Synaptula reticulata merupakan timun laut berdinding tubuh tipis dan memiliki warna kontras. Uji antifeedant ekstrak kasar Synaptula reticulata telah dilakukan pada tanggal 6-14 November di kedalaman 3-5 m Perairan Pulau Pramuka, Taman Nasional Kepulauan Seribu, DKI Jakarta. Sampel Synaptula reticulata berjumlah 171 individu dan dilarutkan dengan metanol. Persentase ekstrak kasar Synaptula reticulata yang didapat sebesar 8% dan memiliki konsentrasi fisiologis 40 mg/mL. Uji antifeedant dilakukan dengan membandingkan respon makan ikan karang terhadap pakan uji dan pakan kontrol. Pakan uji adalah ekstrak kasar Synaptula reticulata yang dicampur jelly dan pelet komersil. Pakan kontrol adalah campuran jelly dan pelet komersil tanpa dicampurkan ekstrak kasar Synaptula reticulata. Jumlah pakan uji yang dimakan sebanyak 3%, sedangkan jumlah pakan kontrol yang dimakan sebanyak 63%. Hasil uji statistik Chi-kuadrat pada tingkat kepercayaan 99% menunjukkan bahwa pemberian ekstrak kasar Synaptula reticulata berhubungan dengan respon makan ikan karang. Keeratan hubungan tersebut kuat, berdasarkan uji korelasi cremer (C = 0,63) terutama terhadap ikan karang family Pomacentridae dan Laberidae.

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Synaptula reticulata is sea cucumber that has thin body wall with contrasting color. Antifeedant activity assay from crude extract of Synaptula reticulata was conducted on 6th--10th November 2018 in 3--5 m of depth Pramuka Island water, Kepulauan Seribu National Park, DKI Jakarta. 171 individual Synaptula reticulata were collected and extracted using methanol. Crude extract percentage of Synaptula reticulata was 8% with a physiologycal concentration of 40 mg/mL. Antifeedant assay was done by comparing between coral reef fish feeding response to artificial test food and control food. Test food ware constitute of crude extract of Synaptula reticulata, jelly and pellet.

Control food contained jelly and pellet only. The amount of test food eaten as much as 3%, while the amount of control food eaten as much as 63%. Chi-Square analysis with confidence level of 0,01 showed that crude extract of Synaptula reticulata was correlated with feeding response of reef fishes. Cramer correlation test showed that crude extract Synaptula reticulata strongly related with feeding response of the treatments on reef fishes, with correlation value of 0,6.