Underwater view of a sockeye salmon (Oncorhynchus nerka) spawning pair and a challenger male in Power Creek near Cordova, Alaska in the summer; Alaska, United States of America

Underwater view of a sockeye salmon (Oncorhynchus nerka) spawning pair and a sneaker male in Power Creek near Cordova, Alaska in the summer; Alaska, United States of America

Underwater view of a sockeye salmon (Oncorhynchus nerka) spawning pair and a challenger male in Power Creek near Cordova, Alaska in the summer; Alaska, United States of America

Animals

Underwater view of caddisfly larvea consuming a sockeye salmon carcass in Power Creek near Cordova, Alaska in the summer; Alaska, United States of America

Animals

Animals

Underwater view of a gaping male pink salmon (Oncorhynchus gorbuscha) in Hartney Creek near Cordova, Alaska in the summer; Alaska, United States of America

Underwater view of a male pink salmon (Oncorhynchus gorbuscha) in Hartney Creek near Cordova, Alaska in the summer; Alaska, United States of America

Underwater view of a coho salmon (Oncorhynchus kisutch) spawning in Power Creek near Cordova, Alaska in the autumn; Alaska, United States of America

Animals

Male Sockeye Salmon (Oncorhynchus nerka) threatens another male by raising his formidable jaws with this tilted head posture, underwater view in an Alaskan stream during early summer; Cordova, Alaska, United States of America

Red salmon fighting in shallow water; Paxson, 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

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

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

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

Incidental tree branch bites can result from the aggressive behavior of male Sockeye Salmon, also known as Red Salmon (Oncorhynchus nerka) competing to spawn in an Alaskan stream during the summer; Alaska, United States of America

Underwater view of King Salmon (Class Actinopterygii) in Moose Creek, a tributary of the Deshka River, South-central Alaska; Alaska, United States of America

Sockeye Salmon, also known as Red Salmon (Oncorhynchus nerka) male threatening a challenger by also raising his snout 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

Male Chinook Salmon, also known as King Salmon (Oncorhynchus tshawytscha) prior to spawning in a tributary of the Deshka River in summer; Alaska, United States of America

Coho Salmon, also known as Silver Salmon (Oncorhynchus kisutch) crosses over the tail end of a female as part of courtship in an Alaskan stream during the summer; Alaska, United States of America

Underwater view of a competing sockeye salmon (Oncorhynchus nerka) in Power Creek near Cordova, Alaska in the summer; Alaska, United States of America