Background and Aim: Catfish has a high economic value and is popular among consumers. To ensure well-stocked catfish stocks, good fisheries management must also be ensured. The high demand for catfish must be supplemented by preventive measures against pathogenic bacterial infections using probiotics with high potential for Lactobacillus casei and Bacillus subtilis. The aim of this study was to determine the effect of probiotic supplementation consisting of a combination of L. casei and B. subtilis probiotics on the growth, immune system, water quality, proximate value of feed, and body composition of catfish infected with Aeromonas hydrophila. Materials and Methods: This study used a completely randomized study with eight treatments and three replications. The manipulated factor was the probiotic concentration [0% (A), 0.5% (B), 10% (C), and 15% (D)] in groups of catfish infected and uninfected with A. hydrophila. Combination of B. subtilis, and L. casei that were used in a 1:1 ratio of 108 colony forming unit/mL. The study lasted for 42 days. On the 35th day, A. hydrophila was infected by intramuscular injection into fish. The Statistical Package for the Social Sciences (SPSS) software version 23.0 (IBM SPSS Statistics) was used to analyze data on growth, immune system, and water quality. Results: Providing probiotics in feed can increase the nutritional value of feed based on proximate test results. There were significant differences in average daily gain (ADG), feed conversion ratio (FCR), and survival rate (SR) parameters in the group of catfish infected with A. hydrophila (p > 0.05); however, there were no significant differences in final body weight, specific growth rate (SGR), and percentage weight gain. Interleukin-1β (IL-1β) levels were significantly different between treatments C and D. The tumor necrosis factor (TNF) α parameters were significantly different between treatments A and C, whereas the phagocytic activity of treatment A was significantly different from that of treatment D. There was a significant difference (p > 0.05) in the growth parameters of SGR, ADG, and FCR in the group of fish that were not infected with A. hydrophila, with the best treatment being a probiotic concentration of 15%, but there was no significant difference in the SR parameters. IL-1β and TNF-α levels significantly differed between E and E0 (15% probiotics) but were not significantly different in terms of phagocytosis parameters. Conclusion: Based on the results of this study, it can be concluded that using a combination of probiotics L. casei and B. subtilis can improve the growth, immune system, water quality, proximate value of feed, and body composition of catfish infected with A. hydrophila. Keywords: catfish, fish stocks and fisheries management, growth parameters, immune response, probiotic.

Andriyono S, Jobaidul Alam Md, Kim HW. 2019. Environmental DNA (eDNA) metabarcoding: Diversity study around the Pondok Dadap fish landing station, Malang, Indonesia. Biodiversitas 20: 3772-3781. Molecular identification of species is now fast growing and currently widely applied method in the diversity estimation of aquatic biota; even though morphological identification is still carried out. The molecular approach is beneficial complementing on regular surveys, e.g. use of nets, traps, fishing rods, and even with poisons. In this study, the eDNA metabarcoding was applied to water samples around the Pondok Dadap fish landing station, Indonesia to determine the diversity of fish around the waters and also to identify marine fish landed in this area. Molecular identification was carried out on fish samples obtained from the fish market improved GenBank database on COI and ITS. While, seawater samples were carried out by using the next-generation sequencing (NGS) platform to obtain the eDNA metabarcoding data for the first time. Molecular identification obtained 34 species (68 sequences of COI and ITS regions) belonging to 28 genera, 18 families, 4 orders, while the eDNA metabarcoding approach identified 53 marine fish species by using the MiFish pipeline representing 38 genera, 27 families, and 7 orders. From the present study, we can able to estimated fish diversity by eDNA metabarcoding, and this finding will be helpful for baseline data preparation for future effective management of resources in this area.

The global exploration of evolutionary trends in groupers, based on mitogenomes, is currently underway. This research extensively investigates the structure of and variations in Cephalopholis species mitogenomes, along with their phylogenetic relationships, focusing specifically on Cephalopholis taeniops from the Eastern Atlantic Ocean. The generated mitogenome spans 16,572 base pairs and exhibits a gene order analogous to that of the ancestral teleost’s, featuring 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and an AT-rich control region. The mitogenome of C. taeniops displays an AT bias (54.99%), aligning with related species. The majority of PCGs in the mitogenome initiate with the start codon ATG, with the exceptions being COI (GTG) and atp6 (TTG). The relative synonymous codon usage analysis revealed the maximum abundance of leucine, proline, serine, and threonine. The nonsynonymous/synonymous ratios were <1, which indicates a strong negative selection among all PCGs of the Cephalopholis species. In C. taeniops, the prevalent transfer RNAs display conventional cloverleaf secondary structures, except for tRNA-serine (GCT), which lacks a dihydrouracil (DHU) stem. A comparative examination of conserved domains and sequence blocks across various Cephalopholis species indicates noteworthy variations in length and nucleotide diversity. Maximum likelihood, neighbor-joining, and Bayesian phylogenetic analyses, employing the concatenated PCGs and a combination of PCGs + rRNAs, distinctly separate all Cephalopholis species, including C. taeniops. Overall, these findings deepen our understanding of evolutionary relationships among serranid groupers, emphasizing the significance of structural considerations in mitogenomic analyses.

The comple mitogenome of Spanish flag snapper, Lutjanus carponotatus was determined by next generation sequencing (NGS) technique. The mitogenome of L. carponotatus (16,514 bp) habors 37 genes (22 tRNAs, 2 rRNAs, 13 polypeptides) and two non-coding regions, the origin of light strand replication (OL) and the putative control region (D-Loop). Among the 37 genes in L. carponotatus mitogenome, 28 were encoded on the H-strand, whereas only 9 were on the L-strand. Phylogenetic relationship showed that the full mitochondrial genome sequences L. carponotatus was most closely related to Lutjanus russellii with 93% sequence identity clustering with Lutjanus fulviflamma (92%) and Lutjanus vitta (91%).

The introduction of non-native species that have been carried out so far has raised several diverse opinions about the resulting impacts, either positive or negative. As one of the leading commodities in aquaculture, the significant impact of the culture of common carp species (Cyprinus carpio) has been felt by the community. That kind of fish has dominated for both consumption and ornamental fish production in East Java. This type of fish is considered equivalent to other native fish in this region, such as tawes (Puntius javanicus), catfish (Clarias batracus), and gourami (Ospronemus gouramy). However, the problem is if the non-native fish become invasive species in the open waters. When the spread of the non-native fish is out of control, it is feared will break down the food chain and community structure of other native fishes. As Arapaima gigas, the carnivore fish that are not native fish of Indonesia, which have found along the Brantas River, East Java, Indonesia. Rigorous precautions and regulations are needed so that introduced species become species that do not endanger their new habitat by considering ecological, economic, and other impacts. The study of genetic diversity and native species is essential to be done so that the database baseline is accurate and valid.

Plastic is one of the main pollutant sources that are difficult to decompose and then carried into the ocean and fragmented into smaller parts (microplastics) due to UV radiation and water currents. Their small size means that microplastics are often ingested by aquatic organisms, such as fish. This research aimed to determine the presence, abundance, and types of microplastics in the digestive tract of four dominant fishes landed at Lengkong Fish Auction Point, Cilacap, Central Java, i.e. threadfin ( Eleutheronema tetradactylum), mackerel ( Rastrelliger sp.), threadfin bream ( Nemipterus japonicus), and hairtail ( Trichiurus lepturus). We found microplastics in the digestive tract of four selected fishes with a frequency of occurrence of 100%. The concentration of microplastics in fish digestive tracts is relatively high, with a value range of 12 ±2.86 to 28.33 ±8.11 particles∙ind.-1. Microplastics were found in films, fibres, fragments, and granule shape types with various colours: brown, purple, blue, black, green, transparent, and yellow. The polymers found were polystyrene (PS), nylon, acrylonitrile butadiene styrene (ABS), polyurethane (PU), polypropylene (PP), high-density polyethylene (HDPE), and low-density polyethylene (LDPE). The present study provides baseline data for microplastics contamination in commercial fish species landed at Lengkong Fish Auction Point, Cilacap, Central Java, Indonesia. The fact that we discovered PU, the most harmful polymer, piques our attention.