c. Paired Fins.
(1) Pectoral fin. The pectoral fins are located posterior to the gill openings
(and gill cover). They correspond in position to human arms.
(2) Pelvic fin. The pelvic fins are located on the belly (on the ventral border)
posterior to the pectoral fins. They correspond in position to human legs.
INTERNAL IDENTIFICATION - CHARACTERISTICS
a. General. As a rule, internal anatomical features are of limited importance to
the inspector since most fish are eviscerated prior to being offered to the military
services. However, examination of the visceral cavity (the poke) is necessary to detect
b. Gills. Gills are the respiratory system of the fish. They are set behind the
cavity of the mouth and consist of bony arches to which the gill filaments are attached.
Figure 1-2. Internal features of fish.
c. Mouth. The shape, size, and location of the mouth vary greatly in different
species. The jaws and various areas inside the mouth and gullet usually have true
d. Air Bladder. This is an elongated sac with a semitransparent wall that lies
close to the backbone in the abdominal cavity. Its chief purpose is to provide proper
buoyance for the fish. Many fish do not have an air bladder.
e. Kidney. This is an elongated dark organ resembling black jelly that lies in the
abdominal cavity, close to the backbone. It is highly vascular and is one of the points
f. Muscles. The muscles of fish are segmented or layered, resulting in a flaked
texture when cooked. The flesh of fish consists of two types of muscles (Figure 1-3).