Ichthyology is the branch of zoology (the study of animals) that deals with fish. It
includes the study of the development, anatomy (structure), physiology (function),
behavior, classification, genetics, and ecology of fish, among other things. Since
fish is a major food source for people, the study of ichthyology also has economic
importance.
History: The term "ichthyology" is derived from the Greek word "ichthys,"
which means "fish," and the Greek word "logos," which means "study" or
"science." Therefore, ichthyology literally means "the study of fish." The term was
coined in the 18th century, and its usage became more widespread in the 19th
century as the scientific study of fish gained momentum.
Why should we study ichthyology?
There are more than 22,000 known species of fish in the world, and they live in
nearly every imaginable body of water, from stagnant ponds to the deepest oceans.
They live in water all the time and breathe through gills. Together with mammals,
birds, reptiles, and amphibians, fish are one of the major groups of vertebrates
(animals with a backbone). They are considered the most successful vertebrate
group, outnumbering birds two to one and mammals seven to one. An
ichthyologist, therefore, must contend with a great variety of subjects, from the
bony, snakelike eel and the shark with all cartilage and no bone, to the
bioluminescent deep-sea fish that can make its own light.
Today, fish are not studied just for their own sake or to simply learn more about
them. Since fish are a major food source and fishing is an important industry, a
great deal of fishery research is conducted in government laboratories as well as
institutional aquariums. It is not surprising that much of this work is aimed at
learning more about diseases in fish as well as understanding the effect that
pollution has on them. Fish are as vulnerable to infections by viruses as are higher
vertebrates, and often they are the first to show signs of disease. They are also
susceptible to tumors, and sick fish are a signal that they live in an environmentally
degraded body of water. Increasingly, ichthyologists must know as much about the
environment of a certain type of fish as they do about the fish itself to note any
irregularities in the environment—and thus in the fish.