oysterreefpage

Meet the Species “On (and swimming around) the Reef”

IGOR chip- habitat 150The species on this page are typical of north Florida oyster reefs. Dr. David Kimbro, Dr. Randall Hughes, and their colleagues are conducting an NSF funded study into predators and predator effects on oyster reefs. In addition, Dr. David Kimbro and his graduate student, Hanna Garland, are researching the drought-stricken oyster reefs of Apalachicola Bay. Included in the descriptions of species are links to blog posts related to both studies.

Foundation Species

oyster clumpAmerican Oyster (Crassostrea virginica) also known as the Eastern Oyster
Like the smooth cordgrass is the foundational species of a salt marsh, the oysters that comprise a reef create an ecosystem.  Click to expand

Like the smooth cordgrass is the foundational species of a salt marsh, the oysters that comprise a reef create an ecosystem.  Oysters can grow on any hard surface in the intertidal zone, though larval oysters tend to seek out the chemical signature of other oysters, landing on their shells.  Once a larval oyster recruits to a surface, it is called spat. As oysters build their shells on other oyster’s shells, they create a reef structure which benefits the oysters as well as the many species that seek refuge within it.
Oyster Reef in Alligator Harbor

They provide shelter for a number of predators and prey, and themselves are prey of animals like the mud crab and the oyster drill (and humans). The oyster is a filter feeder, consuming phytoplankton swimming in the water. Through that process, the oyster removes nitrogen from the water, potentially preventing algal blooms that harm other marine animals.
IMG_3365

The oysters studied in David and Randall’s NSF study are intertidal, meaning that they are exposed at low tide.  These tend to grow smaller than subtidal oysters like those in Apalachicola Bay, which remain submerged and are commercially harvested.

Statewide Commercial Landings
2011: 2,663,406 lbs., $7,433,553
2010: 2,198,996 lbs., $6,435,814
2009: 2,915,440 lbs., $7,111,862

Top Predators

David Kimbro holds catfish Hardhead Catfish (Arius felis)
In north Florida, catfish are dominant predators in the oyster reef ecosystem. Click to expand

Its whiskers, known as barbels, are used to find small fish, crabs, and shrimp.  On north Florida oyster reefs, their primary importance is as a predator of mud crabs.  By eating and scaring mud crabs, they regulate the crab’s ability to consume oysters.
David Kimbro holds catfish

Sail Catfish Sail Catfish (Bagre marinus)also known as the Gafftopsail catfish
Similar to the Hardhead catfish, the gafftopsail is distinguished by its venomous spines.  Click to expand

Similar to the Hardhead catfish, the gafftopsail is distinguished by its venomous spines. Like the hardhead, it is an omnivore with a preference for crustaceans like blue crabs and mud crabs.
Sail Catfish

Toadfish Toadfish (Opsanus tau)also known as the ugly toad and the oyster cracker
The toadfish is a primary predator of mud crabs on the North Carolina reefs where Dr. David Kimbro and Dr. Randall Hughes began their research careers.  Click to expand

These omnivores grow between 30-38 cm, and prefer to eat crabs such as hermits and mud crabs.

The toadfish is a primary predator of mud crabs on the North Carolina reefs where Dr. David Kimbro and Dr. Randall Hughes began their research careers.  Though toadfish are native to Florida waters, Hardhead and Sail Catfish are more usually the dominant predator of north Florida reefs.
Toadfish

Blue Crab Blue Crab (Callinectes sapidus)
A popular delicacy in this habitat is the blue crab, which is the crab used to make Maryland crab cakes. Click to Expand

A popular delicacy in this habitat is the blue crab, which is the crab used to make Maryland crab cakes. Increasingly, Maryland imports their crabs from Florida, which has more robust habitats for them. On oyster reefs and in salt marshes, blue crabs are important predators that help control populations of oyster drills, mud crabs, and periwinkle snails.

2011 Statewide Commercial Landings
Hard-Shell Blue Crab: 10,018,045 lbs., $11,434,093
Soft-Shell Blue Crab: 74,926 lbs., $562,425

Blue Crab

Stone Crab in Wakulla BeachStone Crab (Menippe mercenaria)
Stone crabs have strong, meaty claws that are used to crush oysters.  Click to expand

Stone crabs have strong, meaty claws that are used to crush oysters. These claws are eaten by humans and are commercially valuable. Stone crabs also occupy multiple trophic levels on the oyster reef.  They eat both oysters, the foundation species, and many of the oyster’s predators, including crown conchs, mud crabs, and oyster drills.

Stone Crab in Wakulla Beach

Stone crabs make their home by crushing a section of oyster reef, creating a burrow within it.

Stone Crab Burrow

Oyster Predators

Atlantic oyster drill on an oyster reef Atlantic Oyster Drill (Urosalpinx cinerea)
Oyster drills use their radula to bore holes into oysters and clams. Click to expand

Oyster drills use their radula to bore holes into oysters and clams.  This species is found on the Kimbro/ Hughes sites on Florida’s Atlantic coast.  The larger southern oyster drill has become a problem in Apalachicola Bay.

Atlantic oyster drill on an oyster reef

Southern oyster drill in Apalachicola Southern Oyster Drill (Thais haemastoma)
This oyster drill species is a problem in commercial oyster fisheries, and large numbers have been found in Apalachicola Bay.   Click to Expand.

The southern oyster drill pictured here was captured in Apalachicola Bay, where higher salinity induced by drought conditions has created an environment hospitable to oyster predators such as drills and crown conchs.

Southern oyster drill in Apalachicola

crown conch on Saint Augustine oyster reef Crown Conch (Melongena corona)
Crown conchs consume oysters by inserting their proboscis between an oyster’s valves.  Click to expand

The crown conch is a main predator of the Gulf Coast salt marsh, feeding on periwinkle snails.  This helps control periwinkle numbers, benefiting the marsh habitat.  Crown conchs play a different role on oyster reefs, consuming oysters by inserting their proboscis between the oyster’s valves.  Conchs thrive in higher salinity water, and can overrun a drought-stricken oyster reef.  In Apalachicola Bay, as in Saint Augustine, the crown conch afflicts intertidal oyster reefs.  Apalachicola’s commercially harvested subtidal reefs are infested (as of early 2013) with a different snail, the southern oyster drill.

David Kimbro presents his team’s findings regarding oyster predators in Apalachicola Bay.  Click here here for more.

crown conchs on Saint Augustine oyster reef

Banded Tulip Banded Tulip (Fasciolaria hunteria)
The banded tulip is a predator that feed on oysters as well as bivalves such as clams.  Click to Expand

The banded tulip is a predator that feeds on oysters as well as bivalves such as clams.
Banded tulip

mud crab on Alligator Harbor oyster reef Mud Crab (Panopeus sp.)
Panopeus species range in size from the miniscule herbstrii to larger individuals closer in size to stone crabs. Click to expand

Panopeus species range in size from the miniscule herbstrii to larger individuals closer in size to stone crabs.  Their hefty claws are ideal for tearing through young oyster shells to consume their meat. Mud crabs are in turn consumed by stone crabs, toadfish, catfish, and blue crabs
.mud crab on Alligator Harbor oyster reef

Other Species In & Around the Reef

black drum in net Black Drum (Pogonias cromis)
The largest of the drum family, the black drum is common in brackish waters such as those in which oyster reefs are found.  Click to Expand

The largest of the drum family, the black drum is common in brackish waters such as those in which oyster reefs are found.  The black drum eats crustaceans, mollusks, and fish.
2011 Statewide Commercial Landings
29,387 lbs., $25,090

black drum in net

Lightning Whelk by an Alligator Harbor oyster reef Lightning Whelk (Busycon contrarium)
Like the crown conch, the lightning whelk uses its proboscis to pry bivalves open and suck out the flesh.  Click to expand

Like the crown conch, the lightning whelk uses its proboscis to pry bivalves open and suck out the flesh. These whelks can be easily confused for knobbed whelks, with which it shares many characteristics. The best way to visually differentiate the two is by identifying on which side it curves. Lightning Whelks curve on the left, knobbed whelks on the right. However, knobbed whelks are only found in the Atlantic.

Lightning Whelk

pigfish Pigfish (Orthopristis chrysoptera)

 

pinfish Pinfish (Lagodon rhomboides)
The pinfish gets its name from the sharp spines in its dorsal fin.  Click to expand

The pinfish gets its name from the sharp spines in its dorsal fin. It is a main food of the gag grouper, and is a popular bait fish. So, while it is not directly consumed by humans, it is an important part of our own food web.
2011 Statewide Commercial Landings
69,490 lbs., $177,265

pinfish

 

Red Drum (redfish)Red Drum(Sciaenops ocellatus) also known as Redfish, Channel Bass, Spottail Bass, or Reds
The red drum is a popular catch for the sport fisherman, and is widely consumed by humans.  Click to expand

The Red Drum is very similar its close relative, the black drum, and both species are found around each other in brackish waters.  The red drum is a popular catch for the sport fisherman, and is widely consumed by humans.

Red Drum (redfish)

Red SnapperRed Snapper (Lutjanus campechanus)
As juveniles, red snapper often use oyster reefs for refuge.  Click to expand

As juveniles, red snapper often use oyster reefs for refuge.

Red Snapper

Silver PerchSilver Perch (Bairdiella chrysoura)

 

Snapping Shrimp Snapping Shrimp (Alpheidae family)
Snapping shrimp are known for their claws which make a “popping” sound that can be heard on intertidal oyster reefs.  Click to expand

Snapping shrimp are known for their claws which make a “popping” sound that can be heard on intertidal oyster reefs. The pressure created by the pop is enough to kill a small fish.

Snapping Shrimp

striped mullet Striped mullet (Mugil cephalus)
Striped mullet is an international fish, found along coastlines of every continent except Antarctica. Click to expand

Striped mullet is an international fish, found along coastlines of every continent except Antarctica. Along the Forgotten Coast, mullet spend their juvenile years in salt marshes. There they find shelter from predators. As an adult, one of its main predators are humans, who value it as both food and bait. Mullet carrying roe are especially prized and are worth much more at fish markets.

striped mullet

Hermit Crab in St. AugustineThinstripe Hermit Crab (Clibinarius vittatus)
Hermit crabs occupy gastropod shells of all kinds, either finding them empty or attacking occupied shells. Click to Expand.

Hermit crabs occupy gastropod shells of all kinds, either finding them empty or attacking occupied shells.  Dr. David Kimbro’s graduate student, Hanna Garland, had noticed that they were often a predator of crown conchs in the oyster reefs south of Saint Augustine.  Those reefs had been overrun with the conchs.  Read more about Hanna Garland’s Hermit Crab/Crown Conch Cage Matches here.

Hermit Crab in St. Augustine

Spot (Leiostomus xanthurus)
Click to expand.

2011 Statewide Commercial Landings
35,822 lbs., $21,349

 

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