Turning Pools in Stepped Fishways: Biological Assessment via Fish Response and CFD Models

With the aim of building more compact fishways and adapting them to field conditions to improve their location by fish, it is common to use turning pools, reducing the longitudinal development of the construction. However, depending on their design, turning pools may affect the hydraulic performance of the fishway and consequently the fish passage. To study these phenomena, turning pools in a vertical slot and in different configurations of submerged notches with bottom orifice fishway types were assessed. Both types of fishways were studied using numerical 3D models via OpenFOAM, a computational fluid dynamics software, in combination with fish responses, assessed with PIT (Passive Integrated Transponder) tag telemetry for three different species of potamodromous cyprinids in several fishways. Results show differences between the hydrodynamics of straight and turning pools, with lower values in the hydrodynamic variables in turning pools. Regarding fish behavior, the ascent was slower in turning pools but with no effect on passage success and without being a problem for fish migration. This information validates the use of turning pools as a key design component for fishways for studied species.

RESPON IKAN DAN HASIL TANGKAPAN BERDASARKAN PERBEDAAN KOMBINASI WARNA CAHAYA LED SEBAGAI ATRAKTOR

Ketertarikan ikan terhadap cahaya telah lama dimanfaatkan sebagai salah satu teknologi dalam penangkapan ikan. Hal tersebut menyebabkan perkembangan pengetahuan tentang hal ini terus dilakukan hingga saat ini. Penelitian ini bertujuan untuk mengetahui respon dan hasil tangkapan ikan terhadap dua kombinasi warna cahaya LED yang berbeda. Kombinasi warna cahaya yang digunakan adalah kombinasi warna biru-merah (BR) dan kombinasi warna putih-merah (WR). Pengambilan data dilakukan pada alat tangkap bagan. Data flux cahaya dan data akustik diambil untuk masing-masing kombinasi. Data bobot hasil tangkapan diambil untuk masing-masing kombinasi warna cahaya. Hasil yang diperoleh menunjukkan bahwa kombinasi cahaya BR sedikit lebih lambat dalam menarik ikan untuk berkumpul, namun ikan di bawah kombinasi cahaya BR dapat bertahan lebih lama dibandingkan ikan di bawah kombinasi cahaya WR. Hasil uji statistik menunjukan bahwa kombinasi cahaya BR memiliki hasil tangkapan yang lebih banyak dibandingkan dengan kombinasi cahaya WR. Namun, perbedaan antara keduanya tidak signifikan.The attraction of fish toward the light has long been used as technology in fishing gear. This led to the development of knowledge about this subject continues to this day. The aim of this research is to study the fish response and catches toward of two differences LED light color combination. One combination was blue-red light color (BR) and the other was white-red light color (WR). Data was collected on lift nets. Data of luminous flux and acoustic taken for each light combination. Data of catched fish taken for each light combination. The result showed that BR combination slightly slower than WR combination in aggregating fish, however BR combination kept fish staying below it in longer time than WR combination. In addition, the results of statics test showed that BR combination had more catched fish than WR combination, although the different between both not significant.

Potential of Telang Plant (Citoria ternatea) for Treatment of Aeromonas hydrophila Infection on Koi Fish (Cyprinus carpio)

The aim of this study was to determine the effective concentration of telang leaf extract for the treatment of koi fish infected by the Aeromonas hydrophila bacteria and find out what clinical symptoms arise from Aeromonas hydrophila infection. The method used in this research was experimental using Completely Randomized Design (CRD) with five treatments and three replications. The treatment given was soaking koi fish infected with Aeromonas hydrophila in telang leaf extract for 48 hours with concentrations of 0, 150, 300, 450 and 600 ppm. Koi fish is infected with A. hydrophila by intramuscular injection of 0.1 ml/head with a bacterial density of 108 cfu/mL. The parameters observed were clinical symptoms including damage to fish body surface, fish response to feed and shock response. The data obtained were analyzed descriptively. The results showed that early clinical symptoms that arise are inflammation that is swelling and reddish color on the injection site and red spots. Other symptoms that occur are ulcers, hemorrhagic & inflammation, discoloration, exopthalmia and dropsy. The use of telang leaf extract with a concentration of 300 ppm was the best and effective treatment for treating the infected koi fish with A. hydrophila because within 9 days, the fish has recovered. It produced the fastest cure rate compared to other treatments.Keywords : Aeromonas hydrophila, koi fish, telang leaf extract, treatment, soaking