Korelasi Kualitas Air dan Pertumbuhan Koloni Bakteri dalam Recirculating Aquaculture System (RAS) Ikan Mas Koki (Carassius auratus): Relationship Between Water Quality and Bacterial Colony Development in a Recirculating Aquaculture System (RAS) for Goldfish (Carassius auratus) - Caesar, Nico Rahman; Ramadhan, Nafal Naqi; Djaduk, Saddam Langkung (Water and Marine Pollution Journal: PoluSea, 2025)
Efektivitas Recirculating Aquaculture System (RAS) dalam mengendalikan pertumbuhan bakteri dan menjaga kualitas air sangat penting bagi keberlanjutan budidaya ikan mas koki (Carassius auratus). Penelitian ini bertujuan menganalisis korelasi antara parameter kualitas air dan pertumbuhan koloni bakteri pada kolam pembesaran ikan mas koki dengan dan tanpa penerapan RAS. Perhitungan jumlah bakteri dilakukan menggunakan metode Total Plate Count (TPC), sedangkan parameter kualitas air (suhu, pH, DO, TSS, alkalinitas, amonia, nitrat, dan ortofosfat) diukur secara berkala. Hasil penelitian menunjukkan penurunan signifikan jumlah total bakteri dari 2,1 × 10⁴ CFU/mL pada kolam non-RAS menjadi 0,5 × 10⁴ CFU/mL pada kolam RAS. Pewarnaan gram menunjukkan dominasi bakteri gram-negatif yang berperan dalam siklus nutrien. Kualitas air pada kolam RAS secara umum memenuhi baku mutu, meskipun nilai alkalinitas pada beberapa uji melebihi standar. Analisis Canonical Correspondence Analysis (CCA) memperlihatkan korelasi positif antara total bakteri dengan TSS, pH, fosfat, dan suhu, sedangkan korelasi lemah ditemukan dengan CO₂. Hasil ini membuktikan bahwa RAS meningkatkan stabilitas kualitas air dan menurunkan kepadatan bakteri, sehingga mendukung kesehatan ikan mas koki.   The effectiveness of Recirculating Aquaculture System (RAS) in controlling bacterial growth and maintaining water quality is crucial for sustainable goldfish (Carassius auratus) culture. This study aimed to analyze the correlation between water quality parameters and bacterial colony growth in goldfish grow-out ponds with and without RAS application. Bacterial enumeration was conducted using the Total Plate Count (TPC) method, while water quality parameters (temperature, pH, DO, TSS, alkalinity, ammonia, nitrate, and orthophosphate) were measured periodically. Results indicated that the total bacterial count decreased significantly from 2.1 × 10⁴ CFU/mL in non-RAS ponds to 0.5 × 10⁴ CFU/mL in RAS ponds. Gram staining revealed the dominance of Gram-negative bacteria, which play a role in nutrient cycling. Water quality in RAS ponds generally met aquaculture standards, although alkalinity occasionally exceeded optimal limits. Canonical Correspondence Analysis (CCA) showed positive correlations between bacterial colonies and TSS, pH, phosphate, and temperature, while weak correlations were observed with CO₂. These findings demonstrate that RAS improves water quality stability and reduces bacterial density, contributing to healthier goldfish culture.