Abstrak
Marine algae macro is a biological resource that has been utilized by Indonesian people as a livelihood, and several areas make it their main livelihood. Many developed countries use macro marine algae as raw material for their production, one of which is the raw material for cosmetics. Ice-ice is a disease that attacks seaweed a lot. This disease is characterized by the appearance of red spots / patches on part of the thallus which gradually turn pale yellow and eventually turn white. The thallus becomes brittle and breaks easily. This study aims to determine the rate of attack of ice-ice in seaweed cultivation using the off-bottom method in Hundihuk Village, Rote Northwest District. Observations of seaweed recession to the invention of ice-ice were carried out every week for 49 days and also measured water parameters including temperature, salinity, pH, DO, brightness, and current velocity. The results of the research obtained show that ice-ice disease in the waters of Hundihuk Village still occurs by attacks of ice-ice disease. This can be seen from the incidence rate of incidence rate and intensity rate with the highest incidence rate of 34.0%, intensity value 2.3%, incidence rate 3.64% and intensity rate of 9.21%. Symptoms of ice-ice that arise include: rough surface of the thallus, white spots appear on the surface of the thallus, the thalus becomes slimy and white, which eventually crumbles. Changes in environmental parameters temperature, salinity, DO, brightness and current velocity also affect the rate of spread of ice-ice disease.