Nutrition
 
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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 gorgonivores, that is, with coral-reef organisms that eat gorgonians. Other topics relating to carnivory can be accessed via the icons.
 
 

Carnivory: gorgonivores (eaters of gorgonians)

Major predators of gorgonians include snails, worms, and fishes.

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of flamingo-tongue shell in gorgonian taken from a video

"We often see snails and worms sitting on gorgonians, perhaps thinking they're just resting... and maybe they are, but they may also be lunching on their hosts." - Little Cayman 2003

NOTE Cyphoma gibbosum

 
 

photograph of flamingo-tongue shell Cyphoma gibbosum eating a sea-rod gorgonianFlamingo-tongue shell Cyphoma gibbosum eats a gorgonian
Flamingo-tongue shells eat the polyps and flesh of gorgonians, and are often found in male-female pairs and in colorful aggregations.

Flamingo-tongue shell Cyphoma gibbosum
scrapes living tissue from a warty sea-
rod gorgonian Eunicea sp. 1X

 

Further consumption will eventually expose
a skeletal rod composed of hard protein,
often calcified, known as gorgonin 1.5X

  photographs of damage caused to gorgonians by feeding activity of flamingo-tongue shells Cyphoma gibbosum, with invasion of algaeShallow wounds to a gorgonian caused by flamingo-tongues and other predators can heal in a few days, but exposure of the skeletal rod and associated loss of protective chemical secretions from the tissues may lead to permanent fouling by blue-green algae and seaweeds. Ruesink & Harvell 1990 Mar Ecol Progr Ser 65: 265; Gerhart 1990 Mar Ecol Progr Ser 62: 103.
 

Sightings of flamingo-tongue shells Cyphoma gibbosum feeding on gorgonians are fairly infrequent on most Caribbean reefs, but on Mona Island, Puerto Rico researchers from the University of Puerto Rico describe large, localised outbreaks on many gorgonian species beginning in 2008. Most popular among the several gorgonian species available is the common sea fan Gorgonia ventalina, with some colonies hosting a hundred or more feeding snails (see photographs below). Under such intense predation a colony’s live tissue may be completely denuded and the proteinaceous axial skeleton fouled by blue-green algae and seaweeds, leading to death. Scharer & Nemeth 2010 Coral Reefs 29: 533.

NOTE all species in the area of Mona Island are affected, including Eunicia sp., Plexaura flexuosa, Pseudoplexaura sp., Pseudopterogorgia americana, Pterogorgia sp., and Iciligorgia schrammi, but the most widely affected species is the common sea fan Gorgonia ventalina

 
photographs of an outbreak of predatory snail Cyphoma gibberosa on gorgonians in Mona Island, Puerto Rico
  Sea fan Gorgonia ventalina being
eaten by snails Cyphoma gibbosum

Sea fan Iciligorgia schrammi partially consumed by C. gibbosum

Close view of sea-rod gorgonian Pseudoplexora sp. being eaten 0.6X  
 
 

photographs of bristleworms Hermodice carunculata eating the stalks of gorgonians
Bristleworms/bearded fireworms eat a variety of cnidarians including zoanthids, sea anemones, and hydrocorals, but they especially favour gorgonians. Even the axial skeleton of a gorgonian, if not too large in diameter, is eaten aong with the flesh and spicules. After a meal the bristleworm's gut is full of nematocysts, both intact and discharged, and also zooxanthellae along with spicules and other tissues. Marsden 1962 Nature 193: 598.

NOTE small calcareous inclusions
that function in support and
possibly protections

 

photographs of preferred and less-preferred gorgonian prey of bristleworms Hermodice carunculataStudies in Puerto Rico show that the bearded fireworm Hermodice carunculata preferentially eats the gorgonian Briareum asbestinum over other species such as Plexaura flexuosa and Pseudoplexaura sp. The worm can sense its prey from some distance and, in preference tests, will crawl to it directly, even passing by the other gorgonian species. The worm's preference for Briareum appears to relate more to its nutritional value than to any lesser content of spicules or defensive chemicals that it may have. Vreeland & Lasker 1989 J Exp Mar Biol Ecol 129: 265.

NOTE in comparison, researchers in Barbados report that this worm mostly feeds on zoanthids Palythoa mammillosa and finger corals Porites spp. This indicates both that Hermodice’s preferences are quite catholic, and that it readily eats quite toxic prey (i.e., Palythoa). Ott & Lewis 1972 Can J Zool 50: 1651.

 
  Let's hear from the fireworm about its feeding preferences:
 
cartoon 1 in a series showing a flamingo-tongue shell interviewing a bristleworm about its feeding habits cartoon 1 in a series showing a flamingo-tongue shell interviewing a bristleworm about its feeding habits cartoon 1 in a series showing a flamingo-tongue shell interviewing a bristleworm about its feeding habits
cartoon 1 in a series showing a flamingo-tongue shell interviewing a bristleworm about its feeding habits cartoon 1 in a series showing a flamingo-tongue shell interviewing a bristleworm about its feeding habits cartoon 1 in a series showing a flamingo-tongue shell interviewing a bristleworm about its feeding habits
cartoon 1 in a series showing a flamingo-tongue shell interviewing a bristleworm about its feeding habits cartoon 1 in a series showing a flamingo-tongue shell interviewing a bristleworm about its feeding habits cartoon 1 in a series showing a flamingo-tongue shell interviewing a bristleworm about its feeding habits
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs Website photograph of blue tang apparently eating a gorgonian polyp

"Several kinds of fishes eat cnidarian polyps. Here we've caught a blue tang in the act of carnivory. Not its usual food, but perhaps its fed up with eating turf algae." - Little Cayman 2001

NOTE Acanthurus coeruleus

 
  photographs of 4-eye butterflyfishes eating polyps from gorgonians
Butterflyfishes eat gorgonian polyps as well as coral polyps. Studies in the San Blas Islands of Panama indicate that gorgonian colonies may lose up to 400 polyps daily to browsing by 4-eye butterflyfishes. This corresponds roughly to the number of polyps found on a 10cm stalk and represents a significant loss if sustained. Lasker 1985 Mar Ecol Progr Ser 21: 213.
 
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