POLA FLUKTUASI POPULASI BAKTERI DI PERAIRAN PANTAI DAN TELUK PADA SENTRA BUDIDAYA IKAN LAUT DI BALI UTARA

Abstract

Bakteri merupakan mikroorganisme yang secara alami berada dalam ekosistem perairan laut dan beberapa spesiesnya bersifat patogen. Penelitian ini bertujuan untuk menentukan pola fluktuasi populasi bakteri secara umum dan Vibrio spp. secara khusus di perairan pantai dan teluk sebagai dampak dari aktivitas baik panti pembenihan, tambak udang, maupun karamba jaring apung (KJA) di pesisir Bali Utara. Sampel air diperoleh dari tiga lokasi sentra budidaya laut dan satu lokasi ekowisata yang berada di Kecamatan Gerokgak Kabupaten Buleleng. Sampel air diambil dari tiga titik sampling di perairan dengan jarak 50 m, 100 m, dan 300 m dari garis pantai di Desa Gerokgak dan Desa Penyabangan. Sampling air dilakukan pada tiga titik sampling di sekitar KJA di Teluk Kaping, Desa Sumberkima, dan satu titik sampling di perairan dengan jarak 100 m dari garis pantai di Desa Pemuteran. Sampling air dilakukan sekali dalam sebulan dari bulan Februari hingga November 2018. Hasil penelitian menunjukkan bahwa total bakteri dan Vibrio spp. di empat lokasi perairan di Kecamatan Gerokgak, Bali menunjukkan populasi tinggi pada bulan Maret hingga Mei dan menurun pada bulan berikutnya. Dan meningkat kembali pada bulan Oktober hingga November. Total bakteri dan Vibrio spp. tertinggi terjadi di perairan pantai Desa Gerokgak hingga 9.067 ± 7.481 CFU/mL dan 1.147 ± 689 CFU/mL dibandingkan dengan dua lokasi sentra budidaya lainnya (Desa Penyabangan dan Teluk Kaping). Total bakteri dan Vibrio spp. teramati pula di perairan Desa Pemuteran hingga 500 ± 52 CFU/mL dan 65 ± 7 CFU/mL yang kemungkinan merupakan dampak dari aktivitas budidaya ikan. Pola fluktuasi populasi bakteri di perairan pantai Kecamatan Gerokgak, Bali dipengaruhi oleh musim dan kegiatan budidaya perikanan. Tingginya populasi bakteri Vibrio spp. pada perairan pantai dapat memengaruhi kesehatan ikan budidaya.

Bacteria are a group of microorganisms naturally present in aquatic ecosystems. Some of the bacteria are pathogenic to other organisms and cause severe diseases. This study aimed to determine the fluctuation patterns of bacterial populations, with specific interest to Vibrio spp. in coastal and bay areas of North Bali which constantly receive effluents from nearby mariculture activities. Water samples were collected from three locations in a clustered marine fish farming area and one location in an ecotourism area as a control. Water samples were taken from three sampling points in the coastal area of Gerokgak and Penyabangan villages at a distance of 50 m, 100 m, and 300 m from the coastline. Water samples were also collected at three sampling points around floating net cages (KJA) in Kaping Bay, Sumberkima Village, and one sampling point in Pemuteran Village located 100 m from the coastline. Water sampling was carried out each month from February to November 2018. Results of the study showed that total bacteria and Vibrio spp. were notably higher between March-May and October-November. The total bacteria and vibrio reached the peak number at 9,067 ± 7,481 CFU/mL and 1,147 ± 689 CFU/mL, respectively, which occurred in the coastal waters of Gerokgak Village. The total bacteria and Vibrio spp. of up to 500 ± 52 CFU/mL and 65 ± 7 CFU/mL, respectively, were also observed in the waters of Pemuteran Village which are likely to be the effects of aquaculture activities in these of three locations. This study concludes that the fluctuation pattern of bacterial population in the coastal waters of Gerokgak District, Bali is primarily influenced by the season and activities of the fish farming. The high population of Vibrio spp. in the coastal waters could lead to a fish disease oubreak related to the pathogenic bacterium.