rss_2.0Fisheries & Aquatic Life FeedSciendo RSS Feed for Fisheries & Aquatic Lifehttps://sciendo.com/journal/AOPFhttps://www.sciendo.comFisheries & Aquatic Life Feedhttps://sciendo-parsed.s3.eu-central-1.amazonaws.com/6470afd771e4585e08aa3072/cover-image.jpghttps://sciendo.com/journal/AOPF140216Genetic characteristics of Atlantic salmon () stocking material released into Polish rivershttps://sciendo.com/article/10.2478/aopf-2023-0017<abstract> <title style='display:none'>Abstract</title> <p>In Poland, stocking rivers with Atlantic salmon (<italic>Salmo salar</italic> L.) began in the nineteenth century, and become intensive in the 1990s. Currently, it is performed by the Polish Angling Association, and institutions involved in the program “Stocking Polish Marine Areas.” The aim of this study was to evaluate the genetic variation of the salmon stocked in recent years in Poland. For this purpose, salmon stocks from three broodstocks and two river populations (Słupia and Parsęta) were investigated. Eleven microsatellite loci were amplified. The total number of alleles detected across all loci ranged from 46 to 81 in the stocks. The average observed heterozygosity across all investigated loci was 0.59; and the expected heterozygosity was 0.58. The populations remained in Hardy–Weinberg equilibrium. The average Garza-Williamson <italic>M</italic> index value for all populations was low suggesting a reduction in genetic variation because of the founder effect. Genetic distance among populations was high between the Lithuanian stock (Rutki and Parsęta) and the group of Latvian origin (Aquamar–Żelkówko–Słupia). Several admixture traces were recorded in all stocks with the smallest evidence of this in the Rutki stock. Inbreeding values per generation were typical of those observed in breeding stocks (0–3%). The effective population size values were low or very low for all the stocks (<italic>Ne 15-37)</italic>.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00172024-02-08T00:00:00.000+00:00The induction of meiotic gynogenesis in Northern pike () using the heterologous European perch () spermhttps://sciendo.com/article/10.2478/aopf-2023-0018<abstract> <title style='display:none'>Abstract</title> <p>Northern pike (<italic>Esox lucius</italic> L.) is one of the fish species whose production in freshwater aquaculture may increase in the next few years. One method of producing this species is to create monosex stocks of pike, as females grow faster, mature later and gain larger body sizes. They can be obtained in the process of gynogenesis. The aim of this research was to determine and optimize the conditions of UV irradiating European perch (<italic>Perca fluviatilis</italic> L.) spermatozoa to inactivate them genetically (first experiment). The aim of this study was also to confirm whether perch spermatozoa can be used to induce northern pike gynogenesis using thermal shock (second experiment). During first experiment the highest rate of haploid larvae (29.9 ± 0.85%) was noted in the group inseminated with perch sperm irradiated for 6 min (1548 J m<sup>-2</sup>). No viable embryos were observed in groups of eggs inseminated with sperm irradiated for more than 10 minutes (2580 J m<sup>-2</sup>). The heat shock applied 12 or 14 min after gamete activation, for 3 or 5 min at 34.0°C, resulted in obtaining of gynogenetic specimen due to retention of the second polar body in all experimental groups. The most efficient was heat shock applied 14 min after gamete activation and lasting 3 min, and resulted in 18.5 ± 1.3% of gynogenetic larvae for female B. Heat shock applied 12 min after gamete activation, lasting 3 min was also effective in the case of female A, resulting in obtaining of 16.5 ± 2.1% gynogenetic specimen.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00182024-02-08T00:00:00.000+00:00Length-weight relationship and morphometric and meristic variation in Dinnawah snowtrout, , inhabiting the Suru River and its tributaries of Kargil, Ladakh Regionhttps://sciendo.com/article/10.2478/aopf-2023-0019<abstract> <title style='display:none'>Abstract</title> <p>Morphometric variations across fish stocks have long been acknowledged as useful for determining population structure and identifying stocks. <italic>Schizothorax progastus</italic> (McClelland) is a common, dominant fish in most cold-water rivers and is considered a good sport fish and also delicious in taste. For the people of Ladakh, this fish is a significant source of nutrition. A total of 70 specimens were collected for this study. A total of 24 morphometric and six meristic characters were studied, with 18 morphometric characters assessed as percentages of total length and four characters analyzed as percentages of head length. Standard length and fork length had the strongest correlations with total length at 0.98 and 0.99, respectively. Overall, the findings demonstrated that all morphometric features had linear correlations and exhibited a high degree of association (P &lt; 0.05). The meristic counts examined in this study were consistent among all fish of various sizes, suggesting that body size had no effect on them. The biological information generated from this study serves as an essential guideline for future management and conservation of <italic>S. progastus</italic>, an important food source in the Ladakh, Trans Himalayan region.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00192024-02-08T00:00:00.000+00:00Erythrocytic nuclear abnormalities in L. cultivated in water bodies of agroecosystemshttps://sciendo.com/article/10.2478/aopf-2023-0021<abstract> <title style='display:none'>Abstract</title> <p>Agrochemicals contaminate water bodies in agroecosystems, which affects the health of fishes. We assessed erythrocytic nuclear abnormalities (ENA) in <italic>Cyprinus carpio</italic> reared in uncontaminated and contaminated water bodies. We recorded micronucleus, notched nucleus, lobed nucleus, kidney bean-shaped nucleus, bi-nucleated, blebbed nucleus, karyopyknosis, nuclear shift, ooze out nucleus, and elongated nucleus at higher incidences in fish reared in the contaminated site. We observed a high percent incidence of ENA and micronucleus in fish from the contaminated site. The analysis of heavy metals with atomic absorption spectroscopy revealed that all heavy metals (Mn, Zn, Ni, Pb, Cd, Fe) were high in the contaminated site except for Cu in water and Cu and Cr in sediments. Correlation matrix analysis showed that total ENA increased with Cu (r = 0.996, p &lt; 0.0001), Mn (r = 0.942, p &lt; 0.0001), Zn (r = 0.517, p = 0.07), and Cr (r = 0.997, p = 0.0001). Compared to the uncontaminated site, the incidence of micronuclei was 20 times higher in the fish from the contaminated site, and this was influenced by the Cu, Mn, Zn, and Cr contents in the sediments. This study indicated that the heavy metal contamination of a water body located in an agroecosystem contributed to nuclear abnormalities in <italic>C. carpio</italic>.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00212024-02-08T00:00:00.000+00:00Effects of chlorpyrifos on histopathological biomarkers of the freshwater teleost https://sciendo.com/article/10.2478/aopf-2023-0020<abstract> <title style='display:none'>Abstract</title> <p>An attempt was made to evaluate histopathological changes in the gills, liver, and kidney tissues of the freshwater teleost <italic>Oreochromis niloticus</italic> as biomarkers of chlorpyrifos toxicity. An experiment was conducted in glass aquaria with <italic>O. niloticus</italic> exposed for 28 days to sub-lethal concentrations of chlorpyrifos of 0.0 µg L<sup>−1</sup> (control), 10 µg L<sup>−1</sup>, and 20 µg L<sup>−1</sup>. Chlorpyrifos caused distortions of the primary gill lamellae structure, the curling of secondary lamellae, desquamation, and epithelial hyperplasia on secondary gill filaments. Hepatocyte vacuolation and nuclear membrane necrosis were found in the liver. Additionally, the shrinkage of the glomeruli, thickening of Bowman’s capsule, glomerular and tubular necrosis, intracytoplasmic vacuoles, and hyaline degeneration in the renal tubule were seen in the kidney of <italic>O. niloticus</italic> exposed to chlorpyrifos. No remarkable lesions were observed in the control group. The severity of lesions in the fish tissues was assessed using the standard semi-quantitative grading system. The degree of histopathological lesions in various fish tissues was found to increase with chlorpyrifos concentrations. Histopathological lesions appeared to be good biomarkers of chlorpyrifos toxicity.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00202024-02-08T00:00:00.000+00:00Length-weight relationships and condition factors of three freshwater fish species – (Ham.), L., and (Sykes) – from the Sutlej River, Indiahttps://sciendo.com/article/10.2478/aopf-2023-0022<abstract> <title style='display:none'>Abstract</title> <p>Waterbodies are polluted by human activities or the increasing intensity of these activities, and this affects fish populations. The quality of the water fish inhabit directly impacts their growth and overall health. Length-weight relationships (LWRs) and relative condition factors (K<sub>n</sub>) were estimated for three freshwater fish species from the Sutlej River of India from October 2020 to May 2022. A total of 232 fish specimens were caught with cast and gill nets in Gobindsagar Reservoir, Himachal Pradesh and Ropar Wetland, Punjab. Total length was strongly correlated with all the morphological characters (p &lt; 0.001). The growth coefficients calculated (b) for <italic>Bangana dero</italic>, <italic>Cyprinus carpio</italic>, and <italic>Sperata seenghala</italic> were 2.858, 2.506, and 2.555, respectively, and indicated negative allometric growth. The correlation coefficients (r) indicated strong linear relationships between the weights and lengths of all three fish species. The outcomes of this study will help fisheries researchers, environmentalists, and scientists to develop future monitoring and conservation strategies for these fish species.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00222024-02-08T00:00:00.000+00:00Time-dependent changes in oxidative stress biomarkers and activities of lysosomal and antioxidant enzymes in hepatic tissue of rainbow trout ( Walbaum) following vaccination against https://sciendo.com/article/10.2478/aopf-2023-0014<abstract> <title style='display:none'>Abstract</title> <p>This study analyzed time-dependent effects of vaccination against <italic>Y. ruckeri</italic> on the oxidative mechanism underlying those effects by detecting relevant lipid peroxidation (2-thiobarbituric acid reactive substances, TBARS) and protein oxidation biomarkers [aldehydic and ketonic derivatives of oxidatively modified proteins (OMP)], antioxidant defenses [activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), total antioxidant capacity (TAC)], as well as activities of lysosomal functioning [alanyl aminopeptidase (AAP), leucyl aminopeptidase (LAP), acid phosphatase (AcP), and β-N-acetylglucosaminidase (NAG)] in hepatic tissue of rainbow trout, <italic>Oncorhynchus mykiss</italic> (Walbaum) following anti-<italic>Y. ruckeri</italic> vaccination in the first, second, and sixth months. A concentrated vaccine with <italic>Y. ruckeri</italic> strains was enclosed in fish feed and was administered three times every other day. Rainbow trout from each group were euthanized 31, 61, and 181 days following vaccination, and hepatic tissue was sampled for analysis. In the current study, vaccination against <italic>Y. ruckeri</italic> resulted in a no statistically significant change in TBARS levels, while aldehydic and ketonic derivatives of OMP in hepatic tissue decreased, especially after the first and second months following immunization. Moreover, the activities of glutathione-dependent enzymes increased, especially after the first and sixth months. The highest TAC levels were observed two and six months after vaccination. It has been shown that vaccination-related oxidative stress in hepatic tissue is involved in adaptive responses through the temporary mobilization of antioxidant and lysosomal enzymes in rainbow trout. The present study showed the effect of vaccination on lysosome membrane permeability for carbohydrate cleavage after the development of immunity against <italic>Yersinia</italic>, whereas antioxidant defence was reduced. Our results confirmed that the concept of preserving antioxidant enzyme function after vaccination was also evident when CAT, GR, and GPx activities either increased or were unchanged following vaccination.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00142024-02-08T00:00:00.000+00:00Do immunomodulatory substances facilitate recovery from stress caused by feed changes in juvenile brown trout ( m. L.)?https://sciendo.com/article/10.2478/aopf-2023-0013<abstract> <title style='display:none'>Abstract</title> <p>The aim of the study was to determine the influence of feeds with or without β-glucan-based immunomodulatory supplements (groups BF and UB or B and U, respectively; feeding period 14 and 28 days) on the welfare of brown trout. The diets tested did not influence the rearing indices. The type of feed and the feeding period were confirmed to have a significant influence on the white blood cell (WBC) count. WBC counts were lower than those in the initial sample particularly on day 14 of the experiment. Red blood cell (RBC) counts and hematocrit (HCT) were determined by feeding period, and the values of these parameters decreased the longer the tested feeds were applied. These changes were accompanied by increases in the values of mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC). Feed type determined levels of chloride ion (Cl<sup>-</sup>) and ammonia (NH<sub>3</sub>) and alkaline phosphatase (ALP) activity and feeding period affected sodium (Na<sup>+</sup>) and albumin (ALB) concentrations, while aspartate aminotransferase (AST) activity depended on both factors. Changes in leukograms were noted in all the groups, inter alia, significant increases in the share of lymphocytes, and after changing diets, decreases in the percentage of neutrophils, myeloperoxidase activity (A<sub>MPO</sub>) in phagocytes and cidal ability (CA). After day 28, A<sub>MPO</sub> and CA values increased and were significantly higher in groups BF and UB.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00132024-02-08T00:00:00.000+00:00Histology and histochemistry of the stomach of an Asian schilbeid, (Hamilton)https://sciendo.com/article/10.2478/aopf-2023-0015<abstract> <title style='display:none'>Abstract</title> <p>The cellular peculiarities and histochemical nature of the stomach in the freshwater catfish <italic>Clupisoma garua</italic> (Hamilton) were explored with light microscopic analysis. The pouch shaped muscular stomach was distinguished into the anterior cardiac and posterior pyloric regions. Histologically, the wall of stomach consisted of four distinct layers of the mucosa, submucosa, muscularis, and very thin serosa. The mucosa contained two kinds of epithelia: the superficial epithelium lined with columnar epithelial cells and the glandular epithelium crowded with numerous gastric glands that open through gastric pits. The vascularized submucosa was made up of loose connective tissues that extended into the mucosa forming lamina propria. The well-developed muscular layer was composed of an inner thick layer of circular muscle and an outer layer of longitudinal muscle bands. The detection and localization of mucopolysaccharides, glycogen, protein, and tryptophan in the various cells bounded in the stomach were described with the feeding behavior of the fish concerned.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00152024-02-08T00:00:00.000+00:00Improved innate immunity in juvenile vimba bream () fed a dry diet with an additive of hydrochloric acid (HCl)https://sciendo.com/article/10.2478/aopf-2023-0012<abstract> <title style='display:none'>Abstract</title> <p>A few reports indicate the beneficial effects of organic acids and their salts on anti-infective immunity in fish species. In the role of immunostimulants, inorganic acids may prove to be a much cheaper alternative to their organic equivalents. However, no report has described the effect of using inorganic acid as a feed additive on fish immunity. This study is the first attempt to evaluate the effect of hydrochloric acid (HCl) as a fish feed supplement on cellular immunity in the stomachless fish, cypriniform vimba bream, <italic>Vimba vimba</italic> (L.). Two groups, three replicates each, of juvenile vimba were fed a commercial dry fish diet or its variant containing a 1.5% additive of HCl for 55 days. The experiment was conducted in a recirculating aquaculture system at 25°C. Mortality, growth, condition factor, feed conversion ratio, respiratory burst activity (RBA), potential killing activity (PKA), and the proliferative response of head kidney lymphocytes were determined for both groups at the end of the experiment and compared. The PKA was higher in the group fed the diet with HCl. For all other parameters studied, there were no significant differences between the experimental groups. The results of the current study prove that the dietary additive of inorganic hydrochloric acid can substantially improve immune response to bacterial infections in juvenile vimba bream.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00122024-02-08T00:00:00.000+00:00Changes in the fish community of the Czarna Hańcza River (NE Poland) after a fish kill caused by a wastewater treatment plant failurehttps://sciendo.com/article/10.2478/aopf-2023-0016<abstract> <title style='display:none'>Abstract</title> <p>Mass fish kills caused by wastewater treatment plant (WWTP) failure are uncommon. In this study, we analyzed the recovery of the fish community in the Czarna Hańcza River after a fish kill caused by a WWTP incident in Suwałki in 2018. The research focused on brown trout, the dominant fish species in this river. The incident lasted about six hours and accounted for 7% of the mean river’s flow during the accident. The fish population recovered quickly, and ten months after the fish kill, the number of fish species and their abundance were similar to the pre-incident state, but the species structure was different. In subsequent years, fish species richness decreased conspicuously, while their numbers remained at a high, relatively constant level. Species that are more resistant to difficult environmental conditions, such as white bream and European perch, returned to the river first. Concurrently with the improvement of environmental conditions, more demanding species, including brown trout, began to dominate in the river. Fulton’s condition factors decreased significantly as the river self-purified and the density of the brown trout population increased (P &lt; 0.05). Our results indicated that the brown trout population was able to recover relatively quick, presumably because of stocking. Other species that were not stocked required more time to recover.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00162024-02-08T00:00:00.000+00:00Length-weight relationships and Fulton’s condition factors of two flatfishes, and , from Cox’s Bazar coast, Bay of Bengalhttps://sciendo.com/article/10.2478/aopf-2023-0008<abstract><title style='display:none'>Abstract</title> <p>Length-weight relationships (LWRs) and Fulton’s condition factor were estimated for two flatfishes, <italic>Cynoglossus lingua </italic>Hamilton, and <italic>Cynoglossus cynoglossus </italic>(Hamilton), from the Cox’s Bazar coast of Bangladesh. Sampling was done from September to November 2022 from the landing center of Bangladesh Fisheries Development Corporation. In this study, the maximum total length of <italic>C. cynoglossus </italic>(34.0 cm) is a new record for this species. The length-weight relationships for these two species were highly significant (P &lt; 0.001) with adjusted r<sup>2 </sup>values of 0.918 and 0.927 for <italic>C. lingua </italic>and <italic>C. cynoglossus</italic>, respectively. The calculated growth coefficient (b) for <italic>C. lingua </italic>and <italic>C. cynoglossus </italic>was 2.873 and 3.359, respectively. The estimated Fulton’s condition factor (Kn) was 0.42 ± 0.05 for <italic>C. lingua </italic>and 0.72 ± 0.11 for <italic>C. cynoglossus</italic>. No information about the population parameters of <italic>C. lingua </italic>from the Bay of Bengal has been reported previously in any scientific database. The maximum Kn value of <italic>C. lingua </italic>was observed in the 13.0–15.9 cm length class while that of <italic>C. cynoglossus </italic>was found in the 31.0–33.9 cm length class. Our estimated LWR and Fulton’s condition factor values for these two flatfishes can be useful for management and conservation.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00082023-09-06T00:00:00.000+00:00UDN-like disease in spawners of salmonid fishes from the Rega, Parsęta, Wieprza, and Słupia rivers in 2009-2012https://sciendo.com/article/10.2478/aopf-2023-0007<abstract><title style='display:none'>Abstract</title> <p>Since 2007 in Poland, skin lesions have been observed in salmon (<italic>Salmo salar </italic>L.) and sea trout (<italic>Salmo trutta </italic>L.) entering Pomeranian rivers to spawn. The clinical picture of affected fish resembled ulcerative dermal necrosis (UDN), a disease of unknown etiology affecting mainly the scalps of wild salmonids. The aim of the 2009-2012 study was to determine with microbiological tests the etiological agent of the skin lesions observed in salmonids entering the Pomeranian rivers. During the study, a total of 13 species of Gram-negative bacteria belonging mainly to the Yersiniaceae, Enterobacteriaceae, and Pseudomonadaceae families were isolated and identified from the skin and kidneys of diseased fish. The Gram-positive bacteria isolated were aerobic, hemolytic granules of the genus Streptococcus. Mycological examinations on damaged fish body surfaces revealed yeasts of the genus <italic>Rhodotorula </italic>and fungi of the family Saprolegniaceae. The results of our study did not permit us to identify unequivocally the direct cause of the fish diseases analyzed since all the bacteria isolated during the study are normally found in aquatic environments. Some of the isolated bacteria identified were assumed to be potentially pathogenic to fish. The fungal infections observed were probably secondary and only exacerbated ongoing disease processes.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00072023-09-06T00:00:00.000+00:00Evaluation of the antibacterial activity of cultivated Caucasian whortleberry (L.) against fish pathogenshttps://sciendo.com/article/10.2478/aopf-2023-0009<abstract><title style='display:none'>Abstract</title> <p>Bacterial diseases are one of the major factors hampering aquaculture sustainability. Antibiotics are used widely to treat or prevent infectious bacterial diseases in aquaculture. However, because of growing problems of antibiotic resistance caused by the imprudent use of antibiotics, sourcing environmentally benign alternatives, such as herbal/medicinal plants, is now the focus of many researchers. Hence, in this study, a minimum inhibitory concentration (MIC) test with broth microdilution was performed to determine the in vitro antibacterial activity of an aqueous methanolic extract of cultivated Caucasian whortleberry (<italic>Vaccinium arctostaphylos </italic>L.) against various fish pathogens, i.e., <italic>Yersinia ruckeri</italic>, <italic>Pseudomonas putida</italic>, <italic>P. luteola</italic>, <italic>Aeromonas salmonicida</italic>, <italic>A. hydrophila</italic>, and <italic>A. sobria</italic>. The results revealed that the MIC values of the aqueous methanolic extract against <italic>Y. ruckeri</italic>, <italic>P. putida</italic>, <italic>P. luteola</italic>, <italic>A. salmonicida</italic>, and <italic>A. hydrophila </italic>were 8.75 mg mL<sup>−1</sup>, while against <italic>A. sobria </italic>it was 2.19 mg mL<sup>−1</sup>. This study indicated that the medicinal plant <italic>V. arctostaphylos </italic>L. can potentially be used against all the fish pathogens tested thanks to its various important bioactive compounds. However, to assess the potential of this plant, further in vivo studies should be carried out.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00092023-09-06T00:00:00.000+00:00Integrated cage-pond carp farming for increased aquaculture productionhttps://sciendo.com/article/10.2478/aopf-2023-0010<abstract><title style='display:none'>Abstract</title> <p>The study investigated the potential for increasing carp (<italic>Cyprinus carpio </italic>L.) production in temperate climates without expanding farming area and simultaneously reducing wastewater discharge in intensive fish production using an in-pond cage system. An earthen pond with a stocking density of 209.3 kg per ha<sup>−1 </sup>and four cages stocked with 8.12 kg m<sup>−2 </sup>(A1 and A2) and 2.61 kg m<sup>−2 </sup>(B1 and B2) were monitored. The gross yield from the cages was 27.09 kg m<sup>−2 </sup>(A1), 24.3 kg m<sup>−2 </sup>(A2), 10.09 kg m<sup>−2 </sup>(B1), and 9.73 kg m<sup>−2 </sup>(B2). The fish in the pond had the highest specific growth rate (SGR) at 0.98%, and the feed conversion ratio (FCR) was above 3 for all the cages. The cages provided a high enough nutrient load to enable a net fish production of about 450 kg ha<sup>−1</sup> in the pond. Ineffective feed utilization affected the production performance in the cages. Thanks to the high yield obtained in the pond, the overall return on the investment was 16%, which rendered production profitable.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00102023-09-06T00:00:00.000+00:00The history of the Atlantic sturgeon, Mitchill, 1815, in the Warta River of Central and Western Poland in the nineteenth century based on Polish sourceshttps://sciendo.com/article/10.2478/aopf-2023-0011<abstract><title style='display:none'>Abstract</title> <p>An analysis of Polish historical sources indicates that there are no references to sturgeon in the Warta River basin before 1810. It is hypothesized that there was no autochthonic sturgeon population in this river in historic times. The occasional occurrence of fish in the Warta River stemmed from their straying from the Oder River, especially during high waters. The situation changed in the second half of the nineteenth century because increasing pollution in the Oder River meant increasing numbers of fish entered the Warta River. Peak catches by fishers in Poznań were in the 1880s and early 1890s, after which the population collapsed and never recovered. Overfishing in this period stemmed primarily from the effects of regulating the Warta River for navigation. The data presented herein might have implications for the current sturgeon reintroduction program being conducted in the Warta River basin.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00112023-09-06T00:00:00.000+00:00Contents of Cu, Cd, and As in , , and sp. from an anthropogenically loaded segment of the Danube River in Bulgariahttps://sciendo.com/article/10.2478/aopf-2023-0006<abstract> <title style='display:none'>Abstract</title> <p>The circulation of the contents of Cu, Cd, and As was traced in the system of <italic>Chondrostoma nasus</italic> – <italic>Pomphorhynchus laevis</italic> – <italic>Contracaecum</italic> sp. – water – sediments from the Danube River in the Kudelin biotope. New data on the content of the elements examined are presented. The concentrations of the three elements in the materials studied, which included tissues, organs, and parasites of common nase, and water and sediments from the Kudelin biotope, were higher than the limits set forth in Bulgarian and international legislative documents. The bioindicator role of the tissues, organs, and parasites examined was revealed, and the liver of common nase and <italic>Contracaecum</italic> sp. were good bioindicators for Cd content, while <italic>P. laevis</italic> was a good bioindicator for As content.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00062023-06-09T00:00:00.000+00:00Influence of temperature and stocking density during rearing on larval blue bream, (L.)https://sciendo.com/article/10.2478/aopf-2023-0004<abstract> <title style='display:none'>Abstract</title> <p>This study determined the effects of stocking density and water temperature on the rearing parameters and survival of larval blue bream under controlled conditions. Two experimental larval blue bream rearing variants were conducted. In the first experiment, larval blue bream were reared at different stocking densities of 20, 40, 80, and 120 indiv. dm<sup>−3</sup> at 25°C. In the second experiment, larvae were reared in water at 15, 20, 25, and 30°C at a stocking density of 40 individuals per dm<sup>3</sup>. The larval blue bream achieved the highest growth rate at the lowest density tested (20 indiv. dm<sup>−3</sup>; 69.4 mg at an average length of 26.8 mm) and at the highest temperature tested (30°C; 80.1 mg at an average length of 28.4 mm). The final larval survival rate during rearing at different temperatures ranged from 95.2 to 97.6%, while the final larval survival rate at different stocking densities ranged from 91.4 to 94.6%. The lowest growth and survival rates were recorded for larvae reared in water at 15°C and at a density of 120 indiv. dm<sup>−3</sup>.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00042023-06-09T00:00:00.000+00:00Different susceptibility to body deformities in juveniles of 13 European species (Cypriniformes: Pisces) intensively fed dry formulated diet under controlled conditionshttps://sciendo.com/article/10.2478/aopf-2023-0002<abstract> <title style='display:none'>Abstract</title> <p>The aim of this study was to compare the susceptibility to body deformities in juveniles of 13 common European cypriniform fish, caused by intensive feeding with the same commercial dry diet administered at 25°C according to a similar feeding schedule. The final share of individuals with body malformations differed considerably among species and was 0.0-87.0%. Unaffected by the intensive feeding were only <italic>Barbus barbus</italic> (L.), <italic>Chondrostoma nasus</italic> (L.), <italic>Cyprinus carpio</italic> L. and <italic>Leuciscus aspius</italic> (L.). They can be safely fed with the highest rations of dry diet constituting 2,5-3% of fish biomass daily. Most of the species exhibited body malformations in a short time of only 20-30 days of feeding. <italic>Abramis brama</italic> (L.)<italic>, Leuciscus idus</italic> (L.)<italic>, Leuciscus leuciscus</italic> (L.)<italic>, Scardinius erythrophthalmus</italic> (L.)<italic>, Carassius carassius</italic> (L.)<italic>, Rutilus rutilus</italic> (L.) and <italic>Squalius cephalus</italic> (L.) proved to be highly prone to body deformities – daily ration of feed 2.5% of fish biomass resulted in high incidence of malformed individuals after 60 days of feeding (50-87%). For these species safe daily ration of a dry diet should not exceed 2% of total fish biomass. <italic>Tinca tinca</italic> (L.) and <italic>Vimba vimba</italic> (L.) showed medium susceptibility to body deformities (11 and 24%, respectively). They can be fed with the daily ration of a dry diet about 2,3% of fish biomass. Some regularities connected with different susceptibility to fish body deformities are discussed in the paper.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00022023-06-09T00:00:00.000+00:00Does the site of blood collection and sex of crucian carp () affect hematological and blood biochemical results?https://sciendo.com/article/10.2478/aopf-2023-0003<abstract> <title style='display:none'>Abstract</title> <p>Blood analysis is used to evaluate the effects of various environmental factors on fishes and to assess fish health and welfare. Fish blood is routinely sampled from the caudal vein or the heart. The aim of the present study was to determine the differences between venous and cardiac crucian carp (<italic>Carassius carassius</italic> (L.)) blood parameters. Additionally, the influence of sex was tested. The fish were divided into two groups: group I consisted of 10 males and 9 females, group II consisted of 8 males and 8 females. The fish from group I had blood sampled first from the caudal vein and then from the heart. The fish from group II had the procedures in the opposite order. The hematological parameters determined in the present study depended on the blood collection site and the sex of the individuals. Blood biochemical indices depended on the sex of the fish but not on the blood sampling site. The effect of sampling order was observed in the case of both hematological and biochemical parameters. The results of the current study indicated that the blood collection site, the sex of fish, and sampling order should be taken into consideration in hematological experiments.</p> </abstract>ARTICLEtruehttps://sciendo.com/article/10.2478/aopf-2023-00032023-06-09T00:00:00.000+00:00en-us-1