Gulping and burping air

Salmon have a physostomous air bladder. A physostomous air bladder is one that is connected to the mouth via the alimentary canal. The air bladder is the organ for providing neutral bouyancy that is found in several groups of fishes. If a salmon becomes negatively bouyant it will rise to the surface an gulp air to fill its bladder. Conversely a salmon may burp air to reduce bouyancy.

Burping bladder air
This female Sockeye Salmon (Oncorhynchus nerka) is burping air from her physostomous airbladder as she commences to spawn.
Actinopterygii Alaska Animal Biology Chordata Class Actinopterygii Ecology Infraclass Teleostei Neopterygii Oncorhynchus nerka Pacific salmon Phylum Chordata Power Creek Red Salmon Salmonidae Salmoniformes Salmoninae Seacam underwater housing Sockeye Salmon South Central Alaska Subclass Neopterygii Summer Teleost Teleostei United States Vertebrate biological biosphere burp chordate in situ living naturalworld nature near Cordova organism physostomous airbladder underwater underwaterphoto wild www.salmonography.com
The descent
After gulping air to fill her air baldder, this maturing female Coho Salmon (Oncorhynchus kisutch) descends to rejoin a school of milling conspecifics and a Sockeye Salmon (O. nerka) jack (center of frame).
Actinopterygii Animal Autumn Biology Chordata Class Actinopterygii Coho Salmon Ecology Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Teleostei Vertebrate anadromous anadromy biological biosphere chordate diadromous diadromy fresh water freshwater gulping air in situ living lotic migratory naturalworld nature organism semelparity semelparous stream under fresh water underwater underwaterphoto wild www.salmonography.com
Waiting to mature
While several Coho Salmon (Oncorhynchus kisutch) undergoing sexual maturation rest near their spawning grounds one is reaching for the surface to gulp air for its swimbladder.
Actinopterygii Animal Autumn Biology Chordata Class Actinopterygii Coho Salmon Ecology Infraclass Teleostei Neopterygii Oncorhynchus kisutch Pacific salmon Phylum Chordata Salmonidae Salmoniformes Salmoninae Seacam underwater housing Silver Salmon Subclass Neopterygii Teleost Teleostei Vertebrate biological biosphere chordate gulping air in situ living naturalworld nature organism underwater underwaterphoto wild www.salmonography.com
The gulp
A female Sockeye Salmon (Oncorhynchus nerka) has broken away from a schooled group of staging conspecifics to gulp air at the surface for physostomous air bladder.
Actinopterygii Alaska Animal Biology Chordata Class Actinopterygii Copper River Delta Ecology 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 Teleost Teleostei United States Vertebrate biological biosphere chordate gulping air in situ living naturalworld nature organism physostomous staging summer underwater underwaterphoto wild
The gulp
A female Sockeye Salmon (Oncorhynchus nerka) has broken away from a schooled group of staging conspecifics to gulp air at the surface for physostomous air bladder.
Actinopterygii Alaska Animal Biology Chordata Class Actinopterygii Copper River Delta Ecology 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 biological biosphere chordate gulping air in situ living naturalworld nature organism physostomous staging underwater underwaterphoto wild