Ichthyology is the branch of zoology devoted to the study of fish. This includes the bony fish (Osteichthyes), the cartilaginous fish (Chondrichthyes) such as sharks and rays, and the jawless fish (Agnatha). Since there are as many species of fish as all other vertebrates put together, and they have been evolving for a very long time, there is a bewildering variety; while most species have probably been found and described, there is much that is still not known about biology and behavior.
The first scientific description of fish occurs in Aristotle, who mentions various facts about 118 species. Little additional work is known until the 1500s, when Guillaume Rondelet published his De Piscibus Marinum describing 244 species. During the 1600s, explorers found new types of fish; George Markgraf 's Naturalis Brasilae added another 100 species, and in 1686 the Historia Piscium of John Ray and Francis Willughby described over 400 species.
The title "father of ichthyology" belongs to Peter Artedi, a student of Linnaeus who identified five orders of "fishes" (including cetaceans) and divided those into genera. Artedi drowned by accident in an Amsterdam canal in 1735, and Linnaeus published his manuscripts posthumously.
In the 1780s Marcus Elieser Bloch published Ichthyologia as a series of volumes of plates, and after he died, his associate Johann Gottlob Schneider published the M. E. Blochii Systemae Ichthyologiae describing 1,519 species.
Georges Cuvier's Regne animal distribu d’aprs son organisation of 1817-1830 was a key step forward for fish classification, and Cuvier worked with his student Achille Valenciennes to produce the 22-volume Histoire Naturelle des Poissons in the 1830s - though never completed, the work described 4,514 species.
The greatest ichthyologist around the beginning of the 20th century is generally considered to be David Starr Jordan, who wrote 650 articles and books on the subject, in addition to serving as president of Indiana University and Stanford University.
The names are followed by their fields of specialization and major contributions: