Other Techniques

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Other Techniques

Filter Feeding

Filter feeding is a feeding method observed among some types of fish in Caribbean reefs. Filter feeders filter dissolved and suspended organic matter from the water by forcing water to flow across specialized filtration structures. The most common food source for filter feeding fish is plankton or other small organisms. In fish, the anatomical structures used to filter out plankton are most often gill rakers.[1].


Herring are one example of a fish that uses filter feeding, although they use it as one of two methods of feeding (the other is particulate-feeding) [2]. When filter feeding, herrings swim through the water with an open or snapping mouth, allowing water to flow through the oral cavity and out gill openings, using long and thin gill rakers to sift out the small crustaceans and plankton present in the water column (Marshall Islands). The sieve effect of the gill rakers causes food particles to concentrate in the oral cavity, after which they are ingested [3].


    • Example: Manta Rays
      • Ram filter-feeders:swims through a plankton bloom with their mouth open, continuously filtering food particles [4]
      • unfurl horn-like cephalic fins (picture) from either side of mouth to act as a funnel [5]
      • expand flattened body and propel themselves through water with mouth open - water flows through mouth and out over 5 pairs of gill slits that line its throat [5]
      • any plankton larger than grain of sand is filtered out of water and trapped by feathered gill plates [5]
      • thought to use cross-flow filtration:
        • water flows mostly parallel to filter surface, only deviating slightly to dip across filter surface and siphon out the gills [6]
        • Food particles that have more momentum carry go straight to the back of the mouth, forming a concentrated ball of food [6]
        • "Cross-flow filtration works as a self-cleaning mechanism that pushes any particles that collect on the filter back toward the esophagus to be swallowed, no mucus necessary. This mechanism of filtration alleviates clogging of the filter, allowing the animal to feed for longer periods without closing its mouth to process the food particles."[7]
      • various swimming techniques while filter feeding - barrel rolling, bottom feeding, surface feeding, feeding chains, cyclone feeding [5]
    • Example: Whale Shark
      • Also ram feeding - "rams" water and food (plankton) through the filtering pads covering the entrance to their throat [8]

Detritivores

    • Consume dead organic material and return nutrients to the sediment. [9]
    • Definition of dead organic material: animal and plant remains, waste products, and the bacteria/microorganisms associated with waste products [10]
    • At least 3 reef fish families have been identified as feeding heavily on detritus in what is called the "epilithic algal matrix": Surgeonfishes, damselfishes, and blennies [10]
    • Hard Substrate Detritivores (most members of the Ctenochaetus genus) [10]
      • feeding technique: press jaw against substrate and then throw lower jaw upward[10]
      • effectively brushes particulate matter off of rock and dead corals, and also out of turf algae[10]
    • Sediment Detritivores
      • feeding technique: eat mouthfuls of sand and associated debris[10]
      • Example: orange-shoulder surgeonfish[10]
      • Example: Spotted Surgeonfish - Feeds by whisking comb-like teeth over the bottom as it closes its mouth [11]
    • Algal Detritivores
      • Technique: scape algae off of hard surface, along with associated filamentous algae, diatoms, detritus, and sand (eat some algae, but primary source of nutrition is detritus within algae) [12]
      • Example: Combtooth Blennies [12]
    • Mucus-feeders: "consume only coral mucus without removing any other live coral tissue or underlying skeleton" [13]
      • coral mucus contains energy-rich wax esters, fatty acids, and triglycerides, which provide valuable source of energy for many fish [10][13][14]
      • Corals produce a lot of mucus, producing 51-480 mg m^-2 d^-1 [14]
      • Study by Bensen and Muscatine (1974) [15]
        • When coral mucus was artificially dispersed, fish assembled and avidly ingested it
        • Conclusion: coral mucus is an important food source for reef inhabitants and could be an energy source linking the coral producer and small fish consumers in reef communities
      • Example: Ornate Butterfly Fish has been shown to consume large quantities of coral when feeding [10][16]
    • Scavengers
      • Carrion not common on coral reefs [17]
      • One study found that all carrion left on reef was consumed within 24 hours at very rapid rates - indicates that scavenged biomass is tightly recycled within the reef fish community[17]
      • Example: Tiger Shark [18]

Notes

  1. http://www.coralscience.org/main/articles/aquaculture-a-husbandry-4/filter-feeders
  2. Gibson, R.N., and A. Ezzi. "Effect of Particle Concentration on Filter- and Particulate-feeding in the Herring Clupea Harengus." Marine Biology 88, no. 2 (1985): 109-16.
  3. Sanderson, S. L., Cheer, A. Y., Goodrich, J. S., Graziano, J. D., & Callan, W. T. (2001). Crossflow filtration in suspension-feeding fishes. Nature, 412(6845), 439-41. doi:http://dx.doi.org/10.1038/35086574
  4. Paig-Tran, E. (2012). Filtration at the mega-scale: Exploring the filter morphology and filtration mechanisms in the cartilaginous fishes (Order No. 3552837). Available from ProQuest Dissertations & Theses Full Text; ProQuest Dissertations & Theses Global. (1312511009). Retrieved from http://search.proquest.com/docview/1312511009?accountid=14244
  5. 5.0 5.1 5.2 5.3 http://www.mantatrust.org/about-mantas/feeding-frenzy/
  6. 6.0 6.1 Brainerd, E. L. (2001). Caught in the crossflow. Nature, 412(6845), 387-8. doi:http://dx.doi.org/10.1038/35086666
  7. Paig-Tran, Misty. "Secrets of Filter-Feeding Sharks and Rays." College of the Environment at the University of Washington. January 1, 2013. http://depts.washington.edu/fhl/enews/winter2013/misty.html.
  8. http://www.cas.usf.edu/news/s/89
  9. http://education.nationalgeographic.com/education/media/coral-reef-food-web/?ar_a=1
  10. 10.0 10.1 10.2 10.3 10.4 10.5 10.6 10.7 10.8 http://www.fishchannel.com/fish-health/saltwater-conditions/marine-fish-feeding-guilds.aspx
  11. http://www.fishbase.org/summary/6015
  12. 12.0 12.1 http://www.tfhmagazine.com/details/articles/ber-algae-eaters-the-lawnmower-blennies-full-article.htm
  13. 13.0 13.1 Rotjan, Randi D. "Impact of Coral Predators on Tropical Reefs." Marine Ecology Progress Series 367 (2008): 73-91. Cite error: Invalid <ref> tag; name "Rotjan" defined multiple times with different content
  14. 14.0 14.1 Coffroth 1984, http://www.nsm.buffalo.edu/Bio/burr/Publications/4%20Coffroth1984.pdf
  15. Benson and Muscatine 1974, http://aslo.net/lo/toc/vol_19/issue_5/0810.pdf
  16. Cole, Andrew J., Morgan S. Pratchett, and Geoffrey P. Jones. "Diversity and Functional Importance of Coral-feeding Fishes on Tropical Coral Reefs." Fish and Fisheries 9 (2008): 1-22.
  17. 17.0 17.1 Rassweiler, Andrew, and Thomas Rassweiler. "Does Rapid Scavenging Hide Non-predation Mortality in Coral-reef Communities?" Marine and Freshwater Research 62 (2011): 510-15.
  18. http://marinebio.org/species.asp?id=37
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