Tag Archives: oyster reef

Bird Watching & Nature Writing: Susan Cerulean at Bald Point

Video: bird watching, nature writing, and possibly the best sunrise spot on the Forgotten Coast. Author Susan Cerulean joins us at Bald Point State Park.

Rob Diaz de Villegas WFSU-TV

Susan Cerulean and I are watching a bufflehead duck dive for food by an oyster reef.  We’re at Bald Point State Park, and Susan is putting me in tune with nature’s cycles.  “You can’t know when that last one’s left,” she says of the duck, which should soon be departing for the north.  This is the seasonal cycle, warming and cooling that spurs many of the birds we’re seeing to start continental and intercontinental flights. Continue reading

Can crabs hear? (Revisited, with answers!)

P1050260Four years ago, we traveled out into the oyster reefs of Alligator Harbor with Dr. David Kimbro.  It was both the start of an ambitious new study and of our In the Grass, On the Reef project.  Last June, we went back to those reefs with Dr. Randall Hughes as she, David, and their colleagues revisited study sites from North Carolina to the Florida Gulf.  In 2010, they sampled the reefs with nets and crab traps, and harvested small sections of reef.  This more recent sampling, which unfolds in the opening scenes of our recent documentary, Oyster Doctors, was conducted with underwater microphones.  Randall explains how sound became a tool in further understanding fear on oyster reefs.

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The research in the following post was conducted while Randall and David worked at the FSU Coastal and Marine Laboratory.

Dr. Randall Hughes Northeastern University

A little over a year ago, I wrote about our research project, motivated by a question from WFSU producer Rob Diaz de Villegas, to test whether crabs can hear the “songs” made by their fish predators. At the time, the work had not been published, and so I was not able to share all of the juicy details. But now it has, in the Proceedings of the Royal Society B, so I can finally answer with a resounding YES! Continue reading

RiverTrek 2013 Preview: A Year in the Apalachicola River and Bay

Rob Diaz de Villegas WFSU-TV

RiverTrek paddlers are raising funds for the Apalachicola Riverkeeper, an organization whose mission is to “provide stewardship and advocacy for the protection of the Apalachicola River and Bay, its tributaries and watersheds…” (participating media members do not raise funds).  At the end of the paddle, on October 12, there will be a reception in Battery Park in Apalachicola.  There, people can greet the paddlers and bring non-perishable food items in benefit of Franklin’s Promise.  Franklin’s Promise aids the families affected by the failure of the Apalachicola Bay oyster reefs.

IGOR chip- gastronomy 150“The Good Lord giveth, and Georgia and the Corps taketh away.” Those words were spoken by Jon Steverson, Executive Director of the Northwest Florida Water Management District.  He was testifying before Florida senators Bill Nelson (D) and Marco Rubio (R) during a special field hearing to address the collapse of the Apalachicola Bay oyster fishery.  The high-profile event, held two weeks ago in Apalachicola, marked almost one year into a particularly turbulent era for this region.  Just one year ago, I was preparing to kayak the Apalachicola River for RiverTrek 2012.  The winter bars in the bay were just days away from opening.  When they did, a lot changed, including the nature of the RiverTrek videos we were to make, and the In the Grass, On the Reef project as a whole. Continue reading

Shark tooth found in Apalachicola Bay buoy marking oyster reef experiment.

Apalachicola Oyster Research: SHARK WEEK

Since they’ve deployed their experimental cages in Apalachicola Bay, David Kimbro’s crew has had some go missing, while others have been found in this condition.  Missing buoys make potentially unharmed cages nearly impossible to find.  Until just yesterday, there have been no leads as to the identities of possible culprits.

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

Shark week? In Apalachicola Bay, oyster drills like this one are the animals that have inflicted the most damage.

I’ll eventually get to how our research on Apalachicola Bay oysters ties into shark week. But first, let me tell you about my history with the annual Shark Week, which is put on by the Discovery Channel. Growing up as a surfer in North Carolina, the best time to surf was in the late summer and early fall. After many warm months of zero waves in the spring and summer, we lived for tropical storms that would make their way into the south east….but not get too close. I hated those suckers that got too close, because fun waves would quickly turn into pigs being on the roof and lots of misfortune for my fellow North Carolinians. Continue reading

Oyster Research Needs Your Help In Apalachicola Bay

Oyster drills infest one of David Kimbro's Apalachicola Bay experimental spat tile cages.

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.

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.

Recycling Oyster Shells for Choctawhatchee Bay

Rob Diaz de Villegas WFSU-TV
Choctawhatchee Basin Alliance 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.

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.

IGOR chip- sedimentation 150

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.  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.

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.

Oyster tongs and cull board, Apalachicola Bay.

Researchers and Oystermen Fighting for Apalachicola Bay

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

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

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. Continue reading

The Apalachicola Bay Situation Report: A Quick Take

Rob Diaz de Villegas WFSU-TV
The leaders of SMARRT look on as Dr. Karl Havens presents the Apalachicola Bay Oyster Task Force's report.

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 oyster fishery.  The Apalachicola Community Center was filled with concerned locals, many of which were oystermen.  They were looking for news on the crash of the fishery and recommendations for future action.

The task force is made up of UF researchers and our collaborator, Dr. David Kimbro of Northeastern University (and until recently, Florida State University).  They collected and analyzed historical sets of data on the health and abundance of oyster stocks in the bay, and added current field observations.  This data was then used to create a model which would predict the success of restoration efforts under different flow conditions on the Apalachicola River. Continue reading

A mud crab ready for his hearing test.

Can crabs hear? (A testament to the benefits of collaboration)

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

IGOR chip_ predators_NCE 150When 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.

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 mud crab submerged in the acoustic chamber

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.

Notes From the Field: Hermit Crab/Crown Conch Cage Match

Last week David connected the regional dots, noticing similarities in oyster reefs overrun by oyster eating crown conchs across North Florida, from the Matanzas Reserve south of Saint Augustine to Apalachicola Bay. That included a breakdown of what they found during surveys of the Bay. Below, Hanna Garland details one of her experiments mentioned by David in the post.
Hanna Garland FSU Coastal & Marine Lab

Gaining a better understanding of the beautiful yet complex habitats that border our coastlines require a significant amount of time surveying and manipulating organisms (as you may know if you have been following our research for the past three years!), and even so, there can still be limitations in whether or not we truly know what is “naturally” occurring in the system.  Unfortunately, pristine salt marshes, seagrass beds and oyster reefs are in a general state of decline worldwide; however, this only heightens our incentive to investigate further into how species interact and how this influences the services and health of habitats that we depend on for food and recreation.

For the past two and a half years we have been studying the oyster populations along 15km of estuary in St. Augustine, but it did not require fancy field surveys or experiments to notice a key player in the system: the crown conch.  Present (and very abundant!) on oyster reefs in the southern region of the estuary, but absent in the northern region, it was obvious that there were interesting dynamics going on here…and we were anxious to figure that out!

In hopes of addressing the question: who is eating whom or more importantly, who is not eating whom, we played a game of tether ball (not really!) with nearly 200 conchs of various sizes by securing each one to a PVC pole (with a 1m radius of fishing line for mobility) onto oyster reefs.  After six months (and still ongoing), the only threat to the poor snails’ survival appeared to be the thinstripe hermit crab (Clibinarius vittatus)!

Hypothesized that hermit crabs invade and occupy the shell of a larger crown conch in order to have a better home, we decided to further investigate the interactions between crown conchs and hermit crabs by placing them in a cage together (almost like a wrestling match).

After only a few days, the mortality began, and results showed a weak relationship between species and size, and appeared to be more of a “battle of the fittest”.

The implications of how the interactions between crown conchs and hermit crabs influence the oyster populations are still largely unknown, but knowing that neither species have dominance over one another is important in understanding the food webs that oyster reefs support…and that organisms occupying ornate gastropod shells can be lethal as well!

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