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Catch and consumption of torpedo scad (Megalaspis cordyla) over the western Indian Ocean, but also the western Pacific from Japan to Australia is constantly increasing. Taking into account the degree of exploitation and missing information on the population structure of torpedo scad stocks it is crucial to provide population data. The analysis included individuals obtained in 2012 and 2013 from local markets in Madagascar, Tanzania, Vietnam and Cambodia and after successful DNA extraction fragment of the nuclear rhodopsin gene (RH1) and 9 microsatellite regions (SSRs) were amplified and analysed. Based on the obtained results it was found that there was no 100% overlap between the compared RH1 sequences and those from GenBank. In the case of the studied SSRs, the results allowed the initial characterisation and assessment of the genetic diversity of populations. Moreover, population assignment test distinguished the studied populations into two geographically distant subpopulations.

Hybrids of koi, Cyprinus carpio x crucian carp, Carassius carassius and koi x goldfish, Carassius auratus, proved to be susceptible to koi herpesvirus (KHV, syn. CyHV-3) and developed KHV disease (KHVD). While hybrids of koi x goldfish were partly resistant to mortality following infection by immersion, most koi x crucian carp hybrids died after bath infection. KHV DNA was detected in dead fish but also in all surviving animals by different polymerase chain reactions (PCRs). According to these results, hybrid crossbreeding does not seem to prevent severe losses associated with KHV in terms of inducing KHVD. The present study showed severe losses after a waterborne KHV infection of between 35% and 100% in koi x goldfish and koi x crucian carp hybrids as well as in SPF carp.

Background. The study is a contribution to Project CELFISH which involves genetic identification of populations of fish species presenting a particular economic importance or having a potential to be used in the so-called commercial substitutions. The EU fish trade has been showing a distinct trend of more and more fish species previously unknown to consumers being placed on the market. Molecular assays have become the only way with which to verify the reliability of exporters. This paper is aimed at pinpointing genetic markers with which to label and differentiate between two populations of splendid alfonsino, Beryx splendens Lowe, 1834, a species highly attractive to consumers in Asia and Oceania due to the meat taste and low fat content. Materials and methods. DNA was isolated from fragments of fins collected at local markets in Japan (MJ) (n = 10) and New Zealand (MNZ) (n = 18). The rhodopsin gene (RH1) fragment and 16 microsatellite DNA fragments (SSR) were analysed in all the individuals. The sequences obtained were processed using the BioEdit and BLAST software, whereas SSR data were processed with the GeAlEX analysis package. Results. The BioEdit software-aided comparison of MJ and MNZ nucleotide sequences of the rhodopsin gene fragments were identical and showed 100% agreement with the alfonsino sequence deposited under access number DQ197832. The preliminary analysis of SSR markers showed all the loci analysed in both populations to be polymorphic, and when randomly selected specimens were assigned to the original populations. The affinity test correctly identified the provenance of all those specimens. Conclusion. The results obtained constitute a tool for molecular differentiation between alfonsino populations collected in the FAO 81 (New Zealand) and FAO 71 (Japan) areas for the purpose of catch quota control and for checking the agreement between the label declaration and the actual product.

Background. Monitoring the genetic diversity of fish populations can provide information necessary to determine fishing quotas for the commercially caught species. One of the species subjected to intensive exploitation is the yellowstripe scad, Selaroides leptolepis (Cuvier, 1833), commonly occurring in the coastal waters of Vietnam, Cambodia, Malaysia, and Indonesia. This paper is the third part of a larger project: ”Development of a genetic-based system for identification of food products from fisheries and aquaculture introduced to the European Union customs area”. Materials and methods. Fin fragments of the yellowstripe scad, Selaroides leptolepis, were obtained in 2012 and 2013 from local markets in Vietnam (SVN), Cambodia (SKH), Malaysia (MMY), and Indonesia (MID). The analyses focused on the amplification and sequencing of a fragment of the nuclear rhodopsin gene which utilized as identification label. Subsequently, in the obtained SVN, SKH, MMY, and MID samples, 11 microsatellite regions (SRR) were analysed. Sequence analyses were performed using the BioEdit and BLAST software, while the analysis of the obtained SRR data was conducted using the GenAlEx software. Results. The analysis of the obtained loci variants divided the investigated populations into two genetically homogeneous groups: the Vietnamese–Indonesian group and the Malaysian–Cambodian group. The analysis of genetic diversity revealed statistically significant deviations from the Hardy–Weinberg equilibrium in the investigated populations and indicated the Vietnamese population as the most stable, while the Malaysian population as the least stable. Conclusion. The study provides information on the genetic diversity of the investigated populations and allows assignment of the captured fish to the geographical regions specified. Moreover, indicate that among analysed populations the safest populations were those caught in the local fisheries (continental shelf) of Vietnam and Cambodia due to their high mean genetic diversity.

Background. Genetic traceability of seafood as well as population identification using molecular methods provide useful information about the fish origin and are important for protection of overfished populations, as well as for monitoring illegal, unreported, and unregulated (IUU) fisheries. The presently reported study focused on Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816)—a pelagic species with a wide range of distribution—especially important for many tropical countries, such as India, Philippines, and Thailand. This paper is the first part of a larger project: ”Development of a genetic-based system for identification of food products from fisheries and aquaculture introduced to the European Union customs area”. Materials and methods. Samples consisting of fin fragments of Indian mackerel were obtained from local markets in Thailand (MTH), Vietnam (SVN), Cambodia (SKH), and Madagascar (SMG) within 2012–2013. Two genes were analysed: nuclear rhodopsin gene (RH1) and mitochondrial D-loop (D-loop) region through RFLP analysis simulation and sequencing. Additionally, the samples from Cambodia and Madagascar were analysed with eight microsatellite loci (SSR). The data processing was aided by GenAlEx 6.5 and GeneClass2 software. Results. A comparison of the RH1 gene section revealed a total homology among the studied samples. A comparative analysis of D-loop sequences in the studied groups revealed intrapopulational diversity for MTH-, SKH-, SMG-, and SVN samples, at the level of 1, 1, 0.5, and 0.6 percentage points, respectively. Furthermore, the D-loop sequences identified a characteristic restriction site for SMG population. Based on the allele frequencies, we randomly assigned selected individuals to their original populations. GeneClass2 software correctly assigned only 16 out of 21 individuals to either the Cambodian or the Madagascar population, which jointly constituted 76% of all samples. We demonstrated, using AMOVA and GenAlEx 6.5, that the highest level of variability occurred among individuals within the respective populations, while the lowest interpopulation diversity was between the SMG and SKH populations. Conclusion. Our results may help the relevant authorities in the countries of the European Union to identify Indian mackerel and especially its products and trace them to the respective locality. Our findings may also be used for species-specific conservation measures hopefully undertaken by fisheries authorities of the countries where we took our samples. Results on other fish species, prepared in the frames of the same project, will be presented in other papers that will follow soon.

Characterization of asymptomatic KHV carriers may help understand virus transmission and storage. Such information allows farmers to minimize KHV on farms where this virus is present, also in common carp (Cyprinus carpio) monocultures. As asymptomatic KHV carriers, freshwater mollusks from the Unionidae family (swan mussels, Anodonta cygnea) and crustaceans from the Gammaridae family (scud, Gammarus pulex) were studied because of their unique method of feeding by accumulating bacterial and viral particles. The KHV genome was detected by nested PCR and confirmed by PCR recognizing the KHV glycoprotein gene in ORF 56 (KHV-U). Both PCR and nested PCR, which recognize the KHV thymidine kinase gene, always produced negative results in the swan mussels and scud samples.