Kukuh Nirmala

Water quality fluctuations under floating net cages for fish culture in Lake Cirata and its impact on fish survival

Vertical profiles of water quality were surveyed before and after mass mortality of fish cultured in cages in Lake Cirata, a man made lake in Indonesia. The first survey was performed 4 months before the mass mortality and the second survey was carried out 4 days after the mass mortality. In the first survey, the conditions below 8 m depth were reductive and anoxic, although at 8 and 10 m depth, the water became oxidative in spite of low oxygen concentration in the second survey. These changes were probably caused by strong mixing of surface water with deeper water. Eight months after the mass mortality, when the redox potential at 8m became reductive again, exposure tests of fish were performed in different layers in the water column around the cage. During the exposure tests the redox potential of the water was less than −100 mV and 93% of carp died within 6 h of exposure at 8 m depth. These results indicated that the mass mortality was caused by the strong mixing of surface water with reductive water in deeper layers.

Accumulation of tributyltin (TBT) in the blood of flounder and dab intraperitoneally administered with TBT

Abstract The present study was carried out to investigate the accumulation of TBT in the blood of cultured Japanese flounder, Paralichthys olivaceus, and dab, Limanda yokohamae. TBT-CI was intraperitoneally administered to fish at a dose of 2.5mg kg−1 b.w. At 2, 4, 6 and 8 days after the injection, the blood, liver, kidney, spleen and dorsal muscle were collected. The amounts of TBT within the tissues were determined by GC-FPD. High TBT concentrations were found in the serum of Japanese flounder, levels which corresponded to 22~37-fold those found in the muscle, and 7~12-fold those found in the liver. High TBT concentrations were also found in the serum of dab. The results of gel filtration of the serum showed that TBT was bound to an unknown substance (mol. wt ca 50000).

LAJU PENYERAPAN INSEKTISIDA TRIKLORFON PADA UDANG WINDU (Penaeus monodon)

Penelitian ini bertujuan untuk mengetahui laju penyerapan dan rasio biokonsentrasi insektisida triklorfon dalam tubuh udang windu pada tingkat konsentrasi pemaparan yang berbeda. Penelitian dilakukan dalam skala laboratorium dengan Rancangan Acak Lengkap menggunakan akuarium. Bahan uji yang digunakan adalah formulasi insektisida triklorfon serta hewan uji adalah pasca larva udang windu. Perlakuan adalah tingkatan pemaparan insektisida triklorfon, yaitu 0,0037 mg/L; 0,0110 mg/L; dan 0,0183 mg/L dalam air laut bersalinitas 20 ppt. Analisis residu triklorfon dalam sampel udang windu dan air diekstraksi, kemudian diidentifikasi menggunakan kromatografi gas cairan. Hasil penelitian menunjukkan bahwa laju penyerapan insektisida triklorfon oleh udang windu pada perlakuan 0,0110 mg/L dan 0,0183 mg/L tidak berbeda nyata tetapi keduanya berbeda dengan perlakuan 0,0037 mg/L. Laju penyerapan secara berurutan sebesar 0,0049 mg/kg/jam; 0,0088 mg/kg/jam, dan 0,0086 mg/kg/jam masing-masing pada perlakuan 0,0037 mg/L; 0,0110 mg/L, dan 0,0183 mg/L. Rasio biokonsentrasi triklorfon dalam tubuh udang windu semakin kecil dengan meningkatnya konsentrasi triklorfon, yaitu dengan nilai 2,4545; 1,6132; dan 1,3373 masing-masing pada perlakuan 0,0037 mg/L: 0,0110 mg/L, dan 0,0183 mg/L. The experiment aimed to study the uptake and bioconcentration ratio of trichlorfon insecticide in tiger prawn at different exposure concentration. The study was conducted using the aquarium in the laboratory condition. Test material is trichlorfon insecticide and test animal is post larvae of tiger prawn. Treatments were 0.0037 mg/L, 0.0110 mg/L, and 0.0183 mg/L of trichlorfon insecticide by dissolved in water on 20 ppt. Shrimp and water sample were extracted then identified liquid gas chromatography. The results of the experiment shohwed that uptake of trichlorfon insecticide is not different at 0.0110 mg/L and 0.0183 mg/L and both are different with 0.0037 mg/L with the uptake rate are 0.0049, 0.0088 and 0.0086 mg/kg/h at 0.0037 mg/L, 0.0110 mg/L, and 0.0183 mg/L, respectively. Bioconcentration ratio of trichlorfon in tiger prawn were decreasing while treatment concentration was increasing, that are 2.4545, 1.6132, and 1.3373 at the treatment 0.0037 mg/L, 0.0110 mg/L, 0.0183 mg/L, respectively.