Kype Kype 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. 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. The kype functions as a secondary sexual characteristic and influences the formation of dominance hierarchies at the spawning grounds. The
Ostorhinchus doederleini the male is solitary while brooding. He may incubate several broods during one breeding season, which is a few months long, depending on location. One mass contains about 10,000 eggs. One brood is incubated for 5 to 17 days. The length of time depends on water temperature. A larger male will generally incubate more eggs at a time. Also, males' mouths get larger during the breeding season, expanding significantly. The lower jaw becomes more depressed in shape. The male quite often eats his eggs. In one study, 361 egg masses were brooded by males, and they had eaten 47 of