Sand crab (Emerita sp.) is a marine biodiversity, but it has not been used as a fish feed ingredient. This study aimed to evaluate the nutritional value of sand crabs and to understand its effect when used as feed ingredient on the performance of Koi carp. The study was conducted in two steps, which is evaluation of the nutritional value of sand crab and its effect on fish performance. The proximate composition, amino acids, and fatty acids were measured using AOAC methods, and then the carotenoid content was determined by spectrophotometry. In the second step, the sand crab was added to fish feed at doses of 0, 5, 10, and 15 percent, and fed to koi fish for 42 days. The parameters observed were length gain (LG), weight gain (WG), and feed efficiency (FE). Nutritional data were analyzed by description and compared with fish feed ingredients from previous studies. Fish performance were analyzed by one-way ANOVA. When significant, Tukey’s significant mean test was applied. The result showed that the nutritional value of sand crab was comparable to other feed ingredients with a protein content of 37.88%, while carotenoid content was superior. The best performance of Koi carp was obtained with a dose of 15% sand crab in the diet, with LG, WG, and FE values of 0.93 ± 0.05 cm, 0.48 ± 0.06 g, and 63.50 ± 7.05 %, respectively. Based on this result, it can be concluded that sand crab has a high nutritional value and can be used up to 15% in Koi carp diet.

Pongok Island possesses small islands surrounded by waters with some primary commodities of sea farming. Seeking appropriate locations for marine aquaculture is a careful planning step to acquire optimal results. The sustainability of sea farming areas should be set based on considering species for easy implementation. This research aimed to analyse the area's suitability for aquaculture activities of seaweed cultivation, rearing groupers, and lobsters in floating net cages, and pearl oyster farming. This research occurred from June to November 2022 in Pongok Islands, South Bangka Regency, Indonesia. The method used in this research consisted of parameters weighting and scoring for cultivating seaweeds, groupers, or lobsters utilizing floating net cages and pearl oysters. Sea water samples analysis was processed in the Marine Science Laboratory of Bangka Belitung University and PT Global Quality Analytical, Bogor – West Java. Collected data were then scaled based on expert justification of scaling priority on aquaculture suitability. The mapping area of sea farming locations based on potential resources was then determined using map software. This research indicates that cultivating seaweeds is recommended to be established in two stations, 1 (149.79 ha) and 2 (186.46 ha), that are very suitable (S1) and the suitable (S2) categories, respectively. Station 3 (325.41 ha) and 4 (4.11 ha) are grouped into very suitable (S1) categories for pearl oysters and groupers or lobsters using floating net cages, respectively. The total estimate for sea farming in the waters of Pongok Island is 665.77 ha. Allocating seawater spaces should be assigned for sustainable fishery management. Maps of area suitability for sea farming can obviate conflicts in seawater areas.

The main objective of this research is to study the possibility of using endophytic bacteria isolated from some medicinal plants (onion, Allium cepa, brassicales, Salvadora persica, and fenugreek, Trigonella foenum-graecum) as probiotics for Nile tilapia (Oreochromis niloticus). Fish growth was evaluated using fish growth performance indices and approximate fish composition. Fish health was assessed by quantifying some biochemical compounds in fish serum, and at the end of the experiment, a challenge test was performed with Vibrio parahaemolyticus. The use of endophytic bacteria increased all indicators of growth performance compared to the control group. Endophytic bacteria of Fenugreek recorded higher growth performance than other plants. Moreover, in all treatments except for onion, bacteria mixed with feed significantly increased in fish growth performance compared to bacteria added to rearing water. Endophytic bacteria of onion and fenugreek recorded higher concentrations of protein in muscles than the control group by 56 and 49%, respectively. Furthermore, 88, 75 and 63% of the treatments recorded a decrease in albumin, ALT and AST concentration compared to the control group. Although the concentration of urea in the blood was higher than the control group by about 7.4 to 44.3%, but the challenge test showed that all treatments had a 20% mortality rate compared to the control group (10%). As a result, the endophytic bacteria of onion, brassicales and fenugreek can be used as probiotics for Nile tilapia. Further study is needed to elucidate the optimal bacterial concentration necessary for tilapia growth.

The present study was conducted to investigate the development of Panulirus ornatus and P. homarus puerulus larvae into juveniles in a captive environment. Pueruli were collected from the local fishermen and transported by air to the research facilities. Puerulus of each species were stocked into 3 floating plastic compartments (5 cm × 12 cm × 17 cm) with sufficient holes, aeration, and a filtration system until reached their first moulting. Results indicated that both puerulus species were completely moulted after 6 days of stocking with the survival rate of 100% and 93.3%. Moulting began on Day 5 for P. ornatus and Day 4 for P. homarus pueruli. The weight of P. ornatus increased significantly after the metamorphosis (P<0.05). The initial and final weights of P. ornatus were significantly greater than P. homarus (P<0.05). In addition, the total and carapace lengths of both species were significantly increased (P<0.05). Morphological observations indicated that there was a significant distinguishing feature such as the antenae form and body pattern colour of both species. In conclusion, proper handling of the pueruli according to each species is required to preserve the quality in order to achieve greater success in metamorphosis into juveniles.

Tinfoil barb, Barbonymus schwanenfeldii (Bleeker, 1854), is a potential freshwater fish for Indonesian aquaculture. Before widely used, the candidate needs to be evaluated. This research aimed to evaluate the reproductive performance of the first generation (G1) and larval performance of the second generation (G2) of domesticated tinfoil barb. A total of 68 female and 24 male broodstocks were selected for the artificial breeding program. The gonadal maturity test was carried out by canulating the eggs every month. Before spawning, GnRHa hormone was injected into the dorsal area (0.5 mL/kg for female and 0.2 mL/kg for male). Fecundity, fertility rate, hatching rate, embryogenesis, and larvae ontogeny were recorded. The results showed that the first matured G1 males of tinfoil barb were at the standard length of 16.01 ± 1.18 cm, while females at 15.79 ± 1.23 cm. The mature broodstock indicated by the gonad maturity stage III and IV confirming higher estradiol concentration (above 400 pg mL-1). The fecundity of two mature broodstock-sized of 217.2 g and 197.3 g were 12,495 and 15,782 eggs, respectively. The spawning season of G1 tinfoil barb was in October and November (rainy seasons). The fertilized eggs latency time was 10 hours 44 minutes at 25°C and hatched after 23 hours 7 minutes. The fertility rate was 96.96 % and the hatching rate was 95.16 %. The survival rate of G2 normal larvae was 100 % at three days of the rearing period. The G2 larvae production in this experiment provides an excellent opportunity for fish diversification both for aquaculture and restocking.

Gram-positive spore bacteria are widely used as probiotics in general sectors. However, there are still limited bacterial isolates as probiotic candidates available from indigenous isolates, especially in aquaculture. This study aimed to obtain potential spore-forming isolates as probiotic candidate for tilapia. Tilapia fish samples were collected from Sukabumi, Ciamis, Serang, and Papua. Bacterial isolates were isolated from the digestive tract of tilapia. Bacteria were identified based on their morphological, molecular characteristics, complete genome composition, and cell surface identification based on hydrophobic properties. In this study, six bacteria were isolated and identified by molecular characteristics using 16S rRNA sequences. Based on the phylogenetic analysis, the 9 PP isolate was Priestia megaterium basonym: Bacillus megaterium, CMS 16N isolate was Brevibacillus halotolerans, PPN 10 isolate was Bacillus sp., 3.1 SKBM isolate was Bacillus mycoides, CMS 22 N and SRG32 isolate were Bacillus subtilis. Six bacteria had different phenotypicals, ATGC sequence compositions, and a higher proportion of total G~C sequence composition above 50%. The coherent cell surface hydrophobicity test was positive on the SAT, SA, AA, and compact growth patterns in soft-agar media for 9 PP, CMS 22 N, and SRG32 isolates. From our study, the indigenous spore-forming bacteria isolated from tilapia stomachs are enzymatic bacteria, which have a strong attachment to host tissue and high potential as a probiotic candidate for fish. Various hydrophobicity test results from each isolate indicate that the protein composition in the cell surface is different.

Javaen barb is a native fish in Indonesian inland water with economic value and the potential to be developed as cultured fish resources and ornamental commodities. In the development of aquaculture, there are still problems, such as the low adaptability of the larvae, so that their survival is also low. This study was conducted to evaluate the effect of melatonin supplementation on the productivity of Javaen barb fish juveniles in culture containers. This study was conducted experimentally using a completely randomized design consisting of four treatments with different doses of melatonin supplementation, i.e., A) control (without melatonin supplementation), B) 0.2 mg/100 g of feed, C) 0.4 mg/100 g feed, and D) 0.6 mg/100 g feed, each treatment was repeated three times. Javaen barb juveniles were kept in an aquarium measuring 30×36×60 cm with a water level of 40 cm, consisting of 12 units. Each aquarium was stocked with 150 individuals and given an aeration system with the same air pressure intensity. Feeding was carried out ad-libitum with a frequency of three times daily for 180 days of rearing. The results showed that melatonin supplementation of as much as 0.6 mg/100 g of feed was able to increase the growth of Javaen barb fish juvenile with the highest survival rate (81.33 ± 0.54 %) and feed conversion ratio (2.61 ± 0.14). Melatonin supplementation of 0.6 mg/100 g of feed had higher total leukocyte (3.41±0.73×104 cells/mm3) and hemoglobin (5.07±0.12 g%) values and provided the best production performance in Javaen barb juveniles.

This study aimed to investigate the suitability of black soldier fly larvae (BSFL) combined with a commercial diet (CMD) on growth and feed performances of hybrid catfish (Clarias gariepinus x C. macrocephalus). A completedly randomized design was used to consist of four treatments and three replications with 100:0 (control), 75:25, 50:50, and 25:75 of CMD and fresh BSFL blended feeding. Fish were reared in 2 m2 inland canvas cages for 60 days. The results indicated that fish were fed 100% CMD had better average weight gain (AWG), daily weight gain (DWG), specific growth rate (SGR), food conversion ratio (FCR), feed efficiency (FE), and survival rate (SR) than the other treatments, but there was no statistically significant difference (p>0.05) when compared to 75:25 and 50:50 CMD:BSFL feeding. At the end of the experiment, the SR of fish was 81-91% and showed no significant difference (p>0.05) when compared between treatments. Therefore, hybrid catfish rearing can compensate CMD by fresh BSFL up to 50% of the feed amount per day. However, feeding with fresh BSFL can have side effects concerning steatosis

The multiple-pathogen infection causes severe economic impact to shrimp industry in Indonesia and worldwide due to mass mortality and multiple abnormalities of the survived infected shrimps. However, multiple-pathogen detection tools in shrimp diseases have not yet widely used. The purpose in this study was to develop and applied simultaneous detection system using multiplex polymerase chain reaction (PCR) assay from natural infections caused by white spot syndrome virus (WSSV), infectious hypodermal and haematopoietic necrosis virus (IHHNV) and monodon baculovirus (MBV) in Black tiger shrimp culture. To analyze multiple-pathogen infections in the shrimp, the study designed and used three pairs of specific primers targeting DNA virus from the shrimp diseases. All amplifications used a specific master mix for multiplex PCR assay and standardized extracted nucleic acid from the samples. This mPCR assay successfully amplified the DNA of three viruses in a single tube-run by multiplex PCR for each virus. Based on the results, the study confirms that multiple-pathogen infection contributes the highest mass mortality rather than from single infection by either WSSV, IHHNV or MBV. This study also confirms that the mPCR assay is a faster, cheaper, and efficient method to detect and subsequently prevent the spreading of multi-pathogen shrimp diseases.

The research of the effect of gibberellic (0.4 - 3.8x 10-8 mol.L-1) and salicylic (0.4 - 3.8 x 10-5 mol.L-1) acids, in a wide range of their concentrations, on the growth indicators and biochemical composition of the cumulative culture of the microalgae Phaeodactylum tricornutum was carried out. It was determined that salicylic acid in a concentration of 0.4 x 10-5 mol stimulated cell growth by 184.6%, and gibberellic acid at a concentration of 0.39 x 10-8 mol by 181%, compared to the control. The effect of gibberellic acid during the experiment was expressed in the inhibition of protein accumulation in the culture, compared with the control. The use of salicylic acid led to a greater accumulation of protein in the culture than when using gibberellic acid. It was shown that salicylic acid had a positive effect on the accumulation of carbohydrates on day 9 and gibberellic acid on day 14 of culture. Gibberellic acid had no effect on the accumulation of lipids in the culture of microalgae. Under the action of salicylic acid for 14 days of cultivation, the lipid content increased by 18.5%, compared with the control. There were no quantitative differences in the content of chlorophyll when using two phytohormones. In this study, the optimal concentrations of gibberellic and salicylic acids for linear growth rate and the highest production of protein and carbohydrates for Phaeodactylum tricornutum were determined. Position, depending on the stage of microalgae growth, is noted.