SEMARANG – A team of Diponegoro University (UNDIP) Semarang Student Creativity Program succeeded in creating turtle and rabbitfish (siganussp) repellent device which is useful for preventing crop failure of seaweed cultivation in Karimunjawa, Jepara, Central Java. Sea turtles and rabbitfish have been identified as causes of failed seaweed harvest done by the fishermen in small islands.
The team consists of Muhammad Syahril Munthe, Izzatun Nuha, Nuraini Elvi Fajrin, Berlian Ade Wijaya, and assisted by Prof. Dr. Aristi Dian Purnama Fitri, S.Pi, M.Si. The research and manufacturing process of the tool is supported by Student Creativity Program 2020 which funding is from the Directorate of Learning and Student Affairs, Directorate General of Higher Education, Ministry of Education and Culture.
As the known fact, in Karimunjawa Islands most of the people rely on the sea as their source of life. In addition to fishing, residents have made seaweed cultivation as source of income, as well as a sustainable business. In extreme climatic conditions, seaweed management can be a productive activity for residents. Therefore, optimizing the harvest is important.
From the story of fishermen who are involved in seaweed cultivation, they often experience crop failures. The identification results show that one of the causes of the failure to harvest seaweed is due to attacks by sea turtle and rabbitfish. Both species in the context of seaweed cultivation are considered pests.
Referring to existing reports, attacks by sea turtles and rabbitfish can cause seaweed production to fall by up to 50%. In a condition where the selling price of seaweed is fluctuating, a 50% decline in production is very disturbing to the income of fishermen in Karimunjawa.
So far, they have had problems in cultivating seaweed because their plants are often attacked by turtles and baronang fish. Therefore, an idea emerged to optimize harvest by using simple technology.
The Undip Student Creativity Program team which conducted a study in Karimunjawa then designed a tool that could drive sea turtle and rabbitfish from seaweed cultivation area. The design received support from the Ministry of Education and Culture through the Director General of Higher Education.
The form of the tool created by the Undip Student Creativity Program Team is a box equipped with green LED lights, speakers, body, and a series of selvoltaic. This tool can emit high frequencies which are then caught by the rabbitfish through their scales. By catching this frequency, the rabbitfish will move away to a position up to 3 meters from seaweed cultivation area.
Meanwhile, sea turtle can also be driven away from getting close to the seaweed cultivation area using this tool. The mechanism is from the green glow from LED emission which is not liked by sea turtle, so they will avoid it. The tool is designed automatically and repeatedly in 15 seconds, off five seconds in order to save energy.
The process of making tools and trials has been carried out from August 10th to September 30th 2020. This innovation from Undip Student Creativity Program Team is expected to be able to increase the seaweed cultivation in Karimunjawa with environmentally friendly way since it does not use chemicals that can pollute marine waters.
