Anatomy of finfish and shellfish

Unit – 3 Study of oral region and Associated structures

3.4. Gill Rakers
Besides protecting the tender gill filaments form abrasion (a rubbing off or scrap) by ingested materially that are coarse in texture, gill rakers are specialization in relation to food and feeding habits. They are very stubby (short and thick) and unornamented in most omnivores for example sunfish (Lepomis cynellus).
In many plankton feeders, the gill rakers are elongated, numerous are variously lamellate or ornamented to increase efficiency of filtering. Simple but very numerous rakers are possessed by gizzard shads (Dorosoma) and paddlefish (polyodon) Ornamentation of gill rackers are of taxonomic value. In pleuronectdae the gill rakers resembles feather having a main axis with lateral processes these lateral processes are branched. The adjacent gill rakers overlap to form a very fine sieve.