The purpose of the third edition is to provide modern knowledge to both geotechnical and biological science students and users of coastal ecosystems as a reference for their biological activities in the space 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, as well as their age estimation, population, and management. Finally, various species of fish in Greek waters are described, as well as those deemed necessary internationally.

More specifically, the first chapter deals with the main physicochemical properties of water masses (fresh and saltwater). 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 about their population estimates. The eighth chapter describes in detail the most important species of fish found in fresh and saltwater in our country, while the ninth refers to the basic knowledge that someone dealing with ichthyological handling of inland and saltwater should have.