Salmon bones and skeleton
What Makes a Salmon a Bony Fish?
A salmon is a bony fish because its skeleton is made mostly of bone. The skull, backbone, and ribs are made of bone. Salmon and most other bony fish have many thin bones too, called rays, inside their fins.
Skull bones form the frame for a salmon head. The skull bones include the upper and lower jaw and the brain case. Bony plates protect the gills that are located on the side of a salmon head.
The backbone forms the frame for the rest of a salmonbody. The backbone has lot of separate pieces of bone called vertebrae. The ribs are attached to the vertebrae.
Bony fin rays form the frame for a salmon fins. Fins help the fish swim and keep its balance.
What Is a Bony Fish?
Fish are vertebrates, which are animals with backbones. Fish live in water and usually breathe with gills. A bony fish is a fish whose skeleton is made mostly of bone. Salmon and trout are bony fish. Bass, catfish, flounder, barracuda, and seahorses are bony fish, too.
Altogether, there're about 24000 kinds of fish. Lots of these fish have bones. In spite of the fact there're 23000 kinds of bony fish. But some fish, including sharks and their relatives, have no bones at all. Instead they have skeletons made of a tough, rubbery material called cartilage.
The return of Atlantic salmon (Salmon salar) to their home river for spawning coincides with drastic skeletal alterations in both sexes. Salmon that survive spawning have to cope with the kype throughout their life, unless it disappears after spawning, as was suggested in the early literature. To understand the fate of the kype skeleton, we compared morphological and histological features of kypes from pre spawned mature anadromous males with post spawned males. In kelts, growth of the kype skeleton has stopped and skeletal needles are resorbed apically by osteoclasts. Simultaneously, and despite the critical physiological condition of the animals, proximal parts of the kype skeleton are remodelled and converted into regular dentary bone. Apical resorption of the skeleton explains reports of a decrease of the kype in kelts. The conversion of basal kype skeleton into regular dentary bone contributes to the elongation of the dentary and probably also to the development of a larger kype in repetitive spawning males.
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