Seabass and gilthead seabream are the two marine fish species that have characterized the development of marine aquaculture in the Mediterranean basin over the last three decades. The substantial increase in production levels of these two species that used to be high-level value ones and now are considerably cheaper was made possible by the progressive improvement of technologies for fry production in hatcheries. As a result, more than 100 hatcheries have been built in the Mediterranean basin, working on these and other similar species. At present the farmed production of these two species derived from hatchery produced fry is far greater than the supply coming from capture fisheries. This second and final volume of the manual deals with the design and construction of the hatchery and its various sections, engineering aspects of water supply, hydraulic circuits, and equipment used in the hatcheries. And it also includes guidance on financial aspects that could be useful for the project design, and operation of hatcheries.