, whatever that might be.  If you have any suggestions, leave a comment.

In January, David Kimbro’s lab did a preliminary survey of Apalachicola Bay oyster reefs, looking at the overall health of oysters and the presence of predators. They followed this up with an experiment meant to monitor oyster health and predator effects over time. Many of their experimental cages were displaced, likely due to the buoys marking them breaking off. But what they found in the cages that remained intact was that oyster drill numbers appear to be exploding in warmer waters.  David is looking for help keeping tabs on them.

Dr. David Kimbro Northeastern University/ FSU Coastal & Marine Lab

Wishing that you were wrong is not something that comes naturally to anyone. But that is how I felt at the most recent oyster task force meeting in April. There, I shared some early research results about the condition of the oyster reefs. In our surveys, we found that the oyster reefs in Apalachicola Bay were in really bad shape and that there were not any big bad predators hanging around the reefs to blame. Even though I had originally shot off my big mouth about the oyster fishery problem being caused by an oyster-eating snail, I hoped that our first bit of data meant the snails were never there. Or better…that they were gone. The story of the boy who cried wolf comes to mind.

But an alternative of this David-cries-wolf story is that our January sampling didn’t turn up many predators because it’s cold in January, and because they were hunkered down for a long winters nap. Unfortunately, this option is looking stronger.

Experimental cages to be deployed in Apalachicola Bay.

Since the task force meeting, we have been figuring out how conduct field experiments in Apalachicola. To be honest, an underwater environment without any visibility is an experimentalist’s worst nightmare. Still, we deployed fancy equipment, big cages, and then little mini experiments inside each big cage to figure out how much of the oyster problem is due to the environment, to disease, or to predators.

Even though we lost over half of our experiment and instrumentation, we recovered just enough data to show that the problem could be predation and that the culprit is a voracious snail.  So, after learning some lessons on how to not lose your equipment, we decided to take another crack at it. In fact, Hanna and crew just finished sampling half of our second experiment today. We got the same results….lots of snails quickly gobbled up all of the oysters that were deployed without protective cages. But the oysters that were protected with cages did just fine.

This photo illustrates what Apalachicola oyster reefs are dealing with. This is one clutch of eggs laid by one adult snail. Within each little capsule, there are probably 10-20 baby snails. After a long winter’s nap, these snails are hungry.

We are going to keep at this, because one week long experiment doesn’t really tell us that much. But if we keep getting the same answer from multiple experiments, then we are getting somewhere.

In addition to updating y’all, I wanted to ask for your help. Because my small lab can’t be everywhere throughout the bay at all times, there are two things you could do if you are on the water.

Click the link to the right for GPS coordinates.

First, if you come upon our experiment, can you let me know when you happened upon them and how many buoys you saw? If you report that all buoys are present, then I’ll sleep really well. And if you alert us that some buoys are missing, then I’ll be grateful because we will stand a better of chance of quickly getting out there before the cages are inadvertently knocked around, so that we can recover the data.  Click here for GPS coordinates and further instructions.

Second, if you are tonging oysters, then you are probably tonging up snails. It would really help us to know when, where, and how many snails you caught.  Take a photo on your phone (Instagram hashtag #apalachcatch – Instagram instructions here) or e-mail them to robdv@wfsu.org.  We’ll be posting the photos and the information you provide on this blog.

This is kind of a new thing for us, attempting to use technology and community support this way.  There may be some bumps along the way.  If you’re having trouble trying to get photos to us, contact us at robdv@wfsu.org.

Thanks a bunch!

David

David’s Apalachicola Research is funded by Florida Sea Grant

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

Rob Diaz de Villegas WFSU-TV

CBA staff from L to R: Brandy Foley, Jeff Murphy, and Rachel Gwin listen as Allison McDowell explains how the reef is to be laid out. She had previously laid the section visible under the water.

I’ve been wanting to do a video on Choctawhatchee Basin Alliance‘s Oyster Recycling program for some time.  I decided to do it now because we’ve been covering restoration efforts in Apalachicola Bay, and while the two efforts appear to have similar goals, they’re both using different methods and aiming at different goals.  In Apalachicola, they’re trying to restore their fishery.  They want oyster spat to settle on their shells and grow into market sized (3 inches or more) adults.  In Choctawhatchee, they’re rebuilding their coastline.  It’s an ecosystem service we have mentioned in the past but have struggled to show, how oyster reefs (and salt marshes) prevent erosion.  You can see in the video above how the coastline is retreating and exposing tree roots where these natural barriers have been removed.  And you can see how the sand just accumulates where they’ve replaced shell.  It’s one of the many beautiful things an oyster reef does.

With 85% of the world’s oyster reefs having already been lost, and with more being threatened, restoration is critical.  Many of those efforts center around what’s left in your basket when you leave the raw bar.  Every part of the oyster is valuable.  The animal itself cleans the water and provides income for oyster harvesters.  But it’s also a builder, and an oyster reef provides shelter for various fish, crab, and snail species, many of which we eat.    The shells that make the reef are the best place for a larval oyster to land.  So those dozen or two shells you walk away from have their value as well.  Thankfully, people like the Choctawhatchee Basin Alliance staff and volunteers are doing the hard work of collecting them and putting them back to work for the reef.

This is a refrigerator at Busters in Santa Rosa Beach. Standing behind the bar, Donnie Sellers shucked 75 dozen oysters the day we were there, and that was before tourist season. All of the restaurant's shells end up in blue recycle bins.

Music in the Piece by Red Lion.

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

Last week, Hanna Garland showed us how the Hughes/ Kimbro Lab adapted their techniques for underwater research in Apalachicola Bay. She talked about their difficulties with the weather, and as you can see in the video above, it was difficult for their oysterman collaborator (as it is for Apalachicola oystermen these days) to find enough healthy adult oysters to run the experiment. Below, David Kimbro looks back at the big Biogeographic Oyster study and what it has taught them about how oyster reefs work, and how they’ve been able to take that knowledge and apply it to the oyster fishery crisis.

Dr. David Kimbro Northeastern University/ FSU Coastal & Marine Lab

Does our study of fear matter for problems like the Apalachicola Bay oyster fishery crash? Absolutely.

Bear with me for a few sentences…

I like to cook. My first real attempt was a chicken piccata and it was a disaster. After ripping off the recipe from my brother (good cook), I quickly realized that the complexity of the recipe was beyond me. To save time and fuss, I rationalized that the ordering of ingredients etc. didn’t matter because it was all going into the same dish. Well, my chicken piccata stunk and I definitely didn’t impress my dinner date.

2010: David paddles to a St. Augustine oyster reef during his lab's first tile experiment. Since then they've done two spat tile experiments and two cage experiments ranging from Florida to North Carolina.

Around this same time… long, long ago, a bunch of friends and I were also working on a basic science recipe for understanding how oyster reefs work and it only contained a few ingredients: predatory fish frighten crabs and this fear protects oysters….a beautiful trophic cascade! But years later, we figured the recipe was too simple. So, we overhauled the recipe with many more ingredients and set about to test it from North Carolina to Florida with the scientific method.

Now that we finally digested a lot of data from our very big experiment (a.k.a. Cage Experiment 1.0), I can confidently say that the fear of being eaten does some crazy things to oyster reefs. And even though most of the ingredients were the same, those crazy things differed from NC to Florida. While our final recipe isn’t perfect, we now have a better understanding of oyster reefs and that the recipe definitely has many more ingredients.

For instance,

1. The fear of being eaten has a sound component to it. Previously, we thought fear was transmitted only chemically, but now we know that crabs can hear. This is huge!
2. Oyster filtration and oyster pooping can affect the amount of excess nutrients in our coastal environment. Our collaborator (M. Piehler, UNC-CH) showed that in some places, this can remove excess nutrients and that this services makes an acre of oyster reef worth 3,000 every year in terms of how much it would cost a waste water treatment facility to do the same job.
3. In a few months, I hope to update you on how sharks, catfish, drum, and blue crabs fit into the recipe.

In addition to uncovering some new ingredients, our pursuit of this basic science matters because it allowed us to figure out what methods and experiments work as well as what things don’t  (Watch how they reinvented one of their most depended upon tools: The spat tile experiment). In short, the fruits of this basic science project can now be shunted into applied science and the development of interventions to improve the Apalachicola Bay oyster fishery.

But given that the lack of oyster shell in the bay is clearly the problem and that re-shelling the bay would bring the oysters back, why do we need to conduct the research? Well, then again it could be the lack of fresh water coming down the Apalachicola River and/or the lack of nutrients that come with that fresh water. Oh, don’t forget about the conchs that are eating away at oyster reefs in St. Augustine, Florida and may be doing the same to those in Apalachicola.

Like the chicken piccata recipe, Apalachicola Bay is awesome, but it’s complicated. Clearly, there are lots of things that could be in play. But if we don’t understand how they are all linked, then we may waste a lot of effort because fixing the most important part with Ingredient A may not work without simultaneously fixing another part with Ingredient B. Even worse, maybe Ingredient B must come first!  Only through detailed monitoring and experiments will we figure out how all of the ingredients fit together.

Luckily, my brother shared the fruits of his basic culinary experiments so that I could quickly solve my applied problem: cooking a good dinner for the second date. Similarly, it’s great that we received funding from NSF to conduct our biogeographic oyster study, because now we can quickly apply the same methods and personnel to help figure out what’s ailing the Apalachicola Bay oyster fishery. Basic and Applied science, Yin and Yang.

–David

What’s next?

David’s colleague, Dr. Randall Hughes, takes us through another ecosystem that has been affected by drought in recent years, the coastal salt marsh.  As severe droughts become a normal occurrence, coastal ecosystems like marshes or the oyster reefs of Apalachicola Bay stand to take a beating.  Randall is looking at what makes a marsh stronger in the face of drought and other disturbances.

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

Waves and wind can make an underwater experiment challenging. But in Apalachicola Bay, it’s getting to where getting enough oysters to run an experiment is a challenge in itself. On Dimensions tonight (Wednesday, May 8 at 7:30 PM/ ET), get an inside look into what it’s like to go oystering during the oyster fishery crisis. We look at the men and women fighting for the bay, and the evolving alliance between those who work the bay, and those who would study it.

Hanna Garland FSU Coastal & Marine Lab

Growing up, I always loved to help my dad with the never-ending list of house and boat projects, but because being a perfectionist is not one of my attributes, it would bother me when he would remind me to “measure twice, cut once.” However, whether taken literally or figuratively, this saying has had more relevance as I have progressed through college and now my graduate career. Take for example: the Apalachicola Bay oyster experiment.

In January, we conducted habitat surveys in order to assess the condition of oyster reefs throughout Apalachicola Bay by quantifying the oysters themselves as well as the resident crustacean and invertebrate species. We found some interesting patterns, but this survey data is just a “snapshot” in time of the oyster reef communities, so we designed an experiment that will investigate the survivorship and growth of market-size oysters in the presence or absence of predators at 12 reefs across the bay.

Mimicking the design of most of the oyster experiments in the Hugbro lab, we continue to keep the marine epoxy, mesh, and rebar companies in business by securing oysters into predator-exposed or predator-excluded treatments and then installing them onto reefs. While the habitat surveys were conducted via scuba diving (or sometimes walking because the reefs were so shallow!), we decided to give our free-diving skills a test for the oyster experiment installation in order to reduce gear and research costs. Being primarily intertidal researchers we are not accustomed to all of the logistics for subtidal research, but free diving is mostly a mind game, right?

The gear needed for scuba diving (left) versus free diving (right).

Wrong! Meagan and I were reminded that we will never be greater than Mother Nature or “the elements.” We were only able to install the experiment on 10 of the 12 reefs throughout the bay and due to unfavorable weather conditions and diving logistics, we were unable to complete the installation on the remaining 2 reefs or check the status of the oysters that had already been deployed. As a result, we will be restarting this experiment in May, but this time via scuba and with learned knowledge and experience of working in the bay, which will allow us to obtain a more complete and accurate experimental data set.

These buoys mark experiment sites. Having the experiments submerged makes it otherwise invisible to passing boats and their propellors, and to oystermen and their tongs.

As frustrating as it may be to re-do the experiment, I was reminded at the recent Oyster Task Force meeting in Apalachicola, that the answer to the oyster crisis is going to take time; and in order to identify and quantify the environmental or biological stressors in the bay, research and management must be done correctly and entirely. So stay tuned, as there will need to be a lot more “measuring twice and cutting once” before we will be able to identify the key explanatory variables causing the loss of oyster habitat in Apalachicola Bay!

Music in the video by Nekronomikon Quartett.

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

Rob Diaz de Villegas WFSU-TV

The leaders of SMARRT look on as Dr. Karl Havens presents the Oyster Task Force's report.

This past Wednesday researchers from the University of Florida Oyster Recovery Team presented their report on the state of Apalachicola Bay to a public audience at the Apalachicola Community Center.  In the months since a Fishery Disaster was declared in the bay, this task force was formed by researchers from the University of Florida and our collaborator, Dr. David Kimbro (who was at Florida State University and is now at Northeastern).  They collected and analyzed historical sets of data and collected new data from the field to look at current conditions, their causes, and potential future actions aimed at restoration.  Here is a quick look at what was discussed:

• In his introductory presentation, Dr. Karl Havens (Director of Florida Sea Grant) included an image in his PowerPoint depicting how the Apalachicola/ Chattahoochee/ Flint Basin was affected by recent drought conditions.  He called attention to an area of extreme red, approximately over the Flint and Chattahoochee rivers in Georgia, stating that “in 2011, and 2012, it was the driest place in the entire United States.”  Those rivers feed the Apalachicola.
• Landings data (oyster harvest reported) show a sharp decline in oysters between August and September of 2012.  The suddenness of the decline, said Dr. Havens, is not consistent with overfishing, which results in a gradual drop. (Page 12 of the report)
• Dr. Steve Otwell cautioned that the reputation of Apalachicola oysters is being tainted by undersized oysters making it to restaurants.  It was acknowledged by representatives of SMARRT that certain individuals do harvest sub-legal oysters, and that a goal of SMARRT is to educate seafood workers about the legal catch sizes and the reasons behind them. When it comes to sub-legal oysters reaching consumers, Franklin County Seafood Workers President Shannon Hartsfield said, “It takes two.”  Someone has to harvest and bring a sub-legal oyster to the dock, and someone has to buy and sell it to restaurants.  SMARRT is the Seafood Management Assistance Resource and Recovery Team, an organization made up of seafood workers and buyers.
• The report finds that the three inch legal size is effective in preventing “size overfishing,” if it is properly enforced. (Pages 12-13)
• Concern was raised over out-of-state oysters replacing Apalachicola oysters in restaurants, and whether Apalachicola could regain the market.  Dr. Otwell pointed to Chesapeake Bay, which had its fishery collapse only to rebound as a premium product.
• Using their ECOSPACE modeling tool, they projected the recovery of the bay under several scenarios.  The worst case scenario has the bay recovering in 2020.  That’s with no shelling or reduction in harvesting.  Reducing effort in 2013 and 2014 would bring it back a couple of years faster, but the best scenario is a harvesting reduction and an increase in shelling (200 acres a year for 5 years).  That scenario predicts recovery by 2015. (Page 17)
• Three years after the Deepwater Horizon explosion, people are still concerned about the possibility of oil contaminated seafood.  Tests of oysters, blue crabs, shrimp and fish species showed little or no trace of chemicals associated with crude oil or dispersants. (Page 19)
• 

  Hanna Garland installs a rebar cage on the floor of the bay, in which her and David's experiments will be safe from oyster tongs and boat props. We will have videos explaining the experiment in the coming weeks.

  One goal of the Task Force is to set up ongoing sampling of the bay.  The Florida Department of Agriculture and Consumer Services (FDACS) has surveyed oysters living on the most harvested reefs in the bay, and that data was used in the computer modeling.  But where that work looked at number of oysters (legal and sub-legal), a more thorough look at conditions on the reef was deemed necessary.  That’s what David Kimbro and Hanna Garland have been working on.  They have already completed their survey of the bay and presented a snapshot of predator distribution, reef structure, oyster size, and of oyster mortality (Many of the oysters on the floor of the bay are “gapers.”  When they die, their shells open permanently).  You can read a brief summary of his results here.  Hanna is currently deploying an experiment featuring live oysters and spat tiles (watch a video on the Kimbro/ Hughes lab’s use of spat tiles here).  Through this, they will learn how spat (the next generation of oysters) and adults are surviving conditions in the bay, how well spat are growing, and how many are being eaten by predators.

• Dr. Otwell had an interesting solution to two problems: harvesting crown conchs.  Those who have followed this blog (or harvest oysters) know that crown conchs can become a real nuisance on oyster reefs (though a potential benefactor of the equally productive salt marsh system).  A crown conch fishery would provide some income for seafood workers while relaxing the effects of a predator that can get out of hand when the water gets saltier (like in recent drought conditions). (Page 28)

The queen conch (Strombus gigas) is a popular delicacy, but it is under current consideration as an endangered species. Interest is growing in using the related crown conch (Melongena corona, shown above) as a substitute meat.

The hope is that some of the partnerships and research work can continue despite a lack of funding, and even after the fishery recovers.  ”I’ve said it over and over and over again, most of our information comes from the really extreme low events,” said Dr. Bill Pine.  ”And we don’t know how these systems look during normal flow or high events.”  As he pointed out, research doesn’t always get done when the system is healthy, and that leaves gaping holes in the data.  Likewise, this unprecedented collaboration between seafood workers, the state agencies that manage the fishery, and the research community was created in crisis.  Will it survive as the fishery recovers?

Download a PDF of the full report here.

Coming up

The meeting on Wednesday was part of one of our busiest months of production for In the Grass, On the Reef.  This week alone, we went from one end of our viewing area to another, starting with an EcoAdventure on Slave Canal (towards the eastern end of our range) to Choctowhatchee Bay for a look at a different kind of oyster restoration project (that’s as far west as we air).  We tagged along on an oystering trip and got footage for videos dealing with another coastal ecosystem susceptible to drought: the salt marsh.  We’ve logged a lot of miles, and I have a lot of footage to put together.  Here is a preview:

David’s Apalachicola Bay research is funded by Florida Sea Grant.

In the Grass, on the Reef is funded by a grant from the National Science Foundation.

David and Randall’s NSF funded oyster study looks to understand how predators control oyster eating animals such as mud crabs and crown conchs. But this dynamic isn’t exclusive to oyster reefs. They are also investigating how predators might help maintain salt marshes and seagrass beds. In their seagrass bed studies, they have focused on a system loaded with predators: Bay Mouth Bar.

Tanya Rogers FSU Coastal & Marine Lab

The very first time I drove from Tallahassee to the FSU Coastal & Marine Lab I saw a black bear crossing the Crawfordville highway. No joke. This was in June of 2010, and I had just driven 5 days and 2800 miles from San Francisco to the Florida panhandle to take up my new job on the Gulf Coast. I had just finished college in Washington state, and I had never before been to the Southeast. What sort of wild place had I ended up in?

A very wild and unique one it turns out, and one I’ve come to know better working for the past few years as a research technician for Dr. David Kimbro in the fascinating coastal habitats of this region. Primarily I’ve been traipsing around oysters reefs across the state for the collaborative biogeographic oyster study (now drawing to a close), but for the past year or so I’ve also been managing our side project in the Bay Mouth Bar system, a sandbar and seagrass bed near the FSU Marine Lab. Bay Mouth Bar is a naturalist’s playground filled with surprises and an astonishing diversity of marine creatures that never ceases to amaze me. It is also a unique study system with an intriguing history out of which we can begin asking many interesting questions. This coming fall I’m excited to be starting as Dr. Kimbro’s Ph.D. student at Northeastern University, and for part of my dissertation I’ve decided to conduct some new experimental research this spring and summer out on Bay Mouth Bar.

A horse conch in Tanya's experiment consuming a banded tulip snail.

Bay Mouth Bar is known for its especially diverse assemblage of large predatory snails, which the ecologist Robert T. Paine conducted a study of in the late 1950′s. In 2010, we began surveying the snail community on the bar, interested in what changes might have occurred in the 50 years since Paine’s time, a period during which very little research had been done in this system. I began synthesizing some of the data we’ve gathered, as well as talking to some of the long-term residents of the area. So what has changed on Bay Mouth Bar since the 1950’s? A number of things in fact:

• Of the 6 most common predatory snail species, 2 are no longer present: the true tulip and the murex snail.
• The number of specialist snails (like the murex, which only eats clams) has declined relative to the number of generalist snails (those that eat a variety of prey, like the banded tulip).
• There has been a drastic reduction in the overall area of the bar and changes in the coverage seagrass, specifically the loss of large meadows turtle grass (Thalassia testudinum).
• Surface dwelling bivalves (e.g. scallops, cockles), once enormously abundant, are now very rare.

The two main snail species no longer found at Bay Mouth Bar, true tulip (The larger snail on the left, eating a banded tulip) and murex (right). The true tulip was, along with the horse conch, a top predator of the ecosystem, while the murex is a specialist snail, eating only clams.

Why is this interesting? Worldwide, we know that species diversity is declining as a result of human activities, that specialists are being increasingly replaced by generalists, and that consumer and predator species often face a disproportionate risk of local extinction. So what are the consequences of realistic losses and changes to biodiversity? Is having a diversity of predators beneficial (e.g. both horse conchs and true tulips) to an ecosystem as a whole? Do some species matter more than others? And how do the effects of predators depend on the type of habitat they’re in, given that habitats (like seagrasses) are also changing in response to the environmental changes? These are some of the questions I’m hoping to address in Bay Mouth Bar system, in which we have documented historical changes in predator diversity.

One of communities in Tanya's experiment. At the center are top predators reflecting either the current assemblage (a horse conch alone) or the historic assemblage (the horse conch and true tulip). The predators are tethered to posts and given enough line to reach the lower level predatory snails (murex, lightning whelks, banded tulips, and Busycon spiratum) on the outside. Those snails have enough line to get out of the large predator's reach and forage for food.

This past week, I set up an experiment featuring a menagerie of snails tethered in different assemblages across Bay Mouth Bar. Some assemblages mimic the current assemblage, whereas others mimic the assemblage found on the bar during Paine’s time. These historical assemblages include the snail species no longer found there, which I collected from other locations where they are still abundant. Some assemblages have top predators (e.g. horse conchs) whereas others do not. Some are in turtle grass, others are in shoal grass. We’ll see how, over the course of the summer, these different assemblages affect the prey community (clams, mussels, small snails) and other elements of seagrass ecosystem functioning.

Music in the piece by Donnie Drost.  Theme by Lydell Rawls.

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

Over the last few weeks, we’ve explored the ecology of fear in oyster reefs. What makes oysters too scared to eat, potentially keeping them from reaching market size or filtering water? What makes mud crabs too scared to eat oysters, giving the oysters a better chance to succeed? New research by Dr. Randall Hughes and Dr. David Kimbro might change the way we understand fear in mud crabs.

Dr. Randall Hughes FSU Coastal & Marine Lab

When we started the In the Grass, On the Reef project, Rob (WFSU-TV Producer Rob Diaz de Villegas) embarked on a crash course learning about oyster reefs and salt marshes, biodiversity, and non-consumptive predator effects.  While you’re most likely familiar with those first few terms, the last one – non-consumptive effects – is a bit of a mouthful and hasn’t exactly made the list of new slang words of 2013.  The term refers to the ability of predators to SCARE their prey even when they don’t EAT them, causing the prey to hide, or eat less, or change their size/shape to make it less likely that they will be eaten.  Of course, these changes are only possible if the prey realizes the predator is there before getting eaten!  There are several “cues” that prey can use: (1) they can see them (visual cues); (2) they can feel them (physical cues); or (3) they can “smell” them (chemical cues).  This last category is really common in the ocean, especially with slimy snail or fish predators that give off lots of chemicals into the water!

As Rob was learning more about the fish predators that we find on our oyster reefs, he discovered audio clips of the sounds that several of these fish make.  Putting 2 and 2 together, he posed a simple question to David and me: Can mud crabs use fish sounds as a cue that their predators are near?

Housam collecting juvenile clams attached to oyster shells for use in the experiment.

To be quite honest, David and I didn’t have an answer.  But, we knew how to find out – do the experiment(s)!  We enlisted Housam Tahboub, an undergraduate at the University of Michigan Flint, who wanted to do his summer Honors project in our labs.  (Little did he know what he was getting into.)  And then we set off on a crash course in bioacoustics, underwater speakers, and crab torture chambers (more on that in a minute).

Rob’s question really has 2 parts:
(1) Can crabs hear (anything)? (They don’t have ears.)
(2) Do crabs respond to the sounds of their fish predators?

A mud crab ready for his hearing test.

To answer #1, we paired up with Dr. David Mann at the University of South Florida. Dr. Mann is an expert in bioacoustics, and particularly in evaluating whether marine critters (primarily fish) can hear different sounds. We modified his methods slightly to accommodate our crabs – basically, we needed to immobilize the crabs on a ‘stretcher’ so that we could insert one electrode near the crab’s antennae, and another in the body cavity to pick up any background “noise” the crab may be produce that was not in response to the acoustic stimuli. Although I know it looks like crab torture, all the crabs survived the experiment!

A crab submerged in the acoustic chamber.

Once the crab was immobilized and the electrodes were in place, we submerged the crab in a tank full of seawater that had an underwater speaker in it. We then played a series of acoustic stimuli of different volumes and frequencies and quantified the response recorded by the electrode. The really nice thing about this method is that we don’t have to train the crabs to tell us when they hear the noise like in the hearing tests that you and I take!

A marked oyster shell with juvenile clams glued on it as a crab buffet.

To tackle question #2, we set up a mesocosm experiment at FSUCML. Each mesocosm (aka, bucket) had sediment, a layer of loose oyster shell to serve as habitat for the crabs, and 5 mud crabs that we collected from nearby oyster reefs. We also added some juvenile clams glued to a few marked oyster shells in each mesocosm – this way, we could count the number of clams eaten over time and determine whether crabs were eating more or less in response to the predator sounds.

To run the experiment, we downloaded sound clips of several different crab predators – toadfish, black drum, and hardhead catfish – as well as 2 non-predators to serve as controls – snapping shrimp and a silent recording. Housam put these on his iPod, connected it to an amplifier and underwater speaker, and we were ready to begin.

(Well, let’s be honest, it wasn’t quite that simple. Housam read a lot of papers to figure out the best methods, spent lots of time collecting crabs, and logged lots of hours (both day and night, in the company of mosquitoes and biting flies) moving the speaker from tank to tank before we finally settled on a good protocol. He even tried all of this in the field! But when his summer ended, Tanya, Phil, and Ryan kindly stepped in to run the rest of the trials we needed.)

But we didn’t stop there. We know from our earlier experiments with Kelly Rooker (another undergraduate researcher) that the crabs don’t eat as much when exposed to water that hardhead catfish have been swimming in, most likely because they can detect chemicals in the water that the fish give off. So which cue generates a stronger response – chemical cues or sound cues? Time for another experiment!

Phil checks on the mesocosm experiment at FSUCML

In this version, the mesocosms were assigned to one of 4 combinations: (1) a silent recording, paired with water pumped from a tank holding 2 hardhead catfish into the mesocosm; (2) a recording of a hardhead catfish, paired with water that did not go through the catfish tank; (3) a recording of a hardhead catfish, paired with water from the catfish tank; (4) a silent recording, paired with water that did not go through the catfish tank. We again looked at the number of clams eaten over time to see how the crabs change their behavior.

This project has been a lot of fun, and it never would have happened were it not for Rob’s curiosity. We gave a preview of our results at the Benthic Ecology conference in Savannah, GA, last weekend. But we’ll have to wait until everything is reviewed by other scientists and published in a scientific journal before we can share all of the details here. So stay tuned!

Music in the piece by zikweb.

Black Drum recording used in the video courtesy of James Locascio and David Mann, University of South Florida College of Marine Science.

Catfish and toadfish recordings copyright University of Rhode Island.  They were obtained from dosits.org, under these terms:

Copyright 2002-2007, University of Rhode Island, Office of Marine Programs. All Rights Reserved. No material from this Web site may be copied, reproduced, re-published, uploaded, posted, transmitted, or distributed in any way except that you may download one copy of the materials on any single computer for non-commercial, personal, or educational purposes only, provided that you (1) do not modify such information and (2) include both this notice and any copyright notice originally included with such information. If material is used for other purposes, you must obtain permission from the University of Rhode Island. Office of Marine Programs to use the copyrighted material prior to its use.

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

For today’s post, we shift our look at the ecology of fear from oyster reefs to the (often) neighboring salt marsh.  We know crown conchs are villains on oyster reefs, but might they redeem themselves “in the grass?”  If they live on the Forgotten Coast, it depends on what side of Apalachicola they live.

Dr. Randall Hughes FSU Coastal & Marine Lab

The Crown Conch (Melongena corona).

If you’re a fan of oysters and you read David’s previous post, then you probably don’t like crown conchs very much. Why? Because David and Hanna’s work shows that crown conchs may be responsible for eating lots of oysters, turning previously healthy reefs into barren outcrops of dead shell.  And we generally prefer that those oysters be left alive to filter water and make more oysters.  And, let’s be honest, we would rather eat them ourselves!

But, in something of a Dr. Jekyll and Mr. Hyde act, crown conchs can take on a different persona in the salt marsh. Here, the exact same species acts as the good guy, increasing the abundance of marsh cordgrass.  And more abundant marsh plants generally means more benefits for we humans in the form of erosion control, water filtration, and habitat for the fishes and crabs we like to eat.  How exactly does that work?

The Marsh Periwinkle (Littoraria irrotata).

If you look out in a salt marsh in much of the Gulf and Southeast Atlantic, I can nearly guarantee that you’ll see a marsh periwinkle snail. Usually, you’ll see lots and lots of them. These marine snails actually don’t like to get wet – they climb up the stems of the marsh grass as the tide comes in. While they are up there, they sometimes decide to nibble on a little live cordgrass, creating a razor blade-like scar on the plant that is then colonized by fungus. The periwinkles really prefer to eat this fungus instead of the cordgrass, but the damage is done – the fungus can kill the entire cordgrass plant! So these seemingly benign and harmless periwinkles can sometimes wreak havoc on a marsh.

But wait a minute – if periwinkles cause all the cordgrass to die, then why do you still see so much cordgrass (and so many snails) in the marsh? That’s where the crown conch comes in.

At the edge of a marsh at high tide, a crown conch approaches a periwinkle snail. As shown in the video above, the conch was soon to make contact with the smaller snail and send it racing (relative term- the video is of course sped up) up a Spartina shoot.

In marshes along the Gulf coast, there are also lots of crown conchs cruising around in the marsh (albeit slowly), and they like to eat periwinkles. Unlike other periwinkle predators such as blue crabs, the crown conchs stick around even at low tide. So when the periwinkles come down for a snack of benthic algae or dead plant material at low tide, the crown conchs are able to nab a few, reducing snail numbers. And fewer snails generally means more cordgrass.

Of course, the periwinkles aren’t dumb, and they often try to “race” away (again, these are snails!) when they realize a crown conch is in the neighborhood. One escape route is back up the cordgrass stems, or even better, up the stems of the taller needlerush that is often nearby. By causing periwinkles to spend time on the needlerush instead of grazing on cordgrass, or by making the periwinkles too scared to eat regardless of where they are sitting, the crown conch offers a second “non-consumptive” benefit for cordgrass. One of our recent experiments found that cordgrass biomass is much higher when crown conchs and periwinkles are present compared to when just periwinkles are present, even though not many periwinkles were actually eaten.

On the other hand, if the periwinkles decide to climb up on the cordgrass when they sense a crown conch, and if they aren’t too scared to eat, then crown conchs can actually have a negative effect on the plants. This is exactly what David found in one of his experiments.  In this case, the tides play an important role – west of Apalachicola, where there is 1 high and 1 low tide per day, each tide naturally lasts longer than east of Apalachicola, where there are 2 high tides and 2 low tides per day.  The longer tides west of Apalach appear to encourage the snails not only to stay on the cordgrass, but also to eat like crazy, and the plants bear the brunt of this particular case of the munchies.

So even in the marsh, it turns out that crown conchs can be both a friend and a foe to marsh cordgrass, depending on how the periwinkles respond to them. And figuring out what makes periwinkles respond differently in different situations just gives us more work to do!

Music in the piece by Revolution Void.

In the Grass, On the Reef is funded by a grant from the National Science Foundation.

Lately, the Hugh-Bro (Hughes and Kimbro) Lab has covered a lot of miles.  Dr. David Kimbro and Dr. Randall Hughes have accepted positions at Northeastern University in Boston.  Tanya Rogers is David’s first graduate student at NEU, though her dissertation is on Bay Mouth Bar at the mouth of Alligator Harbor.  Hanna Garland (who had spent a year living in Saint Augustine Beach for her graduate work with David) and Stephanie Buhler are covering Apalachicola Bay, though Stephanie will start her PhD. work in the Bahamas soon.  We’ll let Ryan Coker tell you of his East coast adventures helping Meagan Murdock wrap her National Park Service tile experiment…

Ryan Coker FSU Coastal & Marine Lab

Timucuan - Here I am inspecting a tile as we made our way to the next reef. Looks like these particular oysters didn't fare well, but we saw plenty that did!

For the last couple months, a lot of my responsibilities around the lab have shifted from working out in the field to processing samples from our salt marsh projects (recently, measuring the organic content of sediment samples, i.e. setting dirt on fire and calculating the missing weight). This past week I was happy to be recruited from my normal lab duties to help out on Meagan’s National Park Service oyster experiment, recovering our oyster-covered paving bricks from the experimental reefs for analysis. This meant packing my bags to leave for a six-day field trip to visit our reef sites at Timucuan Ecological & Historic Preserve in Jacksonville and Cumberland Island National Seashore, a barrier island off of Georgia’s coastline. I was told to prepare for precarious treks through oystershell, leg-swallowing mud, and swarms of no-see-ums who, in spite of their name, were determined to get noticed. I prepared for these challenges in earnest, with thick boots and quick feet and enough bug spray to at least suggest that eating me alive wasn’t in any insect’s best interest. But what I wasn’t ready for was the sheer beauty of these places. I feel immensely lucky to have found my calling in ecology—I do the work I love, and I get to do it in the loveliest places.

Timucuan - Meagan decided to test the depth of this mudflat to see if we could access one of our oyster reefs at very low tidal height. As she progressed downward at a rate far exceeding her forward gains, it was clear that we were going to have to wait out the tide and try again. Thank you, Meagan, for being such a champ and getting completely mud-covered while I waited on the boat, laughing and taking pictures. Here she is using my leg to pull herself out of the muck as I perched on the ledge of the pontoon boat.

Because we had a free half-day on Cumberland Island while we waited for the National Park Service to come and ferry us back to the mainland, Meagan and I set off to explore the island. We traded our boots and waders for sneakers and shorts long, bug-proof pants. Transitioning from a field tech to a tourist for just a few hours, I ran up and down the island in an attempt to see it all. It was gorgeous.

The forest was intercut with dirt paths canopied by towering palms and the twisting limbs of immense Live Oaks. The infinite beach, its width rolled out flat from delicate high-blown dunes to where it dips below the lapping ocean tide, is home to shorebirds and “wild” packs of roaming horses.

What I found most striking, though, were the crumbling skeletal remains of Dungeness, a mansion built in the 1880s, abandoned in 1925, and burnt to ruins by the 1960s.

Imagining this place in its glory, I filled in the gaps of the walls and floors where they were collapsed and covered by weeds and rubble. There’s not much left, and I didn’t dwell on my fiction overmuch, but I sure would have loved to see that mansion as it stood. It made me think about the impacts we make on the world, the legacies we’re trying to build before we go. I feel really good about the work I contribute to in the lab. To the metaphorical library of scientific knowledge, I’d like to think the work I do is helping to add-on another room. We’re in the ecology wing, expanding it out, adding just a bit to the collection. It’s our mansion, and at the very least, it’s fireproof.

Of course, mostly I just thought “Holy cow, this is gorgeous,” as I snapped away, already daydreaming about the next spectacular place I might have the opportunity to visit with the lab.