Graphics Reference
In-Depth Information
A number of fish also possess fleshy extensions on their mouths, known as
barbels. These soft, fleshy extensions of the mouth enable fish to locate food
through taste. The barbs vary in number: The tench
Tinca tinca
has two, the
barbel
Barbus barbus
has four, and the stone loach
Noemacheilus barbatulus
has six. Some fish that have these barbels are very small; others are longer and
more substantial.
FIG 4.69
The fish in this example
has a subterminal mouth and a set of
four barbels.
A fish's nostrils are known as
nares
. Unlike birds' and mammals' nostrils, these
are not used to breathe; they are used for a sense of smell, detecting food, and
detecting pheromones and thereby assisting in the mating process. They may
even play a part in salmon being able to locate the exact place at which they
were spawned after a journey of several thousand miles.
FIG 4.70
The direction of the
movement of an object through space
(in this instance a fish) is denoted by
three terms. a: Pitch. b: Roll. c: Yaw.
The same terms are applied to birds
and aircraft in flight.
Fish Movement
The stability of fish, their orientation, and their movement are not at all
dissimilar to those of birds, boats, and airplanes and are described in the
(a)
(b)
(c)
