**Abstract**

Generally, in different countries, strategies to improve food security have focused on increasing food production, which contributes to climate pollution and increases stress on scarce natural resources such as water and land. Due to the increase of world population (estimated to be 9 milliards in 2050), to the limited biological resources and to the increase of environmental pollution, there is a need in innovation in food industry. This can be done by improving food quality through new technologies for valorization of food and food by-products. According to Food and Agriculture Organization (FAO), one third of world food production is lost or wasted along the food supply chain. In the sector of fisheries and aquaculture, 35% of the world's harvest is lost or wasted each year. Thus, the valorization of marine by-products should be an obligation to assure the world food security and to satisfy the growing demand for fishery products. The objectives of this study are: First to review the sources of by-products and their characteristics and second to describe and evaluate the different technologies that are or can be used to valorize marine by-products in production of marine oils and concentrated fatty acids.

**Keywords:** by-products, valorization, technologies, fish, marine oil, n-3 fatty acids
