KEBIASAAN MAKAN DAN TINGKAT TROFIK NILA (Oreochromis niloticus Linnaeus, 1758) DI RAWA JOMBOR KABUPATEN KLATEN

INTAN AMALIA, Dr. Eko Setyobudi, S.Pi., M.Si. ; Dr.Ir. Djumanto,M.Sc.

2017 | Skripsi | S1 MANAJEMEN SUMBER DAYA PERIKANAN

Penelitian ini bertujuan untuk mengetahui kebiasaan makanan dan tingkat trofik ikan nila (Oreochromis niloticus) di Rawa Jombor Kabupaten Klaten. Sampel ikan ditangkap menggunakan jala setiap 2 minggu sekali sebanyak 25 ekor dari bulan Maret hingga Agustus 2016 sehingga jumlah sampel total ikan sebanyak 300 ekor. Setiap sampel ikan diukur panjang total dan bobot individunya kemudian dibedah dan diambil saluran pencernaannya. Panjang saluran pencernaan diukur serta isi lambung diamati dan diidentifikasi jenisnya menggunakan mikroskop. Data dianalisis secara deskriptif meliputi sebaran panjang dan berat, komposisi makanan, frekuensi kejadian, indeks bagian terbesar (IBT), luas relung makanan, tumpang tindih makanan serta tingkat trofik. Hasil penelitian menunjukkan bahwa tumbuhan adalah makanan utama dengan nilai IBT 80,148 % (Ipomoea aquatica, Ottelia alismoides, Alternanthera philoxeroides), detritus sebesar 11,07%, fitoplankton sebesar 8,734% (Nitzschia sp., Synedra sp., dan Chlorella sp.), zooplankton sebesar 0,03%, dan serangga sebesar 0,024%. Kehadiran pakan didominasi oleh tumbuhan (90,08%),detritus (70%), dan Nitzschia sp. (39,15%). Tidak terdapat perubahan jenis makanan seiring pertambahan ukuran ikan nila. Ikan nila jantan lebih beragam jenis makanannya dan persaingannya lebih tinggi dengan luas relung berkisar antara 1,404-1,862 serta tumpang tindih berkisar antara 0,881-0,998. Ikan nila memiliki tingkat trofik 2 hingga 2,004 sehingga tergolong ikan herbivora.

The aims of this research were to know the type of food, food habits and trophic levels of nile tilapia (Oreochromis niloticus) in Rawa Jombor Klaten. Sample of fish were caught using nets every 2 weeks as many as 25 from March to August 2016, so that the total amount of samples was 300. Each sample was measured their total length and weight individual then dissected and taken out his digestive canal. The length of the digestive canal and stomach contents was measured as well as the contents of the stomach, were observed and identified the food under a microscope. Data were analyzed descriptively in term of the length and weight distribution, food composition, frequency of occurance, index of proponderance, niche breadth, food overlapping and trophic level. The index of proponderance was plants of 80.148% (Ipomoea aquatica, Ottelia alismoides, Alternanthera philoxeroides) as the main food, then detritus 11.07%, phytoplankton 8.734% (Nitzschia sp., Synedra sp., and Chlorella sp.), zooplankton 0.03% and insects 0,024%. The presence is dominated feed was composed by plants (90,08%), detritus (70%), and Nitzschia sp. (39,15%). There was no change in the types of food based on its size. Nile Tilapia males more diverse types of food and higher competition with niches breadth ranging from 1.404 to 1.862 and the overlapping food range between 0.881 to 0.998. Nile Tilapia have a trophic level of 2 to 2,004 so classified herbivorous fish.

Kata Kunci : food habits, niche breadth, nile tilapia, Rawa Jombor, trophic levels