Misplaced Pages

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 fleshy part of the gill used for gas exchange. 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.

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.

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 herring, mullet, megamouth, basking and whale sharks, as baleen in the filter-feeding whales.

References

1. "Respiratory system". 203.250.122.194.
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" (PDF). Egyptian Journal of Aquatic Research. 31 (Special Issue): 286–296. Archived from the original (PDF) on March 20, 2012. Retrieved 2 March 2013.

v t e Fish
About fish	Diversity Ethnoichthyology Evolution Diseases and parasites Fishing Fisheries Environmental impact of fishing - as food Fear of - FishBase Fish kill Hypoxia in - Ichthyology
Anatomy and physiology	Age determination Anguilliformity Bone dermal intramembranous ossification Cleithrum Chromatophore Fins dorsal fin Gill branchial arch gill raker gill slit pharyngeal arch pharyngeal slit pseudobranch Glossohyal Jaw hyomandibula pharyngeal jaw Leydig's organ Mauthner cell Meristics Operculum papillare Papilla Photophore Root effect Shark cartilage Scales ganoine Spiral valve Suckermouth Swim bladder physoclisti physostome Teeth pharyngeal shark Teleost leptins Digital Library
Sensory systems	Ampullae of Lorenzini Barbel Hydrodynamic reception Electroreception and electrogenesis Jamming avoidance response Lateral line Otolith Capacity for pain Schreckstoff Surface wave detection Vision Weberian apparatus
Reproduction	Bubble nest Clasper Egg case Development Ichthyoplankton Juvenile Life history theory Milt Mouthbrooder Polyandry Pregnancy Roe Sequential hermaphroditism Spawning triggers
Locomotion	Fin and flipper locomotion Amphibious Walking Flying Undulatory locomotion Tradeoffs for locomotion in air and water RoboTuna
Other behaviour	Aquatic predation Aquatic respiration Bait ball Bottom feeders Cleaner fish Corallivory Diel vertical migration Electric fish Filter feeders Forage fish Migratory Paedophagy Predatory Salmon run Sardine run Scale eaters Schooling fish Sleep Venomous Intelligence
By habitat	Cave Coastal Coldwater Coral reef Deep-sea Demersal Euryhaline Freshwater Groundfish Pelagic Tropical
Other types	Bait Coarse Diversity Game Genetically modified Hallucinogenic Oily Poisonous Rough Whitefish
Commerce	Farming Carp Catfish Octopus Salmonids Tilapia Wild fisheries Predatory billfish mackerel salmon tuna Forage anchovy herring sardine sprats Demersal cod flatfish pollock
Major groups	Jawless hagfish lampreys Cartilaginous chimaeras sharks rays Bony spiny-finned fleshy-finned
Lists	Aquarium life Blind Fish common names Fish families Glossary of ichthyology Largest Smallest Threatened rays sharks Prehistoric more lists...
Category WikiProject

• Fish anatomy