The shortage of marine resources calls for the implementation of new technological processes for providing a better utilization of waste and by-products from fisheries and fish processing activities. Most of these by-products are currently used as raw materials for animal feed. It is estimated that their utilization in human foodstuffs, nutraceuticals, pharmacy, or cosmetics would increase their value fivefold. This book discusses the opportunities for upgrading these materials by means of basic technologies such as hydrolysis, membrane ultrafiltration, and better handling techniques.