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 converters of protein into fish flesh. Species of the genus Medialuna fish have been reported as a fast-growing, short-lived species. The native fish Acha (Medialuna ancietae Chirichigno 1987) 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 feeding 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 268 ± 5.9 mg/100 g of the essential 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 concentrate them from potentially cultivable macroalgae. M. ancietae has potential for sustainable aquaculture production as a contribution to nutrition security and the re-stocking of wild populations.

Describe the embryonic development of Paralabrax humeralis (Peruvian rock seabass) and the present morphology of its eggs and yolk-sac larvae using the eggs spawned by P. humeralis broodstock in captivity. The spawning occurred naturally and spontaneously in early November 2018. The egg is pelagic and round, with a diameter of 0.98 ± 0.02 mm, an oil globule, and a diameter of 0.2 ± 0.02 mm. Embryonic development started with meroblastic cleavage, reaching the first cleavage stage at 0.4 h post-fertilization (HPF), and reached 64 cells at 2.2 HPF. Blastula period, 128 cells to 30% epiboly, end at 11.3 HPF. Gastrula period, 50% epiboly to 90% epiboly, end at 19.6 HPF. In the organogenesis period, forming Kupffer’s vesicle appeared at 22.5 HPF, the separation of the caudal fin from the yolk at 30.3 HPF, and the hatching of the first larvae at 47.9 HPF. Water temperature was kept at 17.2 ± 0.2°C. The yolk-sac larvae measured 2.22 ± 0.1 mm with a pigmentation pattern of pinpoint melanophores, all along with the embryo and xanthophores in the cephalic region, trunk, and caudal region, as well as in the oil globule. The larva takes feeds from three days post-hatch-out.

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.