Preliminary Study on the Use of Sargassum horneri as a Dietary Ingredient for Juvenile Rochia nilotica: Effects on Growth and Survival

Abstract

Simple Summary The marine gastropod Rochia nilotica is a valuable resource for Pacific Island nations, but its wild populations are rapidly declining. Farming these snails using conventional tank-culture methods is challenging because their growth is inherently slow when relying solely on natural algae attached to tank surfaces. To address this, a formulated feed incorporating Sargassum horneri—a brown macroalga that causes harmful ‘Golden Tide’ blooms—was evaluated in a proof-of-concept investigation. Juvenile snails were fed either the natural algae or a diet containing 40% S. horneri for 120 days in a pilot-scale trial in Micronesia. The top shells fed the formulated diet grew notably faster in shell width and gained substantially more weight than those that consumed natural algae, with a high survival rate of 94%. These preliminary findings suggest that S. horneri can potentially be utilized in aquaculture feed to support sustainable production of R. nilotica, fostering a circular economy that benefits both the environment and local economies.