Male Sockeye Salmon (Oncorhynchus nerka) threatens another male by raising his formidable jaws with this tilted head posture in an Alaskan stream during early summer.

A Pink Salmon (Oncorhynchus gorbuscha) sneaker male courts a female building her redd while the alpha male is away fighting in an Alaskan intertidal stream during the summer.

Male Sockeye Salmon (Oncorhynchus nerka) threatens another male by raising his jaws and tilting his head, Southcentral Alaska, Summer

Coho Salmon (Oncorhynchus kisutch) in the act of spawning in an Alaska stream during autumn.

Pink Salmon (Oncorhynchus gorbuscha) summer spawning migration in a tributary of Prince William Sound, Alaska.

Mature male Sockeye Salmon, also known as Red Salmon (Oncorhynchus nerka) in an Alaskan stream during the summer, South-central Alaska; Alaska, United States of America

Sockeye Salmon, also known as Red Salmon (Oncorhynchus nerka) probes her redd while a male guards in an Alaskan stream during the summer; Alaska, United States of America

Sockeye Salmon, also known as Red Salmon (Oncorhynchus nerka) male crosses over a female as part of courtship in an Alaskan stream during the summer; Alaska, United States of America

Sockeye Salmon, also known as Red Salmon (Oncorhynchus nerka) spawning pair in an Alaskan stream during the summer; Alaska, United States of America

A female Sockeye Salmon, also known as Red Salmon (Oncorhynchus nerka) attacking a female who is excavating a redd that is too close to hers in an Alaskan stream during the summer; Alaska, United States of America

Chum salmon heads hang drying in the sun outside of a smokehouse, Kobuk, Arctic Alaska, summer

Sockeye Salmon, also known as Red Salmon (Oncorhynchus nerka) spawning pair in an Alaska stream during the summer, South-central Alaska; Alaska, United States of America

Close up of the jaws and teeth of a male Chum Salmon (Oncorhynchus keta) underwater view in an Alaskan stream during the summer.