Genetic variability in European populations of Coregonus lavaretus (L.): an assessment based on mitochondrial ND-1 gene haplotypes

Abstract. The genetic variability of whitefish, Coregonus lavaretus (L.), was studied based on 114 individuals from nine populations inhabiting Polish lakes, including the Szczecin Lagoon, and from one population each from lakes in Austria and Switzerland. Differences within and among populations were assessed with mitochondrial ND-1 gene sequences that were PCR amplified and digested with ten restriction enzymes. The ten composite haplotypes obtained were sequenced and analyzed with MEGA4 software. The highest intrapopulation variability was noted in the whitefish populations inhabiting lakes Iñsko, Miedwie, Marianowo, Wisola, OEremskie, Morzycko, the Szczecin Lagoon, and Lake Lucerne, which possessed from two to five composite haplotypes. In contrast, populations inhabiting lakes Wooewin, Czarne, and Traunsee were fixed for the most common haplotype H2

Occurrence of exotic Russian sturgeons, Acipenser gueldenstaedtii Brandt et Ratzeburg, 1833 (Actinopterygii: Acipenseridae) in the Baltic Sea

Exotic species of acipenserid fishes have been frequently encountered in the commercial catches of the Baltic Sea, since the early 1990s. Such sightings are rarely reflected as published records. The present paper provides detailed descriptions of two specimens of Russian sturgeons, Acipenser gueldenstaedtii caught in the Exclusive Polish Economic Zone of the Baltic Sea

First record of the leopard pleco, Pterygoplichthys gibbiceps (Actinopterygii, Loricariidae) in the Brda River in the centre of Bydgoszcz (northern Poland)

Background. The presently reported finding of leopard pleco, Pterygoplichthys gibbiceps (Kner, 1854) (Loricariidae), in open waters of the Brda River in the centre of Bydgoszcz, constitutes the first record of a south-American loricariid fish species in Poland. The specimen found is described and illustrated. The finding is discussed in association with other alien species sightings in Poland. The described leopard pleco is possibly the next example of an emerging alien fish species in inland Polish waters

Chelon labrosus (Risso, 1827) - the first record from Lake Dąbie (Poland)

We report on the first occurrence of Chelon labrosus in a Polish estuary. One Ch. labrosus was caught with a fyke net in the northern part of Lake Dąbie (Odra estuary) on 14 November 2007. It measured 266.92 mm in overall length and weighed 176.8 g. The fish’s metric and meristic characters, age by scale, condition, sex and maturity stage (Maier’s scale) were determined

New and ‘visiting’ fish species collected off the Western coast of Poland (Baltic Sea) in 2007–2008 with a description of their parasite fauna

The first occurrence of striped red mullet Mullus surmuletus in the Pomeranian Bay (in 2007) and the occurrence of three very rarely noted species (tub gurnard Chelidonichthys lucerna, Atlantic horse mackerel Trachurus trachurus, thicklip grey mullet Chelon labrosus) collected in 2007–2008 in the Pomeranian Bay, Szczecin Lagoon and Lake Dąbie are reported. Their expansion is probably due to increased sea temperatures resulting from climate change, as well as the inflow of saline water. The ‘visitors’ hosted eight pathogens from four taxonomic groups: Protozoa, Nematoda, Acanthocephala and Mollusca. Nematodes, the most numerous ones, were found in three host species. All the parasite species were new for the hosts examined; only the larvae of the acanthocephalan Corynosoma strumosum had already been recorded in one of the hosts (Chelidonichthys lucerna). The stomachs of almost all the fish examined were empty, but the species composition of the parasite fauna found showed that the fish must have ingested some food in the Pomeranian Bay

Microsatellite DNA-based genetic traceability of two populations of splendid alfonsino, Beryx splendens (Actinopterygii: Beryciformes: Berycidae)—Project CELFISH—Part 2

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

Genetic identifiability of selected populations of Indian mackerel, Rastrelliger kanagurta (Actinopterygii: Perciformes: Scombridae)—CELFISH Project—Part 1

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.

Asian pangasiids—an emerging problem for European inland waters? Systematic and parasitological aspects

Background. Asian pangasiids (Actinopterygii: Siluriformes: Pangasiidae), commonly referred to as “panga”, have recently became an important item on the European fish markets. The fish are currently imported from south-east Asia but the growing consumers’ demand is likely to motivate European fish growers to culture the “panga” locally. This in turn could bring about unforeseeable consequences for the aquatic environment. The presently reported study provides the first record of a pangasiid fish (two specimens) from the European natural waters. We attempted to identify the fish through complex morphometric procedures and to study all their parasites, thus determining their potential threat for the environment. Materials and methods. Two specimens of pangasiid fish were captured in a pond, in the city of Szczecin, Poland. The fish were examined following procedures commonly accepted in morphological studies yielding detailed measurements. The key structures were described and illustrated (e.g., the shape of dentition on both the vomerine and palatine plates). The measurements were taken with an electronic calliper and a dissecting microscope (Nikon SMZ 1000), coupled with the Lucia Measurement System. Additionally, during necropsy, selected organs were checked for the presence of parasites. Results. One of the fish specimens hosted the monogenoid parasite, Thaparocleidus caecus, that has never been found in Europe. Metric and meristic characters of fish studied, as well as the presence of monogenoid T. caecus suggest that the fish found were representatives of Pangasianodon hypophthalmus, however, some features, especially those related to the ratio between fins and body or total length, differ markedly from the species description. Comparative analysis suggested that the two specimens collected in Szczecin are hybrids, most likely of P. hypophthalmus with other species, of unknown origin, presumably imported from Thailand. Conclusion. The specific identity of pangasiids imported alive to Europe should be monitored in the future. Additional genetic studies are needed. The monogenoid parasite found on the fish studied poses no threat to the native ichthyofauna (because of its very narrow host-specificity)

Parasitic copepods (Crustacea: Copepoda) infecting muscles of a marine fish (Actinopterygii: Moridae)—A spectacular effect on a host fish and a case of seafood identity fraud

Background. Automated processing of the fish caught on board a ship can potentially lead to a quality control breach. Specimens visibly infected with parasites are processed, frozen, and directed to the market. On the other hand, the removal of the body elements of taxonomic importance (e.g., fins, head, skin) opens gates to variously motivated seafood frauds. We had been alerted by local veterinary authorities about a fish consignment from the Falklands with a substantial volume of muscles with black contents. Materials and methods. The material for the presently reported study were decapitated, finless, and gutted fish delivered to our lab by the County Veterinarian of Szczecin (Purchased by a local importer from a Spanish fish wholesaler). The fish were labeled as “Pseudophycis bachus (Forster, 1801)”, and allegedly came from the Falklands. After thawing, the fish muscles were dissected, focusing on the distinctly black areas, examined following methods commonly used in parasitology, and observed under a dissecting and a compound microscope. Samples were collected also for molecular studies aiming to disclose the fish taxonomic identity. DNA barcoding gene (cytochrome c oxidase subunit I, COX1) was used to perform the genetic characterization for the collected fish specimens. The degree of similarity between the new records (MT318699 and MT318700) and the other records of Moridae species in the GenBank was assessed by building COX1 gene phylogeny. Results. The muscles contained large galls filled with black fluid. The fluid stained the adjacent muscles. Inside each gall, we found a single female of Sarcotaces sp., several “dwarf” males, eggs, and newly hatched nauplius stages. Using the molecular methods, the fish were identified as Mora moro (Risso, 1810). Conclusion. A preliminary veterinary inspection of the catch on board of fishing vessels may help to avoid huge financial losses when a parasitized fish consignment is rejected by veterinary authorities on land. It is evident that the European regulation regarding fish parasites requires an urgent revision. Mora moro does not occur off the Falklands as declared by the wholesaler. This seafood fraud was probably motivated by the urge to conceal a catch from European waters and thus avoid exceeding national fishing quotas. Species of the genus Sarcotaces require a revision backed by molecular methods

Population structure, condition, weight and length increments of anadromous form of European smelt (Osmerus eperlanus L.) from the Pomeranian Bay

The seasonality and catching of smelt in the Pomeranian Bay were analyzed. The growth rate of this species was analyzed based on the readings of the otoliths from 230 fishes caught during the monitoring catches. The average total length and standard length as well as the weight of smelt were respectively 141.76 mm (±25.18), 120.54 mm (±21.73) and 16.41g (±11.25). Between males and females the small, statistically insignificant differences were noted. Due to the linear correlation between R and TL, the back readings were made in the variant of Rosa–Lee. The obtained empirical datas were used to theoretically increase the length by model: von Bertalanffy, Ford–Walford, polynomial of the 2nd degree and modified power function. Among the mathematical models used in the paper, the growth of the fish most suited to back readings turned out to be a modified power function. The relation between the total lengths and the weights of the smelts from the waters of the Pomeranian Bay is described by the equation for the whole material: y = 0.0015x3.4633.Przeanalizowano sezonowość i współczesne połowy stynki w Zatoce Pomorskiej. Na tym tle, na podstawie odczytów na otolitach 230 stynek złowionych w czasie połowów monitoringowych, przeanalizowano tempo wzrostu tego gatunku. Średnia długość całkowita i długość ciała oraz masa jednostkowa złowionych stynek wyniosła odpowiednio 141,76 mm (±25,18), 120,54 mm (±21,73) oraz 16,41 g (±11,25). Zanotowano niewielkie, nieistotne statystycznie różnice między samcami a samicami. Z uwagi na prostoliniową zależność między promieniem łuski (R) i całkowitą długością ciała (TL) odczyty wsteczne wykonano w wariancie Rosy–Lee. Uzyskane dane empiryczne wykorzystano do obliczenia teoretycznego wzrostu długości stynki z użyciem matematycznych modeli wzrostu: von Bertalanffy’ego, Forda–Walforda, wielomianu 2. stopnia i zmodyfikowanej funkcji potęgowej. Spośród zastosowanych modeli wzrostu ryb najbardziej dopasowanym do odczytów wstecznych okazała się zmodyfikowana funkcja potęgowa. Zależność między długością całkowitą a masą jednostkową stynki z wód Zatoki Pomorskiej opisuje równanie dla całego materiału: y = 0,0015x3,4633