The Effect of Different Media and Shelf Life on the Growth and Agar Content of Seaweed Seeds (Gracilaria verrucosa)

Gracilaria is a type of seaweed that is widely cultivated around the world due to its antibacterial compounds and high economic value. This plant adapts quickly to ponds with fluctuating water quality conditions, making it easy to cultivate. However, there are several challenges related to seeds quality including media and shelf life which play a significant role. This research aimed to analyze effective media and optimal shelf life for Gracillaria verrucosa seeds.The method used was a laboratory experimental design with a randomized block design that includes two treatments and three replications of each. The difference in the first treatment was in media (straw, sawdust, and ice blokcs), while in the second treatment was shelf life (24, 48, and 72 hours). The parameters observed were the growth weight and agar content of G. verrucosa, as well as water quality (temperature, pH, dissolved oxygen, salinity, ammonia, nitrate, nitrite, and phosphate). The research results showed that the growing media and shelf life significantly affect the growth of G. verrucosa seaweed seedlings, as indicated by the difference in absolute growth rate and specific growth rate in each treatment. The use of sawdust and straw as media for seaweed seeds has a significantly higher effect on weight gain and growth rate of G. verrucosa compared to ice blocks. However, the best media was sawdust. Seaweed seeds stored for 72 hours exhibit higher weight gain and growth rates compared to those stored for 24 and 48 hours. Shelf life also affected the agar content of G. verrucosa seaweed. The longer the shelf life, the higher the agar content tended to be.