Efek Salinitas Berbeda terhadap Respon Fisiologis Benih Ikan Tengadak (Barbonymus schwanenfeldii Bleeker, 1854)

Abstract

Ikan tengadak (Barbonymus schwanenfeldii) merupakan salah satu ikan air tawar asli Indonesia yang memiliki nilai ekonomis yang tinggi. Domestikasi ikan tengadak penting dilakukan untuk tetap menjaga kelestariannya. Dalam domestikasi ikan, salinitas merupakan salah satu parameter yang dapat meningkatkan pertumbuhan dan kelangsungan hidup ikan. Penelitian ini bertujuan menganalisis pengaruh salinitas terhadap kondisi fisiologis benih ikan tengadak (B. schwanenfeldii). Penelitian dilakukan dari bulan Juni hingga Oktober 2021 di Instalasi Riset Plasma Nutfah Perikanan Air Tawar, Kabupaten Bogor. Ikan tengadak diberi perlakuan salinitas 0, 3, 6, 9, dan 12 ppt dan dilakukan pengamatan selama 21 hari. Hasil penelitian menunjukkan bahwa peningkatan salinitas dari 0 ppt mengakibatkan meningkatnya parameter lingkungan (konduktivitas dan alkalinitas), meningkatkan kadar kortisol, dan menurunkan tingkat konsumsi pakan, sintasan, dan laju pertumbuhan benih ikan tengadak. Nilai kortisol dan glukosa paling tinggi pada perlakuan 6 dan 12 ppt. Kelangsungan hidup ikan tengadak paling tinggi terjadi pada perlakuan 0 dan 3 ppt. Benih ikan tengadak memiliki kisaran toleransi yang sempit terhadap salinitas (0-3 ppt). Benih ikan yang dipelihara pada salinitas di atas 3 ppt akan mengalami stres yang terlihat dari tingginya kadar kortisol dan glukosa darah.

Tinfoil barb (Barbonymus schwanenfeldii) is one of the freshwater fish native to Indonesia that has high economic value. Domestication is an important method for the sustainable use of fish species. In fish domestication, salinity is one of the parameters that affect the growth and survival rate of fish. This study aims to analyze the effect of salinity on physiological conditions of tinfoil barb (B. schwanenfeldii) juveniles. The research was conducted from June to October 2021 at the Research Station for Freshwater Fisheries Germplasm, Cijeruk, Bogor. Tinfoil barb juveniles were treated with different salinities including 0, 3, 6, 9, and 12 ppt and observed for 21 days experiment. The research results showed that an increase in salinity from 0 ppt resulted in an increase in environmental parameters (conductivity and alkalinity), increased cortisol levels, and decreased feed consumption, survival rate, and growth rate of tinfoil barb. The highest cortisol and glucose levels occurred in the 12 ppt and 6 ppt treatments. The highest survival rate of tinfoil barb was observed in the treatment of 0 and 3 ppt. This research indicates that the juveniles of tinfoil barb show a narrow tolerant range on salinity (0-3 ppt). The fish fry reared at salinity above 3 ppt experienced stress conditions which can be detected by the high levels of cortisol and blood glucose.