Objective: To examine sex reversal both by oral and by immersion using 17α-methyltestosterone on the methyltestosterone residual concentration and the organ histopathology of tilapia fish. Methods: This study used oral and immersion treatment methods for sex reversal of tilapia fish and used normal fish as the control and each treatment was repeated 4 times. 17α-methyltestosterone at dosages of 60 mg/kg feed and 0.5 mg/L were used for oral and immersion methods, respectively. In the first step, tilapia fry were reared at 100 L aquaria, with a density of 1 fish/L for 2 months. In the next step, male tilapias were reared at happa (net cage) of (2×1×1) m³ size in the controlled pond, with a density of 30 fish/happa for 3 months. The methyltestosterone residual concentrations were analyzed by one-way analysis of variance and Duncan’s multiple range tests, while organ histopathology was analyzed by descriptive method. Results: Residual concentrations in the serum of methyltestosterone- treated fish were significantly lower than that in normal fish, especially in 4- and 5-month-old tilapias with averages of less than 5 μg/L, while in normal fish was more than 5 μg/L. In the flesh, methyltestosterone residual concentrations showed relatively no significant differences between the oral and immersion treatment groups and methyltestosterone-treated fish remained lower compared to normal fish, except in 5-month-old tilapia. Methyltestosterone-treated tilapia exhibited histopathological changes on gill, liver, kidneys, and intestine organs. Conclusions: Sex reversal either by oral or by immersion has methyltestosterone residual concentration, but does not exceed the limits (5 μg/L or 5 μg/kg) of synthetic steroid on the fish body, although methyltestosterone causes histopathological changes on gill, liver, kidneys, and intestine.

The COVID-19 outbreak has spread rapidly across the world and has affected health, social, and economic impacts in many countries, including Indonesia. This editorial focuses on the implications of the COVID-19 pandemic on the fisheries sector in Indonesia along with recommendations on how we should deal with the current status. The pandemic has resulted in several negative impacts on the Indonesian community that is directly related to a significant decline in the demand for fisheries products. A range of problems has been reported, including marketing disturbances, issues related to post-harvest and cultivation cycles, and the livelihoods of small-scale fishermen. To overcome these issues, we provide recommendations for various stakeholders to rapidly mobilize the fisheries sector by assisting MSMEs and by helping to market fishery products online, thus facilitating the export of fishery products. These recommendations are expected to stimulate the fisheries sector to mitigate the long-term effects of the COVID-19 outbreak.

The easiest, cheapest, simpliest and efficient polyploidization method was heat shock treatment. Each fish species has different tolerance either initial time, temperature or duration of heat shock. The aim of this study were to show and determine the heat shock effects on differentiation of hatching rate, abnormality, survival rate, and successful polyploidization of common carp. The method that used in this study was experiment. Treatment that used was heat shock 40° C during 1.5 minutes of common carp eggs to 3 and 29 minutes after fertilization. Ten replicates were carried out for each treatment. Parameters test were hatching rate, abnormality, survival rate and polyploidy induction by counting of nucleolus number. Data analysis that used was descriptive. The result of this study indicated that heat shock treatment influenced on hatching rate, abnormality, survival rate and polyploidy induction of the common carp polyploidization. Hatching rate of common carp, triploidy and tetraploidy were 22.63 ± 8.36 percent and 11.10 ± 8.60 percent, abnormality 13.81 ± 4.67 percent and 24.86 ± 8.37 percent, survival rate 52.64 ± 8.46 percent and 55.04 ± 8.15 percent and polyploidy induction 70 ± 7.07 percent and 60 ± 7.07 percent, respectively.