Judul: Temporal Pattern of Coral Reef Fish Comunity in Tidung Kecil Island Using eDNA Metabarcoding and Underwater Visual Census
Abstrak: Coral reef fish is one of the indicator for assessing the level of biodiversity of a coral reef ecosystem. The existence of coral reef fish can be affected by anthropogenic and natural factors, one of which is a seasonal variability. Various studies have reported that the structure of fish communities can be influenced by seasonal variations. Seasonal monitoring is important to detect temporal variation in fish communities. This study aims to assess the structure of coral reef fish communities based on seasons in Tidung Kecil Island using environmental DNA metabarcoding and Underwater visual census. Underwater visual census was conducted on 250 m2 and 1 L water sample was collected from sediment. The sample extraction was carried out using a Zymo Research Extraction Kit and follwed by PCR process using MiFish primers targeting 12S rRNA, then sequencing using Next Generation Sequencing from Illumina Nextseq 500. Sequencing product was analyzed using MiFish Pipeline and followed by abundance and ecological index analysis. The UVC identified 32 species belonging to 10 families in the rainy season and 29 species belonging to 7 families in the dry seasons. The eDNA metabarcoding identified 209 species belonging to 56 families and 27 species belonging to 17 families in the western and eastern seasons, respectively. Based on eDNA metabarcoding data, coral reef fish abundance and community composition differed significantly between seasons (Mann Whitney, p<0.01), while the UVC method did not detect these seasonal differences (Mann Whitney, p>0.05). Based on group category, fish abundance was dominated by major and target fish in west and eastern seasons both using UVC and eDNA. Diveristy indice did not differ significantly between seasons for either method. The Similarity Percentages (SIMPER) analysis was discovered Pomacentrus alexanderae (10.24%) and Abudefduf vaigiensis (44.40%) as highest contribution in western and eastern season using UVC, while Planiliza macrolepis (66.54%) and Plectropomus aerolatus (8.80%) in western and eastern season using eDNA., Ikan terumbu karang merupakan salah satu indikator dalam menilai keanekaragaman hayati di ekosistem tersebut. Keberadaan ikan terumbu karang dapat dipengaruhi oleh faktor antropogenik maupun faktor alam, salah satunya adalah faktor perubahan musim. Beberapa penelitian telah melaporkan bahwa struktur komunitas ikan dapat dipengaruhi oleh variasi musim. Kegiatan monitoring secara musiman sangat penting untuk mendeteksi variasi temporal pada komunitas ikan. Penelitian ini bertujuan untuk mengkaji struktur komunitas ikan terumbu karang berdasarkan musim di Pulau Tidung Kecil dengan menggunakan metabarkoding DNA Lingkungan dan Sensus Visual. Pengamatan secara sensus visual dilakukan dengan luas area 250 m2 , dan sampel air laut diperoleh dari bagian sedimen sebanyak 1 L. Proses ekstraksi sampel dilakukan dengan menggunakan protokol dari Kit Zymo Research, USA dan dilanjutkan dengan proses PCR menggunakan primer MiFish U dengan target lokus 12S rRNA. Sekuensing sampel dilakukan dengan menggunakan Next Generation Sequencing dari Illumina Nextseq 500. Produk sekuensing dianalisis menggunakan perangkat lunak MiFish Pipeline dan dilakukan analisis lebih lanjut mengenai kelimpahan dan indeks ekologi. Penelitian ini berhasil mengidentifikasi 32 spesies pada musim barat dari 10 famili dan 29 spesies dari 7 famili pada musim timur menggunakan UVC, sedangkan eDNA berhasil mendeteksi 209 spesies dari 56 famili pada musim barat dan 27 spesies dari 17
Keyword: Next generation monitoring, Underwater Visual Census, Seasonal Abundance, Reef Fish