Kype

The kype is the hook on the lower jaw which some salmonids develop before the breeding season.

A kype is a hook-like secondary sex characteristic which develops at the distal tip of the lower jaw in some male salmonids prior to the spawning season.[1][2] The structure usually develops in the weeks prior to, and during, migration to the spawning grounds. In addition to the development of the kype, a large depression forms in the two halves of the premaxilla in the upper jaw, allowing the kype to fit into the premaxilla when the mouth is closed.[3]

The kype functions as a secondary sexual characteristic and influences the formation of dominance hierarchies at the spawning grounds. The size of the kype is believed to determine male spawning frequency.

  1. ^ "Kype". FishBase. Retrieved April 26, 2016.
  2. ^ Cite error: The named reference Jarvi was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Witten was invoked but never defined (see the help page).