Jack salmon

Jacks are precotial male salmon that have spent one winter less in the ocean than the youngest females of a given species. Because they are younger, jack salmon are smaller than other age classes of conspecifics. Coho jacks return to spawn the same year they smolted and so are particularly small. Jack coloration can differ from that of older adults. Jacks are able to successfully sneak-spawn in spite of efforts by the female and occasionally the other males.

Lurking jack
A Sockeye Salmon (Oncorhynchus nerka) jack lurking near the tail of an alpha male. In the background, the female they want to spawn with is visible above the alpha male's head.
25Mile Creek Actinopterygii Alaska Chordata Class Actinopterygii Copper River Delta Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Salmonidae Salmoniformes Salmoninae Sockeye Salmon South Central Alaska Subclass Neopterygii Summer Teleost Teleostei United States Vertebrate chordate jack jack salmon precocial male precocious male underwater
Coho Salmon in the act of spawning
Coho Salmon (Oncorhynchus kisutch) in the act of spawning. The male entering the fray from the top is the alpha male changing position after the two sneaker males barged in. The female is to his left. The little male with the spots in the frame on the left is a precotial male a.k.a. jack salmon.
Actinopterygii Alaska Autumn Chordata Class Actinopterygii Coho Salmon Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Power Creek Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon South Central Alaska Subclass Neopterygii Teleost Teleostei United States Vertebrate alpha male biosphere chordate fish behavior in situ jack jack salmon naturalworld nature near Cordova precocial male precocious male spawning spawning act spawning behavior underwater underwaterphoto wild
Coho Salmon jack hiding
A Coho Salmon a.k.a. Silver salmon (Oncorhynchus kisutch) jack or precotial male hiding below an alpha male.
Alaska Alaska wild salmon Autumn Class Actinopterygii Coho Salmon Infraclass Teleostei Oncorhynchus kisutch Pacific salmon Phylum Chordata Power Creek Salmonidae Salmoniformes Salmoninae Sea Sea internal correction lens Seacam underwater housing Silver Salmon South Central Alaska Subclass Neopterygii Teleost United States Vertebrate biosphere in situ jack jack salmon naturalworld nature near Cordova precocial male precocious male underwater underwaterphoto wild wild salmon
Jack salmon interest
A tiny Chinook Salmon a.k.a. King Salmon (Oncorhynchus tshawytscha) jack or precocial male observes a female probing the surface of a rock with her anal fin during redd excavation in Montana Creek near Talkeetna, Alaska.
Actinopterygii Alaska Alaska wild salmon Chinook Salmon Chordata Class Actinopterygii Infraclass Teleostei King Salmon Montana Creek Neopterygii Oncorhynchus tshawytscha Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing South Central Alaska South Central Alaska 1 Subclass Neopterygii Summer Susitna River Tributary Teleost Teleostei United States Vertebrate biosphere chordate fish behavior in situ jack jack salmon naturalworld nature near Talkeetna precocial male precocious male probing spawning behavior underwater underwaterphoto wild wild salmon
Jack salmon escape
A tiny Chinook Salmon a.k.a. King Salmon (Oncorhynchus tshawytscha) jack or precocial male evades being charged at by the alpha male as the female (at right edge of frame) excavates her redd in Montana Creek near Talkeetna, Alaska.
Alaska Alaska wild salmon Chinook Salmon Class Actinopterygii Infraclass Teleostei King Salmon Montana Creek Oncorhynchus tshawytscha Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing South Central Alaska South Central Alaska 1 Subclass Neopterygii Summer Susitna River Tributary Teleost United States Vertebrate biosphere in situ jack jack salmon naturalworld nature near Talkeetna precocial male precocious male underwater underwaterphoto wild wild salmon
Coho Salmon in the act of spawning including a jack
A jack joins a pair of Coho Salmon (Oncorhynchus kisutch) in the act of spawning.
Actinopterygii Alaska wild salmon Autumn Chordata Class Actinopterygii Coho Salmon Dolly Varden Dolly Varden Char Dolly Varden Charr Dolly Varden Charr southern form Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Salvelinus malma Salvelinus malma lordi Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Teleostei Vertebrate biosphere chordate in situ naturalworld underwater wild wild salmon
Chinook Salmon jack
A Chinook Salmon (Oncorhynchus tshawytscha) jack is positioned in a stream next to a redd.
Actinopterygii Alaska wild salmon Chinook Salmon Chordata Class Actinopterygii Infraclass Teleostei King Salmon Neopterygii Oncorhynchus tshawytscha Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Subclass Neopterygii Summer Teleost Teleostei Vertebrate biosphere chordate in situ jack jack salmon naturalworld nature photographed under water precocial male precocious male underwater underwaterphoto wild wild salmon
Two jacks about to join a pair of spawning Coho Salmon spawning pair
Two jacks about to join a pair of spawning Coho Salmon (Oncorhynchus kisutch) spawning pair. Aspect Ratio = 4:5.
Actinopterygii Alaska wild salmon Autumn Chordata Class Actinopterygii Coho Salmon Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Teleostei Vertebrate biosphere chordate in situ jack jack salmon naturalworld nature precocial male precocious male underwater underwaterphoto wild wild salmon
Sockeye Salmon spawning migration
Sockeye Salmon (Oncorhynchus nerka) nearing their spawning grounds in a Copper River Delta, Alaska stream showing variation in breeding colors a.k.a nuptial coloration. The small mostly green-colored salmon with a horizontal red bar on the left side of this image is a jack salmon or precotial male.
Actinopterygii Alaska Chordata Class Actinopterygii Copper River Delta Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Saddlebag Creek Salmonidae Salmoniformes Salmoninae Seacam underwater housing Sockeye Salmon South Central Alaska Subclass Neopterygii Summer Teleost Teleostei United States Vertebrate biosphere breeding colors chordate fish behavior in situ jack jack salmon naturalworld nature nuptial coloration precocial male precocious male spawning migration underwater underwaterphoto wild
Sockeye Salmon spawning
Sockeye Salmon (Oncorhynchus nerka) in the act of spawning. The tiny salmon on the left side of the frame is a precotial male a.k.a. jack salmon. He is also attempting to contribute to the gene pool.
Actinopterygii Chordata Class Actinopterygii Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Sockeye Salmon Subclass Neopterygii Summer Teleost Teleostei Vertebrate biosphere chordate fish behavior in situ jack jack salmon naturalworld nature precocial male precocious male spawning spawning act spawning behavior underwater underwaterphoto wild
Male Sockeye Salmon spawning morphs
A small jack comes alongside a normal sized male Sockeye Salmon (Oncorhynchus nerka).
Actinopterygii Chordata Class Actinopterygii Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Sockeye Salmon Subclass Neopterygii Teleost Teleostei Vertebrate biosphere chordate in situ jack jack salmon naturalworld nature precocial male precocious male underwater underwaterphoto wild
Coho Salmon female with a jack
Female Coho Salmon a.k.a. Silver salmon (Oncorhynchus kisutch) being courted by a jack in an Alaska, USA stream during the autumn.
Alaska wild salmon Autumn Class Actinopterygii Coho Salmon Infraclass Teleostei Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Vertebrate biosphere fish behavior in situ jack jack salmon naturalworld nature precocial male precocious male probing spawning behavior underwater underwaterphoto wild wild salmon
Coho Salmon female with a jack
Coho Salmon (Oncorhynchus kisutch) female with a jack. Aspect ratio = 2:3.
Alaska wild salmon Autumn Class Actinopterygii Coho Salmon Infraclass Teleostei Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Vertebrate biosphere in situ jack jack salmon naturalworld nature precocial male precocious male underwater underwaterphoto wild wild salmon
Coho Salmon after spawning with a jack
Coho Salmon (Oncorhynchus kisutch) after spawning with a jack. Aspect ratio = 2:3.
Alaska wild salmon Autumn Class Actinopterygii Coho Salmon Infraclass Teleostei Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Vertebrate biosphere fish behavior in situ jack jack salmon naturalworld nature precocial male precocious male spawning spawning act spawning behavior underwater underwaterphoto wild wild salmon
Coho Salmon commencing to spawn with a jack
Coho Salmon a.k.a. Silver Silver (Oncorhynchus kisutch) commencing to spawn about to be joined by a jack in an Alaska, USA stream during the autumn.
Alaska wild salmon Autumn Class Actinopterygii Coho Salmon Infraclass Teleostei Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Vertebrate biosphere fish behavior in situ jack jack salmon naturalworld nature precocial male precocious male probing spawning spawning act spawning behavior underwater underwaterphoto wild wild salmon
Coho Salmon female with a jack
Coho Salmon (Oncorhynchus kisutch) female with a jack. Aspect ratio = 2:3.
Alaska wild salmon Autumn Class Actinopterygii Coho Salmon Infraclass Teleostei Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Vertebrate biosphere in situ jack jack salmon naturalworld nature precocial male precocious male underwater underwaterphoto wild wild salmon
Courting Coho Salmon and a Sockeye Salmon jack
A Sockeye Salmon jack emerges from the fracas that often ensues during salmon courtship, in this case another species, Coho Salmon. Aspect Ratio = 1:2.
Alaska wild salmon Autumn Class Actinopterygii Coho Salmon Infraclass Teleostei Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Vertebrate biosphere excavating redd in situ jack jack salmon naturalworld nature precocial male precocious male underwater underwaterphoto wild wild salmon
Coho Salmon jack
Coho Salmon (Oncorhynchus kisutch) jack.
Alaska wild salmon Autumn Class Actinopterygii Coho Salmon Infraclass Teleostei Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Vertebrate biosphere in situ jack jack salmon naturalworld nature precocial male precocious male underwater underwaterphoto wild wild salmon
Coho Salmon female with a jack
Female Coho Salmon a.k.a. Silver salmon (Oncorhynchus kisutch) being courted by a jack in an Alaska, USA stream during the autumn.
Alaska wild salmon Autumn Class Actinopterygii Coho Salmon Infraclass Teleostei Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Vertebrate biosphere covering redd fish behavior in situ jack jack salmon naturalworld nature precocial male precocious male salmonography.com spawning spawning act spawning behavior underwater underwaterphoto wild wild salmon
Sockeye Salmon female attacking a jack.
Sockeye Salmon (Oncorhynchus nerka) female attacking a jack. Aspect Ratio = 2:3.
Alaska wild salmon Class Actinopterygii Infraclass Teleostei Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Sockeye Salmon Subclass Neopterygii Summer Teleost Vertebrate aggression biosphere fighting fish behavior in situ naturalworld nature underwater underwaterphoto wild wild salmon
Spawning Coho Salmon including a jack
Coho Salmon (Oncorhynchus kisutch) including a jack commencing to spawn. Additional sneaker males entering the fray.
Actinopterygii Alaska Alaska wild salmon Autumn Chordata Class Actinopterygii Coho Salmon Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon South Central Alaska 2 Subclass Neopterygii Teleost Teleostei United States Vertebrate biosphere chordate in situ naturalworld nature underwater underwaterphoto wild wild salmon
Jack among other Coho Salmon
Coho Salmon (Oncorhynchus kisutch) jack or precocious male among other coho on their spawning migration in a tributary of Eyak Lake, Alaska. Aspect Ratio = 2:3.
Actinopterygii Alaska Alaska wild salmon Autumn Chordata Class Actinopterygii Coho Salmon Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon South Central Alaska 2 Subclass Neopterygii Teleost Teleostei United States Vertebrate biosphere chordate fish behavior in situ jack jack salmon naturalworld nature precocial male precocious male salmonography.com spawning migration underwater underwaterphoto wild wild salmon
A jack sneaking alongside a normal sized male Sockeye Salmon
A jack sneaking alongside a normal sized male Sockeye Salmon (Oncorhynchus nerka). Aspect Ratio = 4:5.
Actinopterygii Alaska Alaska wild salmon Chordata Class Actinopterygii Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Red Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Sockeye Salmon South Central Alaska 2 Subclass Neopterygii Teleost Teleostei United States Vertebrate biosphere chordate in situ jack jack salmon naturalworld nature precocial male precocious male salmonography.com underwater underwaterphoto wild wild salmon
Male and two jack Coho Salmon
Coho Salmon (Oncorhynchus kisutch) males during their spawning migration; the two smaller individuals are jacks or precocious males. Aspect ratio = 2:3.
Actinopterygii Alaska Alaska wild salmon Chordata Class Actinopterygii Coho Salmon Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon South Central Alaska 2 Subclass Neopterygii Teleost Teleostei United States Vertebrate biosphere chordate in situ jack jack salmon naturalworld nature precocial male precocious male underwater underwaterphoto wild wild salmon