Energetic performance and growth of Tripneustes ventricosus under variable water quality conditions: implications for aquaculture

Abstract Tripneustes ventricosus (Lamarck 1816) is one of the largest and most commercially valuable sea urchins in the Caribbean. This study examined the effects of key water quality parameters on the energetic physiology of adult individuals under controlled conditions to establish the basis for their reproductive conditioning and culture. Three 30-day experiments independently assess the effects of temperature (24, 27, 30 °C), oxygen saturation (55 and 70%), and ammonia concentration (20, 30, 50 µg NH 3 -N L −1 ). Energetic physiological responses were measured in terms of ingestion rate (IR), absorption efficiency (AE), absorption rate (AR), oxygen consumption rate (OCR), ammonium excretion rate (UR), scope for growth (SFG), gross ( K 1 ) and net ( K 2 ) somatic growth efficiencies, feed conversion ratio (FCR), specific growth rate (SGR), RNA/DNA ratio, body compartment indices (BCI), and tissue biochemical composition. Increasing temperature had no effect on energy acquisition, but at 30 °C, metabolic expenditures increased (higher OCR and UR) while SFG, K 1 , K 2 , and carbohydrate reserves declined. Moderate hypoxia (55% saturation) increased OCR and UR and decreased IR, AR, SFG, K 1 , K 2 , and SGR. Elevated ammonia concentrations (≥ 30 µg NH 3 -N L −1 ) reduced IR, AR, OCR, and SFG, and increased UR. AE and most growth and storage-related variables were not significantly affected by any of the tested variables. Together, these results identify SFG, K 1 , and K 2 as highly sensitive indicators of short-term changes in water quality and clarify how different stressors independently alter energetic balance. Optimal physiological performance occurred at 24–27 °C, ≥ 70% oxygen saturation, and ≤ 20 µg NH 3 -N L −1 ammonia. The findings outline optimal conditions for T. ventricosus aquaculture. These findings define environmental thresholds relevant for husbandry and support the refinement of aquaculture practices for T. ventricosus .