Survival and Growth Performance of Gracilariopsis chorda and Grateloupia divaricata Under High-Temperature and Low-Salinity Whiteleg Shrimp Culture Conditions

Abstract

Land-based aquaculture has emerged as an alternative to overcome the limitations of marine farming systems that are vulnerable to environmental fluctuations. The whiteleg shrimp (Litopenaeus vannamei) is one of the representative species cultured in land-based systems because it can be reared under low-salinity (approximately 15 PSU) and high-temperature (approximately 28°C) conditions. Seaweed co-culture has been suggested as a promising approach for enhancing resource production in land-based shrimp farming systems. However, knowledge regarding seaweed species that can survive and grow under these conditions is still insufficient. Therefore, expanding the range of potentially applicable seaweed species with economic value is necessary. In this study, two representative euryhaline red seaweeds, Gracilariopsis chorda and Grateloupia divaricata, were cultured using water from a land-based whiteleg shrimp culture system, and their survival and growth performance were evaluated. G. divaricata maintained a survival rate (SR) above 90% throughout the 3-week culture period, whereas the SR of G. chorda declined to below 40% after 2 weeks. During the culture period, the mean biomass of G. divaricata remained at 0.03 ± 0.01 g, whereas that of G. chorda decreased from 0.12 ± 0.02 to 0.03 ± 0.01 g. These results suggest that survival and growth responses may differ among seaweed species under environmental conditions characteristic of land-based whiteleg shrimp culture systems. This study provides a preliminary assessment of seaweed survival and growth performance and may serve as baseline information for future studies evaluating nutrient removal capacity, physiological characteristics and long-term cultivation performance.