The purpose of the third edition is to equip both students of geotechnical and biological sciences and users of coastal ecosystems with modern knowledge, serving as a reference for the biological activities of the area they use.

The content of the book refers to the main physicochemical properties of water masses, the physiology, anatomy, reproduction, and feeding habits of fish, the estimation of their age and population, as well as their management. Finally, various species of fish in Greek waters and, where deemed necessary, international waters are described.

More specifically, the first chapter deals with the main physicochemical properties of water masses (fresh and salty). The second chapter refers to the physiology and anatomy of fish, while the third refers to their reproduction. The fourth chapter deals with the geographical distribution and migration of fish, while the fifth refers to their age. The sixth chapter deals with the food and feeding habits of fish, while the seventh expands, as much as possible, on the fundamental knowledge regarding the estimation of their population. The eighth chapter describes in every possible detail the most important fish species found in the fresh and sea waters of our country, while the ninth refers to the basic knowledge that one should have when dealing with the ichthyological management of inland and salty waters.