Gill raker

Rakers are usually present in two rows, projecting from both the anterior and posterior side of each gill arch.

[1] The structure and spacing of gill rakers in fish determines the size of food particles trapped, and correlates with feeding behavior.

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.

Since an appreciable fraction of this material was nutritious, rakers subsequently evolved as food-trapping mechanisms in filter feeders.