Effects of Salinity on Growth and Survival of Macrobrachium spp. Larvae under Hatchery Conditions

Salinity is a pivotal environmental parameter governing osmoregulation, metabolism, and survival in freshwater prawn larvae. This study investigated the effects of four salinity levels (0, 5, 10, and 15 ppt) on the growth performance and survival of Macrobrachium spp. larvae under controlled hatchery conditions in Kenya. Newly hatched larvae were stocked at 70 individuals per 500mL concal flasks across four treatments conducted in triplicate, following a Completely Randomized Design (CRD). Salinity was adjusted gradually (2 ppt/day) to minimize osmotic stress, and larvae were fed freshly hatched Artemia nauplii three times daily. Daily mortality was recorded across all treatments over a 9-day trial period. Preliminary findings indicate differential survival across salinity treatments, with 15 ppt showing comparatively sustained larval persistence relative to 0 and 5 ppt treatments. Growth and motility data are being finalized in an ongoing trial. Results are expected to identify the optimal salinity range for Macrobrachium larval rearing, providing evidence-based guidance for hatchery management and sustainable prawn aquaculture in the East African region.

Broodstock maintained at 5 ppt, 30°C. Upon hatching, larvae acclimatized for 24 hours before assignment to treatments. Salinity moderated via mixing filtered seawater and freshwater, monitored daily by refractometer. Water quality (temperature, DO, pH) maintained within optimal ranges. Growth measured by larval length and weight; survival calculated as percentage of initial stock surviving at trial end.