Available online at https://ejournal.undip.ac.id/index.php/pasirlaut Jurnal Pasir Laut Vol. 5 No. 2 : 128-140, September 2021 © Copyright by Jurnal Pasir Laut, p-ISSN 1858-1684, e-ISSN 2747-0776 PENGARUH KONDISI TERUMBU KARANG DENGAN STRUKTUR KOMUNITAS IKAN KARANG DI PULAU KARIMUNJAWA DAN PULAU KEMUJAN, JEPARA, JAWA TENGAH The Effect of Coral Reef Condition with Fish Community Structure in Karimunjawa and Kemujan Island, Jepara, Central Java Muhammad Arkan Zaky Rahman 1 , Norma Afiati 1 , Pujiono Wahyu Purnomo 1 1 Departemen Sumberdaya Akuatik, Fakultas Perikanan dan Ilmu Kelautan, Universitas Diponegoro Jl. Prof. Soedarto, SH, Tembalang, Semarang, Indonesia 50275, Telp/Fax. +6224 7474698 Email : arkanzaky06@gmail.com, normaafiati.na@gmail.com, purnomopoed@gmail.com Diserahkan tanggal: 23 Agustus 2021, Revisi diterima tanggal: 28 September 2021 ABSTRAK Pulau Karimunjawa dan Pulau Kemujan merupakan Kawasan dalam Taman Nasional Karimunjawa (TNKJ) yang memiliki ekosistem terumbu karang berupa reef flat dan reef slope. Kedua pulau ini seringkali dikunjungi wisatawan, sehingga aktivitas tersebut diperkirakan mempengaruhi kualitas perairannya. Penurunan kualitas perairan menyebabkan perubahan struktur komunitas biota, dalam studi ini ikan karang dan terumbu karang. Berdasarkan alur pemikiran tersebut, maka dilakukan penelitian dengan tujuan mengetahui keanekaragaman, kelimpahan serta hubungan ikan karang dan terumbu karang pada daerah reef flat dan reed slope. Pengambilan data dilaksanakan pada bulan Agustus tahun 2020 di perairan Pulau Karimunjawa (Tanjung Gelam dan Legon Lele) dan Pulau Kemujan (Pulau Sintok dan Batulawang), Kabupaten Jepara, Jawa Tengah. Pengamatan terumbu karang dilakukan dengan menggunakan metode UPT (Underwater Photo Transect ) kemudian data diolah menggunakan aplikasi CPCe ( Coral Point Count with Excel ). Pengamatan ikan karang dilakukan menggunakan metode UVC (Underwater Visual Census). Hasil menunjukkan bahwa kelimpahan karang hidup di lokasi penelitian termasuk kategori sedang hingga sangat baik (24%-77,89%). Indeks keanekaragaman tertinggi terumbu karang ditemukan di Pulau Sintok (2,322) dan terendah di Legon Lele (1,815). Indeks keanekaagaman dan kelimpahan ikan karang tertinggi ditemukan di Pulau Sintok (H’ = 3,254 dan 500 ind/150m 2 ) dengan dominasi famili Pomacentridae, sedangkan terendah ditemukan di Tanjung Gelam (H’ = 2,372 dan 123 ind/150m 2 ). Kelimpahan ikan karang dipengaruhi oleh kondisi terumbu karang sebesar 95,83% (R 2 = 0,9583). Semakin baik kondisi terumbu karang, maka semakin tinggi kelimpahan ikannya. Hasil uji anova menunjukkan nilai F hitung = 54,498 dengan tingkat signifikasi sebesar 0,0034 (α<0,05). Hal ini menunjukkan bahwa data signifikan dan hipotesis diterima. Kata Kunci: Karimunjawa, Ikan Karang, Struktur Komunitas, Terumbu Karang ABSTRACT Karimunjawa Island and Kemujan Island are areas within the Karimunjawa National Park which have coral reef ecosystems in the form of reef flats and reef slopes. These two islands are often visited by tourists, so that these activities are thought to affect the quality of waters. The decline in water quality causes changes in structure of biota community. Based on that, research was carried out with aim of knowing the diversity, abundance and relationship of reef fish and coral reefs in reef flat and reed slope areas. Data collection was carried out on August 2020 in Karimunjawa Island (Tanjung Gelam and Legon Lele) and Kemujan Island (Sintok and Batulawang Islands). Coral reefs were observed using UPT (Underwater Photo Transect) method then the data were processed using CPCe (Coral Point Count with Excel) application. Reef fish were observed using UVC (Underwater Visual Census) method. The result showed that condition of live corals in two locations was in medium to very good category (24%-77.89%). The highest diversity index of coral reef was found in Sintok Island (2.322) and the lowest was in Legon Lele (1.815). The highest diversity and abundance index of reef fish was found on Sintok Island (H'=3.254 and 500 ind/150m 2 ) with family domination of Pomacentridae, while the lowest was found in Tanjung Gelam (H'=2.372 and 123 ind/150m 2 ). The abundance of reef fish was influenced by 95.83% (R 2 = 0.9583) condition of coral reefs. The better the condition of coral reefs, the higher the abundance of fish. Anova test result showed F count = 54.498 and significance level of 0.0034 (α <0.05). This showed that the data was significant and hypothesis was accepted. Keywords: Coral Reef, Fish Community Structure, Fish Diversity, Karimunjawa