World Library  
Flag as Inappropriate
Email this Article

Gill raker

Article Id: WHEBN0008188359
Reproduction Date:

Title: Gill raker  
Author: World Heritage Encyclopedia
Language: English
Subject: Deep sea fish, Aquatic predation, Gill, Diversity of fish, Forage fish
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Gill raker

Top left: Gill-rakers attached to the branchial arch, showing the projecting rows of hooks (x50)
Top right: Hooks attached to the gill-raker, (x180)
Bottom: Gill-rakers in cross section, showing angle at which hooks project from their point of attachment (water flow is downwards)

Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the bony part of the gill. Rakers are usually present in two rows, projecting from both the anterior and posterior side of each gill arch. Rakers are widely varied in number, spacing, and form. By preventing food particles from exiting the spaces between the gill arches, they enable the retention of food particles in filter feeders.[1]

The structure and spacing of gill rakers in fish determines the size of food particles trapped, and correlates with feeding behavior. Fish with densely spaced, elongated, comb-like gill rakers are efficient at filtering tiny prey, whereas carnivores and omnivores often have more widely spaced gill rakers with secondary projections. Because gill raker characters often vary between closely related taxa, they are commonly used in the classification and identification of fish species. Much of the variation in gill raker morphology is thought to be due to adaptation to optimize the consumption of different diets.

In order to prevent the potentially damaging passage of solid material through the gill slits and over the gill filaments, early gill rakers strained large particles from the water and diverted them to the esophagus. Since an appreciable fraction of this material was nutritious, rakers subsequently evolved as food-trapping mechanisms in filter feeders. Gill rakers, when long and closely set, play the same role in suspension feeding fish such as mullet, herring, megamouth, basking and whale sharks, as baleen in the filter-feeding whales.[2]

References

  1. ^ http://203.250.122.194/lecture/anatomy/htmanat2/anat14.htm
  2. ^ Salman, Nadir A.; Al-Mahdawi, Ghaith J. and Hassan; Heba, M.A. (2005). "Gill Rakers Morphometry and Filtering Mechanism in some Marine Teleosts from Red Sea Coasts of Yemen". Egyptian Journal of Aquatic Research 31 (Special Issue): 286–296. Retrieved 2 March 2013. 
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.