No abstract

Reductions of its natural populations have led to recent efforts in small-scale aquaculture of the freshwater prawn Cryphiops caementarius, either for conservation or commercial purposes. However, the lack of knowledge about its nutritional requirements has been one of the major obstacles for its successful culture. Given its importance, this study determines and compares the chemical composition (moisture, ash, crude protein, total lipids and nitrogen free extract) of whole animals and main storage tissues (gonad, hepatopancreas and muscle), of C. caementarius adult prawns from two natural populations. Moreover, the relation of this composition with reproductive and environmental parameters (sex, maturation and habitat) is discussed. The specimens were collected in Limarí and Choapa rivers (Coquimbo, Chile) during reproductive season, and divided into six categories according to capture location, gonad maturation stage, and gender. The chemical composition of whole animals and storage tissues was compared among categories. Significant differences were observed between tissues, sexes, maturity stages and locations. Regarding tissues, the muscle and the gonads were rich in protein, whereas the hepatopancreas had high lipid content. According to results, factors such as sex, habitat and stage of gonad maturation can modify the biochemistry of C. caementarius. Nonetheless, the main chemical variations were observed in tissues involved in regulatory processes (hepatopancreas and gonads), and to a lesser extent in structural tissues (muscle). This is the first study known that reports information about the biochemistry of C. caementarius and its findings may be useful to improve feeding practices in aquaculture.

The variation in saline requirements during larval development of Cryphiops caementarius establishes a particular coexistence in the culture systems between the shrimp larvae, the microalgae and Artemia nauplii. Although the technology for the mass production of freshwater prawn juveniles has advanced positively, the non-commercial availability of an exclusive live feed for amphidromous crustaceans, such as C. caementarius, has created the need to optimize the management of organisms commonly used as feed in the larval culture of marine crustaceans. We investigated the effect of salinity on embryonic development dynamics and the hatching rate of commercial Artemia sp. cysts, including the effect of cooling decapsulated cysts on the hatching rate, and the effect of salinity on the behavior of marine microalgae used as live feed in the larviculture of C. caementarius. The results encourage a sustained and stable production of Artemia nauplii at different salinities, and at the same time, reduce by 80% the daily time used in feeding activities. Also, the information generated in this study adds critical information about activities and procedures for the larviculture of the northern river shrimp, which could be used to improve larval feeding strategies either in C. caementarius or in other amphidromous crustacean species.