Nutrition
 
column spacer Nutrition
 
 
Carnivory hot buttons for nutrition part of BCCR hot button for primary productivity part of BCCR hot button for carnivory part of BCCR hot button for Corals: a case study part of BCCR hot button for herbivory part of BCCR hot button for detrivory/bacterivory part of BCCR
This part of nutrition deals with carnivory, that is, with coral-reef organisms that eat animals. Other topics relating to nutrition of coral reefs can be accessed via the icons.
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of permits swimming, taken from a video

"Lots of reef animals are trying to eat one another, but it's rare to see an actual killing. These permits are on their best behaviour while we're here, but you can be sure they'll be back to hunting for shellfish when we leave." - Turneffe Island, Belize 2002. Video courtesy Andy Stockbridge, Belize.

NOTE Trachinotus falcatus

 
  Many reef animals are carnivores, but their dietary preferences can be quite generalised. For example, Atlantic spadefishes are known to eat sponges, zoanthids, feather-duster worms, and a variety of other prey...
 

photograph of Atlantic spadefish Chaetodipterus faber, courtesy Anne Dupont, Floridaphoto collage of prey of Atlantic spadefishes

 

 

 

 

 



Atlantic spadefish Chaetodipterus faber 0.15X

 
 

Carnivory: zooplanktivores (zooplankton-eaters)

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
The treatment of carnivory in BCCR is by taxonomic group being eaten. Thus, zooplankton-eaters includes animals that eat zooplankton. Other topics relating to carnivory can be accessed via the icons.
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of chromises swimming over the reef taken from a video

"Lots of activity here. If you watch carefully, you will see that the brown chromises are eating things from the plankton...perhaps larvae or small planktonic crustaceans." - Little Cayman

NOTE Chromis multilineata

 
  Many reef invertebrates eat zooplankton, including corals...
 
photo collage of coral polyps Montastrea cavernosa with the zooplanktonic food of these polyps
 
  graph showing relationship between colony height and number of bands in fire coral Millepora complanataFire corals Millepora spp. also eat zooplankton, stinging them to death with highly toxic nematocysts. A study in Barbados shows that vertical growth in drapery-like colonies of Millepora complanata is commonly in bands (see photograph below), with the number of bands being directly related to colony height (see graph). Just like growth rings on a tree, each band appears to be seasonal. So, by counting bands, a colony can be aged. Lewis 1991 Coral Reefs 9: 209.
 
drawing of vertical section of colony of fire coral Millepora complanata showing growth bands colony of fire coral Millepora complanata without growth bands
Vertical section showing bandings Six growth bands are visible on this colony of Millepora complanata suggesting an age of 6yr No growth bands are visible in this colour photograph. Perhaps the author's black & white film emphasises the differences in shading
 


 
photo collage of various benthic-invertebrate predators of zooplankton
 

photograph of Caribbean hydroid Halocordyle distichaphotograph of bryozoan Reteporellina evelinaeMany small reef invertebrates such as hydroids and bryozoans eat zooplankton...

 

Christmas-tree hydroid
Halocordyle disticha 0.7X


White-fan bryozoan Reteporellina
evelinae
and other bryozoans feed
on small components of the
plankton,including protists
and invertebrate larvae 2X

 

photograph of a Beroe-type ctenophore
...as do various pelagic gelatinous invertebrates such as ctenophores and jellyfishes. Ctenophores capture small planktonic prey such as crustaceans and larval fishes on long fishing tentacles. The tentacles have microscopic devices known as colloblasts that on photgraph of stimulation discharge a sticky thread that sticks to and tangles the prey, and allows it to be drawn in to the mouth.

NOTE a small phylum of mostly planktonic animals known as comb-jellies or sea marbles

The Beroe-type ctenophore featured here
actually lacks tentacles, but is able to engulf
and eat other ctenophores 1X

This jellyfish from the Gulf of Mexico
employs toxic nematocysts to catch small
zooplankters from the plankton 0.25X

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of sergeant-major taken from a video

"Numerous pomacentrid and other fishes, including this sergeant-major, hang out on the reef crest looking for planktonic food. Let's watch this sergeant-major and see what it does. Yes, it does a lot of swimming...and more swimming...and more swimming. But, wait! Watch its mouth. It's eating things from the plankton...probably small crustaceans or invertebrate larvae." - Little Cayman 2003

NOTE Abudefdus saxatilis

 
 

photograph of pomacentrid fishes on reef crest
Some 11% of Caribbean fishes, including the pomacentrids shown here, primarily eat zooplankton. Sierra et al. 2001 Ecology of the marine fishes of Cuba. Smiths Inst Press, Washington.

 

 

 

 

Species in the Family Pomacentridae, like these blue chromises
Chromis cyanea
and brown chromises C. multilineata, form a
"wall of mouths" on the reef crest during daytime 0.3X

  Mouths of planktivorous fishes, such as pomacentrids Chromis spp. are usually small, upturned, and protusible. On close approach to a prey the jaws are shot forward and the prey engulfed. Apparently, the capture of fast-moving zooplankters relies less on suction than on the speed of jaw protusion; for slow-moving prey, jaw protusion is lessened and suction increased by special buccal expansion. The images below show the engulfing process as used to catch a fast-reacting copepod:
 
sequence showing a blue chromis engulfing a copepod using jaw protusion 1 sequence showing a blue chromis engulfing a copepod using jaw protusion 2 sequence showing a blue chromis engulfing a copepod using jaw protusion 3
 
  The further off the reef that planktivorous fishes venture in search of food, the better adapted they are to swim fast and hold station in face of strong currents. Hobson 1991 p.69 In, The ecology of fishes on coral reefs (ed., P. Sale) Academic Press, San Diego.
 
photographs comparing shapes and agilities of 2 reef fishes
 

photograph of initial-stage creole wrassesCreole wrasses eat a variety of zooplankters, including gelatinous prey such as jellyfishes and ctenophores. The abundance of wrasses is usually reflective of the amount of plankton productivity in an area.

 

 

 

Shoal of initial-phase creole
wrasses Clepticus parrae 0.15X

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of razorfish taken from a video

"Who's this buzzing about? Oh! It's a razorfish, and it looks like it just caught and ate something from the plankton...probably a copepod." - St. John 2007

NOTE rosy razorfish Hemipteronotus martinicensis

 
 

In contrast to zooplanktivorous fishes that swim openly in the plankton to feed, some species, as for example, bottom-dwelling blennies, lie in wait for their prey to happen by. A study on several co-occurring blenny species in Carrie Bow Cay, Belize shows that there tends to be spatial separation of species with similar feeding habits, such that competition for food is minimised. For example, Acanthemblemaria spinosa and A. aspersa both feed on copopods, but the former does so from a position higher on the reef than the latter. Thus, A. spinosa concentrates mainly on planktonic copepods, while A. aspersa concentrates mainly on bottom-crawling/swimming copepods. In field experiments where a selection of benthic and pelagic copepods is offered to the 2 species, preferences in each case are for the copepod-species that each blenny is accustomed to eating in its natural habitat. Clarke 1999 Bull Mar Sci 65: 185.

NOTE this sounds as if the blennies' choices are absolute, with no overlap, but they are not so fussy. The actual preference data from field animals show that spineyhead blennies (the higher reef-dwellers) eat about 4-fold more planktonic copepods than benthic ones, while roughhead blennies (the lower reef-dwellers) eat about 50-fold more benthic copopods than planktonic ones

 
photo/diagram showing prey allocation in coral-inhabiting blennies Acanthemblemaria
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of roughhead blenny taken from a video

"In contrast with pomacentrids, which chase down their zooplankton prey, other fishes feed from positions of ambush. This roughhead blenny looks around with its big eye, then eats something that swims by...maybe a copepod crustacean." - Turneffe Island 2002. Video courtesy Andy Stockbridge, Belize.

NOTE Acanthemblemaria aspera

 
  If you missed the details of what happened in the video, here are the single images, starting from the fish spotting something in the plankton, to it attacking, engulfing, and resuming its place. The sequence ends with a mouth-extending swallow (image 3rd Right bottom row).
 
photograph 1 in a series showing a roughhead blenny Acanthemblemaria aspersa feeding on something in the plankton photograph 2 in a series showing a roughhead blenny Acanthemblemaria aspersa feeding on something in the plankton photograph 3 in a series showing a roughhead blenny Acanthemblemaria aspersa feeding on something in the plankton photograph 4 in a series showing a roughhead blenny Acanthemblemaria aspersa feeding on something in the plankton
photograph 5 in a series showing a roughhead blenny Acanthemblemaria aspersa feeding on something in the plankton photograph 6 in a series showing a roughhead blenny Acanthemblemaria aspersa feeding on something in the plankton photograph 7 in a series showing a roughhead blenny Acanthemblemaria aspersa feeding on something in the plankton photograph 8 in a series showing a roughhead blenny Acanthemblemaria aspersa feeding on something in the plankton
 
 
seahorse dive leader for Biology of Caribbean Coral Reef website photograph of school of mysid shrimps taken from a video

"As we move through the reef we often see schools of zooplankton like this one. It's hard to tell what kind they are, but mysid shrimps would be my guess. Here's another batch in front of a conch. Are they sheltering in the shade, do you think? I wonder why they aren't gobbled up by fishes? Perhaps they have great escape speed or are bad tasting in some way." - Cayman Brac 2003

NOTE Mysis sp.

 
  photograph of mysid shrimps in a swarm
Tracking-type studies on mysid shrimps in Jamaica show that a swarm will disperse in the evening and re-form in the same location in the morning. About three-quarters of the individuals in a swarm will show fidelity to their previous-day's location, while the remainder will move away to join up with nearby swarms. Twining et al. 2000 Limnol Oceanogr 45: 1845.
  Just as is thought to happen with schooling fishes, forming up in swarms provides protection for mysid shrimps by creating a visually confusing mass to a potential predator. Attack this one, or that one...or the one over there? Oh, forget it! The theory is made clear in this cartoon series:
 
 
cartoon 1 in a series explaining swarm-formation and maintenance in mysid shrimps cartoon 1 in a series explaining swarm-formation and maintenance in mysid shrimps
cartoon 1 in a series explaining swarm-formation and maintenance in mysid shrimps cartoon 2 in a series explaining swarm-formation and maintenance in mysid shrimps
cartoon 3 in a series explaining swarm-formation and maintenance in mysid shrimps cartoon 4 in a series explaining swarm-formation and maintenance in mysid shrimps
cartoon 5 in a series explaining swarm-formation and maintenance in mysid shrimps cartoon 6 in a series explaining swarm-formation and maintenance in mysid shrimps
cartoon 7 in a series explaining swarm-formation and maintenance in mysid shrimps cartoon 8 in a series explaining swarm-formation and maintenance in mysid shrimps
 
 

While it may not be clear how the mysids identify their daytime swarming locations, the function of the aggregating or schooling behaviour is similar to that of schooling in fishes. Additionally, the escape responses of mysid shrimps are among the fastest known for any animal. Note in the simulation below that a threatening forward move by the bluehead wrasse elicits almost instantaneous dispersive moves away by the swarm-members.

 
photo collage 1 showing response of mysid shrimps to attack by a bluehead wrasse photo collage 1 showing response of mysid shrimps to attack by a bluehead wrasse photo collage 1 showing response of mysid shrimps to attack by a bluehead wrasse
 
  RETURN TO TOP