While all kypes share the same basic purpose - helping males establish dominance during spawning - they vary significantly between species. Each type of fish has evolved its own unique kype characteristics to suit its specific reproductive strategies and environmental conditions.
Explore the different species below to learn about their distinctive kype features and how they function in the wild.
Atlantic Salmon
Salmo salar
The Atlantic salmon develops one of the most prominent kypes among salmonids. Unlike Pacific salmon species, Atlantic salmon can be iteroparous (capable of spawning multiple times), which affects how their kypes develop over multiple spawning cycles.
Kype Characteristics:
- Forms during migration from salt to freshwater
- Made of fast-growing skeletal needles that differ from regular dentary bone
- In repeat spawners, the kype is partially resorbed after spawning, but basal parts are remodeled into regular dentary bone
- May become progressively larger in subsequent spawning cycles
Brown Trout
Salmo trutta
Brown trout are famous for their larger, more pronounced kypes compared to other trout species. These fish often develop kypes during late fall or early winter spawning periods, with some individuals maintaining their kypes permanently.
Kype Characteristics:
- Typically larger and more pronounced than in other trout species
- Often accompanied by vibrant spawning colors, especially in males
- In large, older specimens, kypes may become permanent and continue to grow with age
- Serves as both a dominance signal and possibly a tool for fighting with rival males
Coho Salmon
Oncorhynchus kisutch
Coho salmon develop strongly hooked kypes during their single spawning event. As semelparous fish (spawning only once before death), their kypes develop rapidly as they make their final journey upstream.
Kype Characteristics:
- Develops quickly during the final spawning migration
- Accompanied by dramatic color changes from silver to deep red sides
- Often more pronounced in larger, older individuals
- Features large canine-like teeth that develop alongside the kype
Rainbow Trout
Oncorhynchus mykiss
Rainbow trout males develop moderate kypes prior to spawning periods. The anadromous form (steelhead) shows particularly dramatic kype development during their spawning migration from the ocean back to freshwater.
Kype Characteristics:
- Moderate in size compared to brown trout or salmon
- Development coincides with intensification of the distinctive pink/red stripe
- More pronounced in steelhead (anadromous rainbow trout) than in resident forms
- Usually resorbed after spawning in most individuals
Chinook Salmon
Oncorhynchus tshawytscha
Chinook salmon (also known as King salmon) show interesting variations in kype development related to alternative reproductive tactics. "Hooknose" males develop larger kypes, while early-maturing "jack" males show less pronounced kype development.
Kype Characteristics:
- Varies significantly between "hooknose" and "jack" male types
- In large "hooknose" males, kypes can be extremely pronounced
- Accompanied by darkening of the body and sometimes a slight hump
- Size correlates with dominance in spawning hierarchies
Bull Trout
Salvelinus confluentus
Bull trout are adfluvial (adults spawn in streams but subadults and adults migrate to lakes for feeding) and develop moderate kypes during spawning. Their kypes tend to be less extreme than those of salmon or brown trout.
Kype Characteristics:
- More subtle than in salmon or brown trout
- Typically accompanied by vibrant red or orange spots during spawning
- Develops mainly in larger, migratory individuals
- Generally resorbed after the spawning season