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The present paper deals with the infestation of freshwater fishes Labeo boggut, Oreochromis niloticus, Systomus sarana , and Xenentodon cancila by the parasitic isopods Alitropus typus and Tachaea spongillicola in Tapti, a westward freshwater flowing river of India. The isopods Alitropus typus H. Milne Edwards, 1840 and Tachaea spongillicola Stebbing, 1907 were identified with the taxonomic keys of Milne Edwards (1840) and Stebbing (1907), respectively. It is the first record of the infestation of parasitic isopods Alitropus typus, and Tachaea spongillicola in the freshwater fishes of river Tapti with new hosts’ species Labeo boggut, Oreochromis niloticus , and Systomus sarana .

Taxonomic ambiguity exists in genus Systomus and recently many new species were described under this genus. Systomus sarana subnasutus is considered a valid subspecies of S. sarana sarana although revisions have been done by some researchers. We employed a combination of morpho-meristics and molecular tools (Cytochrome c oxidase I, 16S and Cytochrome b genes of mitochondrial genome) to resolve the two species. Three morpho-meristic characters, head length/maxillary barbel length (HL/MxBL), Lateral Line Scales (LLSs) as well as two truss-based characters, had discernible variation between the two taxa. The sequence analysis (2353 nucleotides) depicted a separate clad of S. sarana subnasutus with high bootstrap support. The findings from combined use of morphology, meristics and mitogenes were concordant. The corroborative results suggest the possibility of two different species. The results suggest to adopt suitable management measures, accordingly.

DNA barcodes analyzed by using relevant techniques provide an imperative approach towards validation of prevailing taxa and putative species. Here, molecular methods were used for assessment of 246 barcodes belonging to 81 fish species from northern Western Ghats of India, using, Barcode gap analysis, barcode index number, automatic barcode gap discovery, Poisson tree processes and general mixed Yule-coalescent, these methods had their potential to discriminate 97.53%, 93.90% 95.06%, 93.82% and 92.59% of species respectively. But, some of them tended to estimate the inconsistent number of species leading to discrepancies between the morphological concept and inference from molecular phylogenetic reconstructions. So, we took a standard approach to recognize those methods that produced consistent results, three of five such methods were identified that revealed three hidden cryptic species complexes in Monopterus indicus, Parambassis ranga and Systomus sarana. Further, to validate these three genetically diverged species, we used diagnostic character based approach along with nine unidentified species through BLOG and WEKAs SMO classifier. Those methods were unable to identify these species, which might be due to the limited number of specimens used for the analysis. This is the first effort to generate the DNA barcode reference library of freshwater fishes from northern Western Ghats of India, one of the world’s biodiversity hotspots. These barcodes when analyzed through the defined workflow, will provide valuable measures to prove the efficiency of molecular species delimitation methods in taxonomic discrimination which aid conservation of biodiversity.

Invasive alien species (IAS) influence the trophic organisation and food web structure in an invaded ecosystem, and therefore, it is imperative to quantify the resultant ecological impacts. The globally recognised ecosystem modelling platform, Ecopath with Ecosim, was used to delineate the impacts of IAS on a tropical freshwater pond ecosystem in India. We analysed the trophic interactions, consumption patterns, prey overlap and mixed trophic impacts of three co-existing invasive alien fish species, African catfish ( Clarias gariepinus ), suckermouth catfish ( Pterygoplichthys pardalis ) and Mozambique tilapia ( Oreochromis mossambicus ), on other functional groups in the ecosystem. Together, the three IAS shared 11% of the total energy consumption and about 50% of the energy consumption by the fish species/groups. There was no predation mortality for African catfish and suckermouth catfish, and a very low estimate for the same was recorded for tilapia (0.64 year −1 ). The IAS shared high mean prey overlap with the native fish groups ( Garra sp., Etroplus suratensis , Systomus sarana , Chanda nama and various small species of the cypriniform genera Puntius , Rasbora and Devario ) indicating a substantial competition between alien and native species in the ecosystem. Consequently, the three IAS exhibited higher mean negative mixed trophic impacts on these functional groups. A very high Finn’s cycling index (39.59%), a low relative ascendency (28.5%) and a very low system robustness (0.07) were observed compared to similar ecosystems, and the baseline values. These indices exposed the vulnerability of the ecosystem towards perturbations, which could be due to the presence of multiple alien invasive species. Mitigating the impacts of IAS should involve a combination of approaches, including eradication through draining and harvesting, high-density stocking of similar trophic level fish in the pond, and local and national level policy interventions.

Background Fisheries have tremendous cultural and educational importance in human societies. The world is undergoing fast environmental and cultural changes, and local knowledge is being lost. Understanding how people interpret environmental change and develop practices in response to such change is essential to comprehend human resource use. This study was planned with the intent to document and conserve the knowledge about the uses of the freshwater fish fauna among the residents in South Punjab, Pakistan. Methods Semi-structured interviews and questionnaires were conducted to collect data from informers ( N  = 88). Principal component analysis, relative frequency citation, fidelity level, relative popularity level, rank-order priority, and similarity index were used to analyze the fish data. Results Overall, a total of 43 species of fishes were utilized in the study region, but only 26 species were utilized ethnomedicinally to treat a variety of illnesses such as asthma, body weakness, burn, chicken pox, cold, cough, eyesight, hepatitis, impotence, joint pain, night blindness, skin burn, spleen treatment, stomach infection, and weakness. The uses of fishes were analyzed employing various indices. The highest use value (UV) of 0.86 was calculated for spotted snakehead ( Channa punctata ), whereas the lowest UV of 0.05 was attained by karail fish ( Securicula gora ). Moreover, Channa punctata , Cyprinus carpio , Labeo rohita , Oreochromis niloticus , Wallago attu , Hypophthalmichthys molitrix , Rita rita , Sperata seenghala , Notopterus notopterus , Labeo dyocheilus , Systomus sarana , Puntius punjabensis , Securicula gora , Ompok bimaculatus , and Ompok pabda were the most popular species with RPL = 1.0. Out of the total, 20 species had a “zero” similarity index, while the ethnomedicinal use of 12 species (i.e., Labeo dyocheilus , Labeo boggut , Systomus sarana , Puntius punjabensis , Aspidoparia morar , Securicula gora , Crossocheilus diplochilus , Mastacembelus armatus , Ompok bimaculatus , Ompok pabda , Labeo gonius , and Sperata seenghala ) was documented for the first time for a variety of diseases (i.e., body weakness, stomach infection, skin burn, joint pain, impotence, asthma, spleen treatment, and chicken pox). Conclusion Our findings showed that the local people of the study area hold noteworthy traditional knowledge about the medicinal and cultural uses of fish species. Furthermore, a comprehensive analysis of active chemicals and in vivo and/or in vitro activities of chemicals derived from ichthyofauna with the highest FC as well as UVs could be interesting for research on new drugs.

Background The present study focuses on the isolation of Bacillus thuringiensis bacterium from the gut of fresh water fish, Systomus sarana, the innovative optimization of culture parameters to produce maximum protease enzyme, by the isolated bacterium, and the elucidation of peptide profile of the protease. And the experimental data and results were authenticated through the response surface method (RSM) and Box-Behnken design (BBD) model. Results During the RSM optimization, the interaction of the highest concentrations (%) of 2.2 maltose, 2.2 beef extract, and 7.0 pH, at 37 °C incubation, yielded a maximum protease enzyme of 245 U/ml by the fish gut-isolated, B. thuringiensis. The spectral analysis of the obtained enzyme revealed the presence of major functional groups at the range of 610-3852 cm.sup.-1viz., alkynes (-C[identical to]C-H: C-H stretch), misc (P-H phosphine sharp), [alpha], [beta]-unsaturated aldehydes, and through PAGE analysis, its molecular weight was determined as 27 kDa. The enzyme's MALDI-TOF/MS analysis revealed the presence of 15 peptides from which the R.YHTVCDPR.L peptide has been found to be a major one. Conclusions The fish gut-isolated bacterium, B. thuringiensis, SS4 exhibited the potential for high protease production under the innovatively optimized culture conditions, and the obtained result provides scope for applications in food and pharmaceutical industries.

Myxozoans are one of the most important groups of microscopic metazoan parasite, infecting freshwater fish both in the wild and in aquaculture. During the twelve months of the study period (between January and December 2018), a total of 240 fish samples, including 60 Labeo rohita , 60 Puntius chola , 60 Pethia ticto and 60 Systomus sarana, were collected from Yezin Dam, Myanmar. Fish samples were examined under a binocular light microscope for the presence of myxosporean parasites. DNA extracted from infected tissues was conducted for PCR targeting small subunit ribosomal DNA (SSU rDNA) genes of myxosporean. The overall parasite infection rate was 48.8% (117/240) and it was highest (22.1%, 53/240) in the rainy season (June–September). In this study, morphological study revealed that five Myxobolus spp. ( Myxobolus sp. 1, 4–6, and 9) and two Thelohanellus spp. ( Thelohanellus sp. 1 and 2) were found to be infected in the gills (gill filaments) and kidneys, four Myxobolus spp. ( Myxobolus sp. 2, 3, 7 and 8) were infected in the gills and one Myxobolus sp. ( Myxobolus sp. 10) was infected in the kidneys of four studied fish species. Among them, three sequences (LC510617, LC510618 and LC510619) were isolated from detected parasites. The obtained sequences were similar (88.1–98.8%) to those derived from myxosporean parasites deposited in GenBank. This is the first report on molecular information about myxosporean parasites in Myanmar.

Indonesian freshwaters are rich in fish biodiversity, one of them is javaen barb. In terms of domestication, it is important to ensure the fish breeding and larval rearing in ex-situ environment. Therefore, studies on artificial spawning are needed to strengthen the information about reproduction of javaen barb in ex-situ environment for domestication and aquaculture purposes. This study aimed to evaluate the reproductive and larval performance in artificially spawned javaen barb within two populations. Broodfish were obtained from West Java (Tasikmalaya and Cianjur population), kept on the fish nets (2×2×1 m) inside the large ponds for two months of adaptation. Broodfish were attached by RFID chips and periodically observed their size and gonad maturity level. Ripen broodfish were artificially spawned. Several reproductive parameters were observed during the experiment, such as egg diameter, fecundity, fertilization rate (FR), hatching rate (HR), and hatching time. Moreover, larval performance was also observed. The results showed that javaen barb successfully spawned with 11 hours of latentcy period. Javaen barb from Tasikmalaya population had a significantly higher fecundity than that of the Cianjur population. Meanwhile, other parameters observed in relation with reproductive and larval performance were not significantly different.

The existence of native fish in Indonesian waters, especially in West Java, is under threat due to environmental damage. The domestication of javaean barb ( Systomus orphoides ) is directed to save the existence of this species and provide economic benefits for the aquaculture community. This study aims were to obtain information about the potential production of larvae and fry of javaean barb that was reared in ex-situ. The parameters observed were fecundity, fertilization rate, hatching rate, the survival rate of larvae, fry growth rate, feed conversion ratio, and fry survival rate. The results showed that javaean barb could be spawned ex-situ through induce breeding techniques. Fecundity was 96 632 ± 24 012 eggs/fish with a fertilization rate of 98.3 ± 1.50% and a hatching rate of 64.5 ± 27.10%. The survival rate of 3 days old larvae was 85.2 ± 7.50%. The growth rate of javaean barb fry was positive allometric. The weight-specific growth rate was 4.9 ± 0.22 % with an FCR of 1.7 ± 0.28 and survival rate of 89.3 ± 4.16%. The success of ex situ javaean barb seedling production opens opportunities for developing this species cultivation in the future.