Abstract
The mass production of the marine copepod Apocyclops dengizicus was developed using microalgal diets (Nannochloropsis oculata, Tetraselmis suecica, and Chloroidium saccharophilum) under optimized environmental conditions. The size spectrum of A. dengizicus nauplii (N I-N VI) and copepodids. (C I-C VI) indicate their superiority as a replacement for Rotifers and Artemia nauplii live feeds in fish larval rearing, and stage-specific harvesting protocols were established to provide appropriately sized prey. (nauplii, copepodites, and adults) for marine finfish. In a 21 days culture period with the N. oculata diet hundred percent survival of A. dengizicus was an advantageous factor for this species. Furthermore, during the 21st day of culture period, high fecundity (21 ± 1 eggs per clutch) and attainment of high population density (13,000 ± 217 individuals/L) are ideal features recorded in this species. Fatty acid profiling of this species indicated rich in essential long-chain polyunsaturated fatty acids (LC-PUFAs), with DHA at 2.52% in nauplii, 3.97% in copepodites, and 5.17% in adults; EPA at 2.42%, 2.58%, and 2.51%, respectively; and ARA at 0.93% in copepodites and 1.43% in adults. This highlights the strong nutritional compatibility with marine finfish larvae. GC-MS analysis identified antioxidant and antimicrobial compounds, including 7,9-di-tert-butyl-1-oxaspiro(4,5)deca-6 and L-(+)-ascorbic acid 2,6-dihexadecanoate, which may mitigate bacterial infections and oxidative stress. Overall, A. dengizicus demonstrates high survival, reproductive performance, population density, and rich nutritional content, confirming its potential as a sustainable, high-quality, and functional live feed for marine finfish hatchery seed production.