Optimization of seaweed farming: the impact of Perna viridis density on Gracilaria verrucosa in extensive ponds

Abstract

The cultivation of Gracilaria verrucosa seaweed is a significant aquaculture endeavor, particularly within polyculture systems with green mussels (Perna viridis). The number of green mussels in ponds can influence water quality and the growth of planted seaweed. This study seeks to evaluate the influence of Perna viridis density on the development and water quality in the cultivation of Gracilaria verrucosa in vast ponds located in Pangkahkulon Village. A fully randomized design (CRD) was implemented, including three treatments with green mussel densities of 10, 20, and 30 mussels/m², each duplicated three times, yielding nine experimental units. The observed characteristics comprised the specific growth rate (SGR), thallus length (both horizontal and vertical), and water quality. The findings indicated that the density of green mussels had a significant impact on the specific growth rate of Gracilaria verrucosa, with treatment A (10 mussels/m²) demonstrating the greatest growth rates of 6.65±0.11 on day 7 and 5.08±0.01 on day 21. Treatment C (30 mussels/m²) had the lowest growth rate, measuring 0.96±1.08 on day 7 and 4.07±0.19 on day 21. Mussel density affected thallus length, although the impact was not substantial. On day 21, treatment A exhibited the greatest vertical thallus length (4.2±4.05 cm) and the largest horizontal thallus length (5.2±2.25 cm). This work offers significant insights into the regulation of green mussel density in polyculture systems to enhance seaweed development and preserve water quality.