Judul: (Partitioning Diet Intra and Inter-Spesific Competition of Two Kerapus (Epinephelus malabaricus And Epinephelus areolatus) Using DNA Metabarcoding)
Abstrak: Ikan Kerapu (Subfamily: Epinephelinae) merupakan predator tingkat tinggi (top predator) dalam ekosistem terumbu karang. Secara ekologi, ikan dari famili ini sangat penting dalam jejaring makanan di ekosistem terumbu karang, terutama di wilayah Raja Ampat. Penelitian ini dilakukan untuk menganalisis komposisi makanan dan kompetisi intra-dan inter spesifik antar dua spesies Serranidae (Epinephelus malabaricus dan Epinephelus areolatus) di Waisai, Kepulauan Raja Ampat. Pengambilan sampel dilakukan pada bulan Januari 2018 di tempat pendaratan ikan Waisai. Selanjutnya ekstraksi DNA dilakukan di Laboratorium BIODIVSI-Institut Pertanian Bogor. Amplifikasi DNA menggunakan primer COI Mitokondrial. Sekuensing DNA dilakukan di University of Rhode Island, Amerika Serikat. Kemudian data sekuensing didapatkan dan kemudian dianalisis menggunakan software QIIME2. Analisis statistik menggunakan software R dengan menggunakan paket Vegan dengan fungsi ggplot dan METAMDS. Analisis ini bertujuan untuk menentukan keragaman β berdasarkan indeks Shannon dan Simpson. Hasil menunjukkan komposisi makanan ikan kerapu terdiri atas 13 spesies dengan 8 famili yaitu Chanidae, Apogonidae, Serranidae, Scianidae, Holocentridae, Opleghnatidae, Lateolabracidae, Blennidae and satu spesiies yang tidak teridentifikasi (unindentified species). Penelitian ini menunjukkan bahwa keragaman komposisi makanan pada ikan Epinephelus malabaricus lebih bervariasi daripada Epinephelus areolatus. Famili Scianidae mendominasi komposisi makanan di antara kedua spesies. Tidak terjadi persaingan interspesifik antara Epinephelus malabaricus dan Epinephelus areolatus. Hal ini disebabkan karena variasi jenis makanan pada Epinephelus areolatus lebih rendah daripada Epinephelus malabaricus. Sedangkan antar Epinephelus malabaricus berpotensi terjadinya kompetisi intraspesifik dan relung dalam ekosistem ikan tersebut., Kerapus (Subfamily: Epinephelinae) as the family Serranidae were known as top predators within the coral reef ecosystem. Ecologically, this family is one of the most important component in the food webs of the coral reef ecosystem, as in Raja Ampat. This study was conducted to investigate the food composition and as well as the inter and intra-specific competition of the two Serranidae species (Epinephelus malabaricus and Epinephelus areolatus) in Waisai, Raja Ampat. Data was collected in January 2018 at the fishlanding site in Waisai. Amplification of DNA was using the COI mithocondrial primer. Analysis were using the Software of QIIME 2 and R for statistical analysis by Vegan package with the ggplot and METAMDS function. Statistical analysis exhibiting of Shannon indices, Simpson indices and significance test used Permanova. Results showed that the total composition of fish food consists of 13 species (8 families), which were Chanidae, Apogonidae, Serranidae, Scianidae, Holocentridae, Opleghnatidae, Lateolabracidae, Blennidae and 1 unindentified species. The results showed a dissimilar diversity of food composition in both species of fish. Epinephelus malabaricus resulted the more variety of food composition than in Epinephelus areolatus. The Scianidae family was identified as the higher abundancy than other families in the food composition. There were not occurred interspecific competition between Epinephelus areolatus and Epinephelus malabaricus species, regarding to variations of the type of food feeding kerapu Epinephelus areolatus lower than Epinephelus malabaricus. On the contrary, there was an intracspesific competition in Epinephelus malabaricus species to the occurrence of niches in ecosystem.
Keyword: DNA metabarcoding, food composition, serranids, trophic level