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Carnivory hot buttons for carnivory part of Biology of Caribbean Coral Reefs website hot button for zooplanktivore part of BCCR hot button for spongivore part of BCCR hot button for corallivores & other cnidivores part of BCCR hot button for gorgonivores part of BCCR hot button for benthic invertebrate-eaters part of BCCR hot button for piscivores part of BCCR
This part of carnivory deals with benthic invertebrate-eaters, that is, with coral-reef organisms, in this case, mainly fishes, that eat benthic (bottom-dwelling) invertebrates. Other topics relating to carnivory on coral reefs can be accessed via the icons.
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of feeding grunts taken from a video "As we continue the dive through this lovely reef, you might wonder...where are all the motile reef invertebrates? But many of these fish eat things like crabs and snails and worms, so it's no wonder that their prey tend to hide away during the day and only come out at night." - Turks & Caicos 2005
 
 

Carnivory: benthic invertebrate-eaters: eaters of sea urchins

About 40% of all reef fishes feed on benthic invertebrates, excluding those that eat cnidarians. Prey types include sea urchins and brittle stars, considered in this section, and SHELLFISHES, and SQUIDS & OCTOPUSES, found in their own section. The selection of invertebrate prey is not meant to be complete, but just to give a sampling of the diets of some of these carnivorous fishes.

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a black sea urchin Diadema antillarum taken from a video

"Sea urchins appear well able to take care of themselves...yet, they do have a few specialised, shall we call them brave, predators." - Bonaire 2003

NOTE black sea urchin Diadema antillarum

 
 

photograph of a toadfish
Toadfishes in Panama related to the one shown here subsist almost entirely on black sea urchins. If small, the urchins are sucked rapidly into the mouth in their entirety; larger ones are sucked in with some spine breakage. Prior to the demise of sea urchins in the Caribbean in late 1983, toadfishes alone were thought to consume 20,000 urchins per hectare per year on certain Panamanian reefs. This is equal to one per fish per day. Hoffman & Robertson 1983 Bull Mar Sci 33: 919. Photograph courtesy Anne Dupont, Florida.

 


This toadfish Sanopus splendidus is endemic to Cozumel,
Mexico but presumably also eats sea urchins 1.5X

  Spanish hogfishes also eat sea urchins:
 
photo collage showing various acts of predation by Spanish hogfishes Bodinianus rufus on sea urchins
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of queen triggerfish taken from a video

"Queen triggerfishes certainly are handsome. They eat sea urchins and other shellfish. I wonder if their set-back eyes are for protection from the spines of their prey?" - Bonaire 2003

NOTE Balistes vetula

 
  photo collage of fishes that eat sea urchins
Fishes that prey on sea urchins are triggerfishes, porcupinefishes, and balloonfishes.
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a pocupinefish taken from a video

"Here's another fish...a porcupinefish, that is known to eat sea urchins when it's not busy with its normal diet of molluscs. Check out those jaws. A diver in Florida lost his little finger to a balloonfish not so long ago." - Bonaire 2003

NOTE Diodon hystrix

 
 

photograph of southern stingray Dasyatis americanaphotograph of heart urchin Meoma ventricosus
Heart urchins are likely preyed upon by stingrays, eagle rays, and other fishes that dig in the sand.

Partially buried heart urchin
Meoma ventricosus 0.5X

 

 

Southern stingray Dasyatis americana
in company with a bar jack Caranx
ruber
hunt for buried prey 0.15X

 

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of southern stingray with a bar jack

"Because of their habit of snuffling through sand looking for molluscs and fish prey, stingrays would likely commonly encounter heart urchins. It's surprising, then, that there are so few references to them being eaten by stingrays." - Cayman Brac 2003

NOTE southern stingray Dasyatis americana with a bar jack Caranx ruber

 
 


Another species of ray that subsists on benthic invertebrates, including worms, sea anemones, and other soft-bodied forms, is the torpedo or electric photograph of an electric ray Narcine brasiliensis ray. However, when it encounters something live and edible in the sand as it snuffles along, it does not stun the prey with an electrical charge; rather, this handy capability is saved for the ray's own predators. Instead, it uses its highly extensible jaw apparatus as a ram device to kill or incapacitate prey in the sand below. The ray then apidly sucks in the stunned prey along with sand, sorts the edible matter from the sand within the buccal cavity, and releases the sand via the gill slits. Time from ramming the sand to inititation of sifting it is only about 300msec, making this one of the faster behaviours in a fish. Dean & Motta 2004 Zoology (Jena) 107 (3): 171.

NOTE electric rays are found in the Family Narcinidae, from the G. "narc", meaning numbness

Electric ray Narcine brasiliensis 0.3X
INSET: an individual in the process of ramming its
buccal apparatus into the sediment to capture a worm

 

 
 

Benthic invertebrate-eaters: eaters of brittle stars

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a brittle star on a sponge taken from a video

"Brittle stars would seem to be quite vulnerable sitting on sponges and gorgonians as they do. I guess fishes are their main predators. Can you make out this brittle star hanging out on a fire coral? Prabably quite a safe place to be but, ouch, get out the painkillers!" - Turks & Caicos 2005

NOTE possibly a sponge brittle star Ophiothrix sp.

 
 

photograph of ophiuroid on yellow sponge
Although ophiuroids, such as brittle stars and basket stars, are fairly common around Caribbean coral reefs, studies have shown that they tend to be even more abundant in areas photograph of basket star on a gorgonianwhere predatory reef fishes such as wrasses are scarce or absent. Aronson 1998 Mar Ecol Progr Ser 172: 53.

 

Brittle stars Ophiocoma sp.
make perfect fits within protective recesses of
their host sponge 0.6X

 

During daytime a basket star
Astrophyton muricatum wraps
itself into a protective cocoon
within a gorgonian 0.5X

 
 

photograph of hogfish Lachnolaimus maximus
The fact is that most ophiuroids are not very nutritious. Their arms are mostly solid, consisting of plates of calcium carbonate, and there is little soft tissue even in the central discs. Only a few wrasses, including hogfishes, yellowheads, and slippery dicks, seem to include ophiuroids in even small portion in photograph of brittle star Ophiothrix suensoni courtesy Anne Dupont, Floridatheir diets.


Hogfishes Lachnolaimus maximus are
known to include ophiuroids in their
diets along with crabs and snails 0.33X

Sponge brittle-star Ophiothrix
suensonii
illustrating a lack of
"meatiness" 1.5X. Photograph
courtesy Anne Dupont, Florida

  Spanish hogfishes Bodianus rufus and yellowhead wrasses eat sea urchins, crabs, and snails, as well as brittle stars.
 
photo collage of yellowhead wrasse and Spanish hogfish
  Although the fishes in this section are shown as eating sea urchins and ophiuroids, most include many other species of benthic invertebrates in their diets. An example of this is shown here for slippery dicks Halichoeres bivittatus whose diets comprise about 25% echinoderms and 50% other bottom-dwelling invertebrates. Data from Randall 1967 Stud Trop Oceanogr 5: 665.
 
drawing showing percentage composition of a yellowhead wrasse's diet of benthic invertebrates
 
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