Ichthyology

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 are a major food source for people, the study of ichthyology also has economic importance.

Taken from the Greek word ichthys for fish, ichthyology had its beginning with the Greek philosopher Aristotle (384–32 b.c.), since the ancient world was more interested in and more knowledgeable about fish than they were about many other animals. This may have been because fish were both a relatively easy-to-obtain source of food as well as an animal group that was readily accessible, since fishing is one of humankind's oldest occupations. Until the end of the nineteenth century, however, more attention was paid to describing and classifying fish than any other aspect. By then, ichthyology was well on its way to becoming a separate field of zoology. By the end of the first half of the twentieth century, the emergence of oceanography (the science of the ocean) and the newfound ability to conduct underwater observations, allowed scientists to be able to study fish in their natural environment for the first time. The development of improved techniques for keeping fish in tanks for study also spurred further advances.

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 of 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. Fishes 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 in order to note any irregularities in the environment—and thus in the fish.

[See alsoFish ]

Ichthyology

Ichthyology is the science of animals that deals with fish. This field includes the study of fish growth, development, structure, characteristics, classification, geographical distribution, and the relationship of fish to their environment. The science of ichthyology was evolved in Europe during the eighteenth century. However, the Chinese were studying fish (with the intention to propagate them) at least ten centuries before the birth of Christ. There are also recorded observations on the varieties, habits, and qualities of various fish by the ancient Egyptians, Greeks, and Romans.

Today, ichthyologists strive to answer questions like, "How long can a fish live?" and "How big can a fish grow?" Although these questions may sound simple, the answers are based on a multitude of factors. And while it may be true that most fish live between sixteen and twenty years, it is much more difficult to predict size because fish growth never stops. Generally, fish get a little longer and a little thicker every year. One of the largest fish, a 13.7-meter (45-foot) whale shark caught off Florida's Atlantic coast in 1912, was recorded at a weight of 20 tons.

One of the best places to study fish is the national fish collection, housed at the Smithsonian National Museum of Natural History. The collection is the largest in the world and contains approximately eight million species from all over the world. The collection continues to grow as specimens are added from parts of the world where the fish fauna is poorly recognized or understood. Zoologists from the National Marine Fisheries Service and the U.S. Department of Commerce are permanently stationed at the museum, and they work closely with the specimens, focusing primarily on commercially important species.

Stephanie A. Lanoue

Bibliography

Lagler, Karl F., John E. Bardach, and Robert R. Miller. Ichthyology. New York: JohnWiley & Sons, Inc., 1967.

ich·thy·ol·o·gy / ˌik[unvoicedth]ēˈäləjē/ • n. the branch of zoology that deals with fishes.DERIVATIVES: ich·thy·o·log·i·cal / -əˈläjikəl/ adj.ich·thy·ol·o·gist / -jist/ n.

ichthyology The study of fish. Originally this involved research on anatomy, classification, and the general biology of fish, but more recently research topics have included fish culture, fish diseases, conservation, and commercial fisheries.