Herbivory: Difference between revisions

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Herbivorous fish focus feeding on enriched macrophytes. Shallower reefs have more herbivorous fishes and increased grazing rates as compared to deeper parts of the ocean.
Herbivorous fish focus feeding on enriched macrophytes. Shallower reefs have more herbivorous fishes and increased grazing rates as compared to deeper parts of the ocean.
Some herbivorous fish prey directly on corals. Parrotfish are an example of fish that prey directly on coral. <ref name="Burk" />  
Some herbivorous fish prey directly on corals. Parrotfish are an example of fish that prey directly on coral. <ref name="Burk" />  
[[File:Doofus.jpg|frame|none|500px|Blue Parrotfish fishindex.blogspot.com]][[File:Herbivory9REAL_(1).jpg|frame|center|500px|Pharyngeal teeth micro.cornell.edu]]
[[File:Doofus.jpg|frame|center|500px|Blue Parrotfish fishindex.blogspot.com]]
Typically, herbivorous feed on red, green, and brown macro algae<ref name="Corn" /> They do not have teeth in their jaws, rather pharyngeal teeth positioned farther back in their mouth/ throat region.  
Typically, herbivorous feed on red, green, and brown macro algae<ref name="Corn" /> They do not have teeth in their jaws, rather pharyngeal teeth positioned farther back in their mouth/ throat region.  
 
[[File:Herbivory9REAL_(1).jpg|frame|center|500px|Pharyngeal teeth micro.cornell.edu]]
*Digestion- must break down complex polysaccharide cell wall
*Digestion- must break down complex polysaccharide cell wall
*Mechanical-stomach grinds the algal cells
*Mechanical-stomach grinds the algal cells

Revision as of 20:47, 14 April 2014

Herbivory

Three Types of Herbivorous Fishes [1]

Reef fishes that are herbivores are typically invertebrates [2]. There are three types of herbivorous fishes. These include territorial grazers, roving grazers, and scrapers. Territorial grazers are site-attached fish that actively defend their territories against other herbivores. One example of a territorial grazer is a damselfish.

Longfin Damselfish-Juvenile www.mediahex.com

Roving Grazers are mobile herbivore fish that move around reefs in large schools. These fish feed on macro algae and epilithic algae, or algae that is found on stone. The last type of herbivorous fish are scrapers. Scrapers are highly mobile fish that consume epilithic algae and remove sediment by scraping limestone surface of reefs. A few examples of herbivorous fish include: surgeonfish, butterflyfish, angelfish[2]

Feeding Habits of Herbivore Fish/How Food is Digested[2]

Herbivorous fish focus feeding on enriched macrophytes. Shallower reefs have more herbivorous fishes and increased grazing rates as compared to deeper parts of the ocean. Some herbivorous fish prey directly on corals. Parrotfish are an example of fish that prey directly on coral. [3]

Blue Parrotfish fishindex.blogspot.com

Typically, herbivorous feed on red, green, and brown macro algae[2] They do not have teeth in their jaws, rather pharyngeal teeth positioned farther back in their mouth/ throat region.

Pharyngeal teeth micro.cornell.edu
  • Digestion- must break down complex polysaccharide cell wall
  • Mechanical-stomach grinds the algal cells
  • Chemical-use acid lysis in the stomach
  • Enzymatic digestion-enzymes produced by gastrointestinal tract can further break down algal cells/ intestinal microbes are key

Benefits of Herbivore Fishes to Stability of Coral Reefs

  • Help maintain coral dominated states
  • Limit growth of macro algae that compete with coral space
  • A decrease in herbivore fish can be linked to increase in macro algae and coral reef mortality (macroalgae and phytoplankton most significant primary producer in system)
  • Facilitate maintenance of reefs in coral dominated states[1]
  • Strong top down control of macroalgae
  • Elimination of herbivore fish can negatively impact survival, growth, and recruitment of corals and increase in prevalence of coral diseases
  • Alteration in consumer pressure will reduce coral reef resilience and increase probability that climate change, ocean acidification, etc. will drive reefs to state like algal domination
  • Turf algae and upright macroalgae increase are due to herbivore exclusion[3]
  • One of the most well known cases of overgrowth occurred in the Caribbean after a previously unseen disease virtually killed off the herbivorous sea urchin Diadema antillarum[2]
    • Caused collapse of Caribbean reefs in this area
    • Macroalgae became dominant
    • Decrease in diversity

References

  1. 1.0 1.1 Loïc M. Thibaut, Sean R. Connolly, and Hugh P. A. Sweatman 2012. Diversity and stability of herbivorous fishes on coral reefs. **Ecology 93:891–901. http://dx.doi.org/10.1890/11-1753.1
  2. 2.0 2.1 2.2 2.3 2.4 Cornell University: College of Agriculture and Life Sciences, "Herbivory in Fish." Last modified 2014. Accessed February 23, 2014. http://micro.cornell.edu/research/epulopiscium/herbivory-fish.
  3. 3.0 3.1 Burkepile, Deron E. , and Mark E. Hay. "Nutrient versus herbivore control of macroalgal community development and coral growth on a Caribbean reef."Inter-Research Marine Ecology Progress Series. (2009). http://www.int-res.com/abstracts/meps/v389/p71-84/ (accessed February 23, 2014).
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