Grouper nursery development in sea floating net cage through the application of Phyllanthus niruri-Allium sativum flour in feed

Untuk mendukung usaha budidaya ikan kerapu kini tengah digalakkan sistem pendederan intensif dalam keramba jaring apung (KJA) di laut. Salah satu cara untuk menjaga kondisi ikan tetap sehat dalam sistem tersebut yaitu dengan pemberian fitofarmaka seperti meniran-bawang putih. Tujuan penelitian ini adalah untuk mengevaluasi penambahan tepung meniran-bawang putih melalui pakan terhadap status kesehatan dan kinerja produksi benih ikan kerapu cantang pada pendederan dalam keramba jaring apung di laut. Benih ikan kerapu cantang (panjang 8.27 ± 0.16 cm dan bobot 10.89 ± 0.83 g) dipelihara dalam KJA berupa waring 1x1x1.5 m3 dan diberi pakan dengan penambahan tepung meniran-bawang putih 20 + 25 g/kg pakan selama 7 hari dan 14 hari pertama pemeliharaan, serta tanpa tepung meniran-bawang putih (kontrol) sebagai perlakuan. Ikan dipelihara selama 42 hari dan disampling setiap 2 minggu untuk diambil darah serta diukur bobot dan panjangnya. Penambahan tepung meniran-bawang putih selama 14 hari pada pakan ikan kerapu dapat meningkatkan status kesehatan dan kinerja produksi. Kata kunci: ikan kerapu cantang, kinerja produksi, meniran-bawang putih, status kesehatan.

A Semi-Analytical Model for Studying Hydroelastic Behaviour of a Cylindrical Net Cage under Wave Action

In the present study, a semi-analytical model based on the small-amplitude wave theory is developed to describe the wave fields around a single gravity-type cylindrical open fish net cage. The cage may be submerged to different depths below the free-water surface. The fish cage net is modelled as a flexible porous membrane, and the deflection of the net chamber is expressed by the transverse vibration equation of strings. The velocity potential is expanded in the form of the Fourier–Bessel series and the unknown coefficients in these series are determined from matching the boundary conditions and the least squares method. The number of terms for the series solution to be used is determined from convergence studies. The model results exhibit significant hydroelastic characteristics of the net cages, including the distribution properties of wave surface, pressure drop at the net interface, structural deflection, and wave loading along the cage height. In addition, the relationships between wave forces on the net cage with hydrodynamic and structural parameters are also revealed. The findings presented herein should be useful to engineers who are designing fish cage systems.

Analysis of the Competitiveness of Floating Net Cage Aquaculture in Indonesia

The purpose of this study is to analyze the competitiveness profile of floating net cage aquaculture in Indonesia. The research was conducted in February – June 2021 at the Directorate General of Aquaculture, Ministry of Marine Affairs and Fisheries of the Republic of Indonesia. The data collection method used in this study is the literature survey method. Primary data in the form of questionnaires with expert judgment respondents as many as 13 people consisting of 11 Lecturers of the Faculty of Fisheries and Marine Sciences, Padjadjaran University, and 2 employees of the Directorate General of Aquaculture, Ministry of Marine Affairs and Fisheries of the Republic of Indonesia regarding the proportion of competitiveness of floating net cage aquaculture fisheries. Secondary data in the form of statistical data on floating net cage aquaculture in 2017 was obtained from the Directorate General of Aquaculture, Ministry of Marine Affairs and Fisheries of the Republic of Indonesia. Data analysis was carried out by using quantitative descriptive analysis. The results showed that Central Java Province which was supported by facilities and infrastructure variables, West Java Province which was supported by human resources and production variables, and North Sulawesi Province which was supported by science and technology variables were in the top three with very high competitiveness category, while the Riau Islands Province and the Bangka Belitung Islands Province are in the bottom two ranks with the low competitiveness category.

"Net cage" technique in the treatment of inferior pole patella fracture: a novel patella internal fixation technique

Objective Fractures of the inferior pole of the patella can cause the knee joint extensor mechanism disorder. The fracture fragments are usually small and comminuted. Therefore, there are certain difficulties in fixation. The purpose of this study is to observe the effect of the "Net cage" technique in the treatment of the inferior pole of the patella. Methods This is a retrospective study that included 16 cases of inferior patella fractures (AO/OTA 34-A1) who underwent the "Net cage" technique from March 2017 to June 2020. Collecting their medical records and follow-up results, measuring indicators include the surgical complications of the fixation method, knee joint function, the number of fluoroscopies, fracture healing, and the incidence of soft tissue stimulation. Results The fractures of all patients healed smoothly, and there were no complications such as failure of internal fixation and fracture of implants. The average number of intraoperative fluoroscopy was 5.56 times (range: 4-10 times); the average fracture healing time was 10.5 weeks (range: 8-14 weeks) ). No patients reported internal fixation-related soft tissue irritation. At the last follow-up, the knee function showed that the average ROM was 133.75° (range: 120°~140°); The average Bostman score was 27.94 points (range: 24-30 points). Conclusion "Net cage" technology for the treatment of inferior pole fractures of the patella has the advantages of reduced fluoroscopy, fixation and stability, early functional exercise, and better knee joints after surgery.

Application of Aeration Injection to Increase Dissolved Oxygen of Surface Water in The Floating Net Cage

Cirata Reservoir is a place for fish cultivators who mostly cultivate tilapia using floating net cages. However, water quality conditions, especially dissolved oxygen levels, which play an important role in tilapia culture in floating net cages are always uncertain and affect the growth of tilapia. Therefore, artificial aeration is needed that is able to increase dissolved oxygen levels so that it is suitable for tilapia culture by using Aearator Dua Lapis (ADL) engine. This study aims to inject dissolved oxygen into the surface layer of the reservoir by applying the ADL engine with gasoline. ADL operated at 1800, 4500, and 5500 rpm with a torque of 3.5 N/m2 and the DO value is recorded every 10 minutes up to 1440 minutes, the results of DO value were recorded and analyzed by using descriptive statistic and statistically using ANOVA with a single factor showed that the rotation has a very significant effect on the resulting DO value (p<0.01). For ADL operation in floating net cages, 4500 rpm rotation was used at certain depth (0.4 m; 1 m; 1.5 m) and the DO value measured at 4.00 am to 2.00 am (22 hours) in aerated floating net cages and without aerated floating net cages.Aerated floating net cages have a higher DO value, especially at a depth of 0.4 m. ADL as an aerator in floating net cages has a very significant effect (p<0.01) in increasing the DO value in floating net cages at a depth of 40 cm to 1.5 m. This proved that the use of ADL is able to increase the DO value in floating net cages in the first layer with a depth of up to 4 m and ADL also can be used as emergency aeration or supplemental aeration for tilapia culture.

Effects of Artifical Substrate on Rearing of Macrobrachium Rosenbergii Post-larvae in Pond Net Cage

Two experiments were carried out to evaluate the effects of addition of net piece substrates in cages for nursery rearing of freshwater prawn, Macrobrachium rosenbergii post-larvae. In the first experiment, net piece substrates were added with an arrangement to increase the surface area of nursery cages to 50% and 75% and compared with cages without any substrate (control). In the second experiment, maintaining surface area increment at 75% in all cages, the net piece substrates were arranged in three different orientations of horizontal, vertical, and 45o angle sloping. Experiments were conducted in a pond of Faculty of Fisheries, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh for a period of 45 days in June –August of 2015 and 2016. A completely randomized design was followed to assign the treatments with three replications. The 75% area increment group showed significantly higher (P < 0.05) growth (1.02 ± 0.09 g) and survival rate (79.43 ± 1.63%), compared to 50% area increment (0.96 ± 0.05 g and 75.03 ± 2.45%) and control group (0.79 ± 0.06 g and 66.66 ± 3.57%). The vertically oriented substrate group showed significantly lower growth 0.95 ± 0.04 g) and survival (76.33 ± 1.15%), compared to the horizontal (1.06 ± 0.05 g and 77.12 ± 1.20%) and sloping (1.16 ± 0.10 g and 79.33 ± 0.57 %) substrate group. However, there were no differences between horizontal and sloping substrate groups regarding final length, final weight, specific growth rate (SGR), and survival rate except food conversion ratio (FCR). The overall results suggested that modification of net cage nursery structure of M. rosenbergii might have significant effects on growth and survival of post-larvae by the manipulation of their behaviour in culture system. Ann. Bangladesh Agric. (2020) 24(2) : 95-106

Analysis of Floating Cage Net Development Trends in West Java Province, Indonesia

This study has the aim to analyze the trend of the development of fisheries floating cage net aquaculture in West Java Province.The research was conducted from September 2020 – July 2021.The method used was a literature survey to determine the development of aquaculture fisheries of floating cage net in regencies and cities in West Java Province. Data collected were analyzed descriptively. Secondary data on Floating Net Cage Aquaculture Fisheries (2004 – 2019) was obtained from the office of Maritime Affairs and Fisheries of West Java Province. The results of this study indicate that the development of aquaculture fisheries of floating cage net in the regencies/cities of West Java Province experienced fluctuating changes which tends to increase from 2004 to 2019.