Salmon have a standard fish body form. Like most fish they have a
mouth, pair of eyes and a pair of nostrils (nares) in their head. Most fish,
including salmon, also have three midline fins (dorsal, caudal, and anal) as
well as two types of paired fins (pectoral and pelvic).
Salmon have three obvious unique characteristics that can be used to
separate them from other fish anatomically. These are as follows: (1) all of
their fins are supported by soft fin rays (no spines), (2) their second dorsal
fin is an adipose (fleshy) fin and lacks any fin supports and (3) they have an
axillary process (a small bump on their body) where each pelvic fin joins the
body.
Salmon skin is covered with protective scales, secreted by the
epidermal (skin) cells. Salmon scales are all cycloid, with concentric rings.
These rings can be counted for age.
Salmon all have gills, for oxygen and carbon dioxide exchange. Water
enters the mouth, flows across the gills in the back of the throat, and out the
gill slit on each side of the body. Gill rakers, on their gills, are used to
strain plankton from the water in some species. Each gill slit is supported by
a bony operculum as is present in most bony fish. [The sharks and the rays also
have gill slits but they usually have 5-7 pair on each side and none are
supported by bone).
Salmon have excellent vision. They can see both in front of their
bodies and to the sides. Salmon can also see colors and are good at judging
distances both in and out of the water. The have been known to jump out of the
water to catch a flying dragonfly out of the air. This means that they have the
ability to interpret how light bends when entering the water and account for
this when they aim for airborne prey. Salmon are also known to be able to see
terrestrial predators from under the water and swim for cover. It is thought
that they have the ability to focus both at close range and far away as well
has have the ability to see and interpret movement.
mouth, pair of eyes and a pair of nostrils (nares) in their head. Most fish,
including salmon, also have three midline fins (dorsal, caudal, and anal) as
well as two types of paired fins (pectoral and pelvic).
Salmon have three obvious unique characteristics that can be used to
separate them from other fish anatomically. These are as follows: (1) all of
their fins are supported by soft fin rays (no spines), (2) their second dorsal
fin is an adipose (fleshy) fin and lacks any fin supports and (3) they have an
axillary process (a small bump on their body) where each pelvic fin joins the
body.
Salmon skin is covered with protective scales, secreted by the
epidermal (skin) cells. Salmon scales are all cycloid, with concentric rings.
These rings can be counted for age.
Salmon all have gills, for oxygen and carbon dioxide exchange. Water
enters the mouth, flows across the gills in the back of the throat, and out the
gill slit on each side of the body. Gill rakers, on their gills, are used to
strain plankton from the water in some species. Each gill slit is supported by
a bony operculum as is present in most bony fish. [The sharks and the rays also
have gill slits but they usually have 5-7 pair on each side and none are
supported by bone).
Salmon have excellent vision. They can see both in front of their
bodies and to the sides. Salmon can also see colors and are good at judging
distances both in and out of the water. The have been known to jump out of the
water to catch a flying dragonfly out of the air. This means that they have the
ability to interpret how light bends when entering the water and account for
this when they aim for airborne prey. Salmon are also known to be able to see
terrestrial predators from under the water and swim for cover. It is thought
that they have the ability to focus both at close range and far away as well
has have the ability to see and interpret movement.