Fisheries & Aquatic Life

Genetic characteristics of Atlantic salmon (Salmo salar) stocking material released into Polish rivers

2024-02-05T08:31:56+01:00

In Poland, stocking rivers with Atlantic salmon (Salmo salar 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 M 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 (Ne 15-37).

The induction of meiotic gynogenesis in Northern pike (Esox lucius) using the heterologous European perch (Perca fluviatilis) sperm

2024-02-05T08:32:02+01:00

Northern pike (Esox lucius 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 (Perca fluviatilis 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^-2). No viable embryos were observed in groups of eggs inseminated with sperm irradiated for more than 10 minutes (2580 J m^-2). 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.

Length-weight relationship and morphometric and meristic variation in Dinnawah snowtrout, Schizothorax progastus, inhabiting the Suru River and its tributaries of Kargil, Ladakh Region

2024-02-05T08:32:08+01:00

Morphometric variations across fish stocks have long been acknowledged as useful for determining population structure and identifying stocks. Schizothorax progastus (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 < 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 S. progastus, an important food source in the Ladakh, Trans Himalayan region.

Effects of chlorpyrifos on histopathological biomarkers of the freshwater teleost Oreochromis niloticus

2024-02-05T08:32:13+01:00

An attempt was made to evaluate histopathological changes in the gills, liver, and kidney tissues of the freshwater teleost Oreochromis niloticus as biomarkers of chlorpyrifos toxicity. An experiment was conducted in glass aquaria with O. niloticus exposed for 28 days to sub-lethal concentrations of chlorpyrifos of 0.0 μg L^-1 (control), 10 μg L^-1, and 20 μg L^-1. 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 O. niloticus 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.

Erythrocytic nuclear abnormalities in Cyprinus carpio L. cultivated in water bodies of agroecosystems

2024-02-05T08:32:17+01:00

Agrochemicals contaminate water bodies in agroecosystems, which affects the health of fishes. We assessed erythrocytic nuclear abnormalities (ENA) in Cyprinus carpio 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 < 0.0001), Mn (r = 0.942, p < 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 C. carpio.

Length-weight relationships and condition factors of three freshwater fish species – Bangana dero (Ham.), Cyprinus carpio L., and Sperata seenghala (Sykes) – from the Sutlej River, India

2024-02-05T08:32:21+01:00

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_n) 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 < 0.001). The growth coefficients calculated (b) for Bangana dero, Cyprinus carpio, and Sperata seenghala 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.

Obituary for Bronisław Długoszewski

2024-02-05T08:41:30+01:00

It was with great regret that we received the news of the unexpected death of our colleague, Bronek Długoszewski. He passed away at the age of 74, on Christmas Eve 2023, plunging his family and friends into grief. The Inland Fisheries Institute has lost a respected specialist in the field of hydroacoustics, and Polish spearfishing has lost another legend. For 44 years, Bronek was an employee of the Department of Fisheries Technology, and later of the Laboratory of Hydroacoustics – at the Inland Fisheries Institute in Olsztyn. He had a great knowledge of fish, which was the main object of his interest, both professional and hobby. He also had many years of experience in working on and under water. He was a valued employee, co-author of over 20 scientific publications in Polish and foreign journals, participant of a number of scientific projects, including foreign ones (France, Norway, Hungary, China), as well as a winner of many trophies of the Spearfishing Poland Association. He was an extraordinary person, a man whose whole life was an underwater kingdom. The doyen of spearfishing, an exceptional, good and wise man. His modesty, nobility and kindness will forever remain in our memory. Rest in peace, dear Friend.