DISTRIBUSI DAN KELIMPAHAN LARVA IKAN PADA EKOSISTEM MANGROVE DI DESA PASAR BANGGI KABUPATEN REMBANG

Abstract

ABSTRAK Kabupaten Rembang merupakan salah satu kabupaten yang  terletak di pesisir Pantai utara Jawa Tengah yang mempunyai kawasan rehabilitasi mangrove seluas 106,66 ha. Ekositem mangrove di Kabupaten Rembang telah dikelola oleh masyarakat dan LSM setempat untuk dijadikan kawasan wisata dan masyarakat juga membuka lahan tambak yang dapat memberi tekanan bagi fungsi ekologis mangrove. Salah satu dampak yang sangat dikhawatirkan adalah terganggunya habitat vital serta perkembangan larva ikan di area asuhan hutan mangrove. Tujuan penelitian ini adalah mengetahui jenis famili larva ikan, distribusi, kelimpahan, keseragaman, keanekaragaman dan dominasi larva ikan di ekosistem mangrove di Desa Pasar Banggi Kabupaten Rembang. Penelitian ini dilakukan pada bulan April 2016. Pengambilan sampel dilakukan sebanyak tiga kali, dengan interval waktu 1 minggu sekali. Penelitian ini menggunakan metode survei sedangkan pengambilan sampel dilakukan dengan metode stratified sampling. Hasil penelitian didapatkan larva ikan dari tujuh famili, yaitu: Gerreidae, Gobiidae, Clupeidae, Engraulidae, Adrianichtyidae, Megalopidae dan Carangidae. Indeks keanekaragaman berkisar antara 0,087- 0,770, dengan nilai tertinggi di wilayah mangrove umur sekitar tiga  tahun. Indeks keseragaman berkisar antara 0,062 – 0,555, nilai tertinggi juga pada wilayah umur mangrove sekitar tiga tahun. Nilai indeks dominasi berkisar antara 0,577 – 0,972, dengan nilai tertinggi pada wilayah mangrove berumur lima puluh tahun. Kelimpahan tertinggi larva ikan yang tertangkap pada lokasi penelitian didapat pada wilayah A (wilayah mangrove berumur sekitar lima puluh tahun) adalah sebesar 40 Ind/m3, wilayah B (wilayah mangrove berumur sekitar tujuh tahun) sebesar 22 Ind/m3 dan yang terendah adalah wilayah C (wilayah mangrove berumur sekitar tiga tahun) sebesar 19 Ind/m3..                      Kata Kunci : Kelimpahan Larva Ikan; Mangrove; Kabupaten Rembang ABSTRACT Rembang Regency located in the northeastern part of Central Java which has 106.66 ha mangrove rehabilitation area. Mangrove ecosystem in Rembang has been managed by local communities and NGOs for eco-tourism. The local people also have actively cleared mangrove area for artificial ponds that are put an ecological pressure into mangrove ecosystem function.  One of the important impact that needs to be concerned is the disruption of vital habitat as well as the development of fish larvae in mangrove area. The purpose of this study was to determine the type of fish larvae families, distribution, abundance, uniformity, diversity and dominance of larval fish in in the mangrove ecosystem of Pasar Banggi, Rembang. The samplings were conducted in April 2016 three times, with intervals one week. The sampling method was done by stratified sampling method. In three times sampling we obtained seven families of fish larvae in the following name: Gerreidae, Gobiidae, Clupeidae, Engraulidae, Adrianichtyidae, Megalopidae and Carangidae. The diversity indices range between 0,087- 0,770, with the highest in level in mangrove area with mangrove age of three years. The uniformity index ranges between 0,062 – 0,555, the highest value is also in mangrove area with mangrove age of three years. The dominance index values ranging between 0,577 – 0,972, with the highest value in the in mangrove area with mangrove age of fifty years. Highest abundance of fish larvae were caught among the sites acquired in the area A ( mangrove area about fifty years ) is 40 Ind / m3 , region B ( mangrove area about seven years ) of 22 Ind / m3 and the lowest is the area C ( mangrove area about three years old ) by 19 Ind / m3 .Key Words: Fish Larva Abundance, Mangrove , Rembang District