Janny D Kusen
Fakultas Perikanan dan Ilmu Kelautan, Universitas Sam Ratulangi, Manado, Sulawesi Utara

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Journal : AQUATIC SCIENCE

Community structure of nudibranchs (Gastropoda) at Coastal Waters of Waleo Village (Mollucas Sea) and Kalasey Village (Manado Bay, Sulawesi Sea) Purba, Aprillawati; Kusen, Janny D; Mamangkey, N Gustaf F
AQUATIC SCIENCE & MANAGEMENT Vol 1, No 1 (2013): April
Publisher : Graduate Program of Sam Ratulangi University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35800/jasm.1.1.2013.1964

Abstract

Nudibranchia are mollusks without a shell. They are simultaneous hermaphrodites and are carnivores while some of them are cannibals. Nudibranchia are frequent occupants and foraging on coral reefs. The study was conducted at two locations, namely Waleo Village Waters representing the waters of Mollucas and Sulawesi Sea was represented by Kalasey Village. The difference in the location of the two waters is expected to affect the existence of community structures. The present study includes diversity, richness, evenness, dominance and similarity. A line transect was used to collect data. We found 84 individuals from both study sites representing 8 species of Nudibranchia, which fall into 4 genera and 3 families namely, Pteraeolididae, Phyllidiidae, and Chromodorididae. The most common family was the Phyllidiidae. The similarity value at both locations was 54.5%© Penelitian tentang struktur komunitas gastropoda nudibranchia telah dilakukan di dua lokasi yaitu Desa Waleo (Laut Maluku) dan Desa Kalasey (Laut Sulawesi). Struktur komunitas yang dikaji meliputi studi keanekaragaman, kekayaan, kemerataan, dominansi dan kesamaan. Metode yang digunakan dalam penelitian adalah line transect. Hasil penelitian menunjukkan, dari kedua lokasi, ditemukan 84 individu yang terdiri dari 8 jenis yang masuk dalam 4 genera dan 3 famili (Pteraeolididae, Phyllidiidae, dan Chromodorididae). Famili Phyllidiidae adalah yang paling umum ditemukan. Nilai kesamaan di kedua lokasi adalah 54,5%©
Community changes of coral reef fishes in Bunaken National Park, North Sulawesi, Indonesia Setiawan, Fakhrizal; Kusen, Janny D; Kaligis, Georis JF
AQUATIC SCIENCE & MANAGEMENT Vol 1, No 2 (2013): Oktober
Publisher : Universitas Sam Ratulangi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35800/jasm.1.2.2013.7273

Abstract

In order to look at changes in coral and reef fish communities during the period of 2006 to 2013, this research was carried out at Bunaken National Park (BNP) with 26 observation sites. The existing data and information of reef fish communities in the park generally could not be used as representative for describing the whole region. Percentage of coral cover and fish abundance during the study period shows that Bunaken Island is more similar to other locations. Reef fish community structure as seen from ecological index (H' at all sites being categorized, E category labile and low category C) shows the condition of the reef fish community is still good. Changes in the structure of reef fish communities showed declining conditions compared to 2006, and coral cover continued to decrease compared to 1998 and 2007. Good overall reef fish and coral cover have decreased; it is thought to be related to the pressure in BNP. Some of the pressures in the region were (i) increasing numbers of domestic as well as foreign visitors, (ii) increasing number of residents in the region, as well as the burden of waste and trash from the Bay of Manado. Penelitian dilakukan di Taman Nasional Bunaken (Utara dan Selatan)   pada 26 lokasi  pengamatan untuk menganalisis perubahan struktur komunitas ikan karang melalui kajian dari suatu time series data dari beberapa penelitian sebelumnya. Data primer mengenai ikan-ikan karang diperoleh melalui visual sensus bawah air yang bersamaan dengan observasi terumbu karang menggunakan point intercept transect. Nilai persentase tutupan karang dan kelimpahan ikan menunjukkan bahwa pada lokasi pengamatan Pulau Bunaken paling baik dibandingan lokasi lainnya. Struktur komunitas ikan karang yang dianalisis dengan indeks ekologi menunjukkan indeks keanekaragaman (H’) di semua site masuk kategori sedang, indeks kesamaan (E) kategori labil dan indeks Dominansi (C) kategori rendah. Hasil penelitian ini menunjukkan bahwa kondisi komunitas ikan karang masih baik, sekalipun  perubahan struktur komunitas ikan karang menunjukkan kondisi yang menurun dibandingkan tahun 2006, begitu juga tutupan karang yang terus turun dibandingkan tahun 1998 dan 2007. Secara keseluruhan baik ikan karang maupun tutupan karang mengalami penurunan, hal ini diduga terkait dengan tekanan yang dialami kawasan TN. Bunaken. Salah satu tekanan terhadap kawasan adalah jumlah turis dari dalam maupun luar negeri yang semakin meningkat tiap tahunnya, penambahan jumlah penduduk di dalam kawasan, serta beban limbah dan sampah dari Teluk Manado.