Herbivore Fish as Sustainable Alternative for Nutrition Security: Food Habits and Nutritional Composition of the Acha Fish (Medialuna Ancietae) in Northern Chile.

Sustainability in aquaculture is a necessity of the future, not only as the most promising means of supplying the protein that the world will require to feed its growing population but to offer needed conservation of the world’s ocean resources. The use of wild fish inputs in farm-raised fish outputs has been a primary concern of sustainability in aquaculture production. Herbivorous fish are more efficient convertors of protein into fish flesh. Species of the genus Medialuna fish have been reported as a fast-growing, short-lived species. The endemic Acha fish ( Medialuna ancietae ) in the Northern part of Chile is an over-exploited fish that has been associated with aquatic vegetation as a food source. We studied the eating habits and nutritional composition of M. ancietae. For this, we developed a reference collection of marine macroalga (epidermis and nutritional composition) observed in the diet of individuals of this species for the study of digestive material. More than 90% of the components found were marine macroalgae, indicating that M. ancietae is an herbivorous fish. Compared to non-herbivorous fish our results showed that most of the nutrients present in the Medialuna diet are found at much lower levels including n-3 long-chain polyunsaturated fatty acids (49.7%) and protein (13–60%). M. ancietae meat provides essential components of human nutrition with a significant protein content (18.99 ± 0.26%) and the presence of n-3 long-chain polyunsaturated fatty acids. Most fed aquaculture non-herbivorous species rely on wild-captured fish for these essential nutrients, while M. ancietae can obtain and has the ability to concentrate them from potentially cultivable macroalgae. M. ancietae has potential for a sustainable aquaculture production as a contribution to nutrition security and re-stocking of wild populations.