Nutrition
 
  Nutrition
 
 
Herbivory 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
There are 4 major trophic levels on a reef, with herbivory being considered here. Information on the others, including a 5th category of "Corals: a case study" (corals use all trophic modes), can be accessed via the icons.
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a bicolor damselfish taken from a video

"Seaweeds are all over the reef, but may be overlooked. Not in this bicolor damselfish's garden, though. Lots of bushy growth of algae and lots to patrol. There's also quite a rich growth in this longfin damselfish's garden." - Bonaire 2003, Turneffe Island 2001. Video of longfin damselfish courtesy Andy Stockbridge, Belize

NOTE Stegastes diencaeus

 
 

Herbivory: algivores (seaweed-eaters)

hot buttons for herbivory part of BCCR hot button for seagrass-eaters section of BCCR hot button for phytoplanktivores section of BCCR hot button for algivores section of BCCR

This section of herbivory deals with algivores; information on other types of reef herbivores can be accessed via the icons.

NOTE lit. "seaweed eat" L., referring to animals that specifically eat seaweeds or algae. In BCCR the terms "seaweed" and "algae" are used more or less synonymously, although they are not the same. While all seaweeds are algae, not all algae are seaweeds

 
 

Herbivory: algivores: fishes

hot buttons for algivory part of BCCR hot button for fishes part of algivores section in BCCR hot button for sea-urchin part of algivores in BCCR hot button for crustaceans/chitons/snails part of algivores in BCCR

There are about 600 species of seaweeds in the Caribbean. They are eaten primarily by fishes and sea urchins, but other invertebrates such as chitons, snails, and various crustaceans also take their share. This first section deals with algivorous fishes. Accounts of other algivores on the reef can be accessed via the icons.

 

 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of herbivorous Caribbean reef-fishes taken from a video "Some of the busiest fish on the reef are herbivores. Watch how they pick a bit here and a bit there...seems a common behaviour. Maybe they're fussy and select only the best seaweeds. Or, perhaps their vulnerability to attack is reduced by having short feeding sessions. Or, maybe they have to keep topping up their stomachs because the quality of food is poor, and they need maximum time for digestion." - Cozumel 2005
 
  Examples of Caribbean reef fishes that consume seaweeds are:
 
photograph of striped parrotfishes feeding photograph of 3-spot damselfish photograph of blue tang feeding
3-spot damselfish Stegastes planifrons 0.3X
Initial-phase striped parrotfishes Scarus croicensis grazing on algae 0.15X   Blue tang Acanthurus coeruleus feeding 0.4X
 

Only about one-tenth of all Caribbean reef fishes primarily eat seaweeds or seagrasses, but their constant activity, noisy eating, and visual obviousness during daytime belies this small number. Sierra et al. 2001 Ecology of the marine fishes of Cuba. Smithsonian Inst, Washington.

NOTE if all fishes that eat algae for at least part of their diet are included, then this total rises to about 25%. DeLoach 1999 Reef fish behavior. New World Publ., Inc., Florida

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

"Here's a busy group. Let's see...ocean surgeonfishes, blue tang, juvenile princess parrotfish, terminal-phase striped parrotfish, and what looks to be an initial-stage redband parrotfish. Pity the poor algae. Let's get close to this initial-phase queen parrotfish so we can better hear and see its chomping." - Cayman Brac 2001

NOTE Scarus vetula

 
  Mouths and teeth of fishes can tell a lot about their diets. Study the presentation below and mentally sort out the herbivorous and carnivorous fishes on the basis of expected differences in mouth morphologies, then CLICK HERE to see them correctly sorted.
 
array of mouths of herbivorous and carnivorous fishes to show differences in mouth and teeth morphologies
 
 

photograph of dusky damselfish Stegastes fuscus
Damselfishes cultivate small garden plots which, thanks to the damselfishes' aggressive behaviour in driving away othr herbivorous fishes, may have more biomass of seaweeds within than without.

 

 

 

 

A dusky damselfish Stegastes fuscus
in its rich garden-plot 0.33X

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

"Parrotfishes have hard beak-like jaws, and they're constantly biting at the reef, including hard corals, in their quest for algal foods. Here's a princess parrotfish working away, and over there a terminal-phase queen parrotfish is finding something good to eat." - Bonaire 2003, Turks & Caicos 2003

NOTE Scarus taeniopterus

NOTE Scarus vetula

 
 


The beak-like mouths of parrotfishes "bioerode" hard substrata, but the way this happens differs in different species. In Bonaire, parrotfishes annually remove up to 7kg from every square meter of reef-area bottom. A substratum infested with boring algae is softer and more erodable photograph of initial-phase stoplight parrotfish Sparisoma viride
than a harder surface made up of crustose-coralline algae. Of the 2 species shown here, stoplights tend to be "excavators" and photograph of queen parrotfish Scarus vetuladig more deeply into the substratum; conversely, queen parrotfishes are "scrapers", and tend to remove surface layers. Bruggermann et al. 1996 Mar Ecol Progr Ser 134: 59.

Queen parrotfish Scarus vetula 0.3X

 

Initial-phase stoplight parrotfish
Sparisoma viride
0.25X

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

"Parrotfishes are so busy, swimming and chomping. Often you hear them feeding without even seeing them. They apparently have an auxiliary grinding device in their guts, just to deal with all the roughage. Even some of their turf algal foods are not that nutritious, let alone scrapings from coral." - Cayman Brac 2001

NOTE featured here, stoplight parrotfish Sparisoma viride

 
  graph showing percentage bites of stoplight parrotfishes on different food substrata
Studies on diets of stoplight parrotfishes Sparisoma viride in shallow reef areas in Bonaire reveal that they usually have strong preferences for what they eat. The graph below shows percentage bites by all life stage on each substratum shown, over a 14mo observation period. Bruggemann et al. 1994 Mar Ecol Progr Ser 106: 41.
 
 
seahorse dive leader for Biology of Caribbean Coral Reefs website photograph of a terminal-phase stoplight parrotfish taken from a video

"With all that calcareous roughage it's no wonder that parrotfishes defecate so much. They seem to do it mostly up in the water column, or maybe it's just more noticeable as it rains down on you. It also may be a natural response of getting the muscles moving during a cruise over the reef." - St. Thomas 2006

NOTE featured here, stoplight parrotfish Sparisoma viride

 
  photograph of terminal-phase stoplight parrotfish Sparisoma vetulaphotoDrawing of stoplight parrotfish defecating
How much does a parrotfish eat in a day? Well, the one featured here weighs 140g and will feed more or less continuously throughout the day, starting at dawn and ending at dusk. Overall, it will take in each day a total of about 110g of algae mixed with scrapings, representing about 80% of its body mass. The fish will defecate 100g of material in a day, representing about 90% of the amount eaten. The feces are made up of much white calcium from coral skeletons, seaweeds, and bottom debris eaten as food.
 
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