Event Abstract Back to Event Preliminary results of the salmonids monitoring in the river Rega (north-western Poland) Krzysztof Formicki1*, Beata Więcaszek1, Przemysław Czerniejewski1, Agnieszka Rybczyk1, Adam Tański1, Agata Korzelecka-Orkisz1, Teresa Ostaszewska2 and Zdzisław Zakęś3 1 West Pomeranian University of Technology, Poland 2 Warsaw University of Life Sciences, Poland 3 Stanisław Sakowicz Inland Fisheries Institute, Poland River Rega is 167.8 km long, of high average gradient (21.80 m3/s) which disembogues to the Baltic Sea. Rega, with well-oxygenated waters is extremely important ecological passageway for migrating for spawning salmonids (Salmo salar and Salmo trutta) as well as it is a perfect habitat for non-migratory salmonids species such a Salmo trutta fario or Thymallus thymallus. The main sites of salmon and sea trout spawning are below the hydropower Rejowice, below the Gryfice dam, in the region of Trzebiatów village, Brodziec and Lubieszowa streams. In 2018-2019 the stocktake of salmonids fish in the basin of Rega river was performed. All salmonids fish were measured (TL, total length) and weighed, the age was estimated by the scale reading; in addition the condition of fish was calculated (the Fulton and Clark coefficients) and the diet composition was examined. The electrofishing was performed in July 2018 in the rivers: Ukleja, Brzeźnicka Węgorza, Piaskowa, Sąpolna; in October 2018 in Rega, Mołstówka, and in January 2019 in Rega again. 25.86% of fish collected were salmonids (Salmo trutta, Salmo trutta fario, Thymallus thymallus). The sea trout contributed to 40.0% of the whole salmonid sample, the brown trout to 43.33% and European grayling to 16.67%. Salmo trutta were collected during the back migration after spawning in the river Rega. The range of total length was 51.0-61.0 cm (mean 55.8cm) and weight was ranged from 880.9 – 2169.9g (mean 1541.7g). The average value of the Fulton and Clark coefficient were 0.89±0.17 and 0.87±0.17, respectively. The stomachs and alimentary tracts were empty. The age ranged within 5-6 years, with average value of 5.25 (river age 2-3, sea age 2-3). Graylings were collected in July in the river Brzeźnicka Węgorza (tributary of Rega river) and in October 2018 in Rega. The range of total length was 20.5-31.1 cm (mean 25.24 cm) and weight was ranged from 74.6-295.6g (mean 166.04g). The average value of the Fulton and Clark coefficient were 0.94±0.10 and 0.83±0.10, respectively. In the alimentary tracts of T. thymallus the following diet components were found: representatives of Diptera (larvae of Chironomidae and Ephemeroptera, adults of Trichoptera, Ephemeroptera, Plecoptera, Coleoptera, Lepidoptera, and Crustacea (Copepoda Gammarus spp.). In addition, the presence of Annelida (Oligochaeta), Acari (Hydracarina), and Donata was recorded. The age ranged within 2-3 years (2 years old fish were immature). The brown trout S. trutta fario occupied 4 of 6 examined rivers. The range of total length was 12.2 – 23.0 cm (mean 17.77 cm) and weight was ranged from 17.2 -137.4g (mean 73.49g). The average value of the Fulton and Clark coefficient were 1.16±0.10 and 1.01±0.11, respectively. The high values of condition coefficients resulted from the pre-spawning period of sampling. In the alimentary tracts of S. trutta fario the following diet components were found: Trichoptera, Ephemeroptera, Diptera and Homoptera, as well as undetermined remains of Amphipoda and Molusca. The age ranged within 2-3 years (2 years old fish were immature and they were prevailing). Preliminary data obtained in this study show that river Rega is an important habitat both for migratory and non-migratory salmonids in the northern Poland. Besides the protection of these unique sites in this area, it is necessary to employ the active procedures of conservation, namely the more intensive stocking with the Salmo salar smolts as well as to arrange the natural spawning grounds to provide an opportunity to salmonids to spawn in the areas where the proper substrate is lacking. Acknowledgements The study was done within the project no 00001-6521.1-OR1600002/17/18 financed by the Sectoral Operational Programme "Fisheries and See 2014-2020" Keywords: salmonids,, Rega river, Support in spawning, arrangemend of the natural spawning grounds, Baltic Sea Conference: XVI European Congress of Ichthyology, Lausanne, Switzerland, 2 Sep - 6 Sep, 2019. Presentation Type: Poster Topic: ECOLOGY AND LIFE CYCLES Citation: Formicki K, Więcaszek B, Czerniejewski P, Rybczyk A, Tański A, Korzelecka-Orkisz A, Ostaszewska T and Zakęś Z (2019). Preliminary results of the salmonids monitoring in the river Rega (north-western Poland). Front. Mar. Sci. Conference Abstract: XVI European Congress of Ichthyology. doi: 10.3389/conf.fmars.2019.07.00157 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 May 2019; Published Online: 14 Aug 2019. * Correspondence: Prof. Krzysztof Formicki, West Pomeranian University of Technology, Szczecin, Poland, Krzysztof.Formicki@zut.edu.pl Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Krzysztof Formicki Beata Więcaszek Przemysław Czerniejewski Agnieszka Rybczyk Adam Tański Agata Korzelecka-Orkisz Teresa Ostaszewska Zdzisław Zakęś Google Krzysztof Formicki Beata Więcaszek Przemysław Czerniejewski Agnieszka Rybczyk Adam Tański Agata Korzelecka-Orkisz Teresa Ostaszewska Zdzisław Zakęś Google Scholar Krzysztof Formicki Beata Więcaszek Przemysław Czerniejewski Agnieszka Rybczyk Adam Tański Agata Korzelecka-Orkisz Teresa Ostaszewska Zdzisław Zakęś PubMed Krzysztof Formicki Beata Więcaszek Przemysław Czerniejewski Agnieszka Rybczyk Adam Tański Agata Korzelecka-Orkisz Teresa Ostaszewska Zdzisław Zakęś Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.
AbstarctMagnetic field affects many living organisms, fishes included. The fish reactions are observed from the early stage of development, during embryogenesis and larval period, and into adult stage. Magnetic field affects, among other processes, water exchange in the eggs, embryo heart rate and respiration, directional reactions and spatial orientation. The few papers in this field published so far present melanophores morphology and development. Melanophores developing in embryos and in newly hatched sea trout (Salmo trutta m. trutta L.) larvae which had been incubated and kept under optimal conditions constituted the material for the study. The effect of static, generated magnetic field of intensity of 1, 3 and 5 mT on melanophores of sea trout embryos and larvae was studied. The control setting was kept under geomagnetic field. The appearance of melanophores in the trout embryos exposed to magnetic field was delayed. The number of melanophores was smaller, and the movement of melanin within the melanophores, visible as aggregation of pigment in the cells. Static magnetic field of relatively low intensity influences the reaction of melanophores of developing trout embryos and newly hatched larvae. Most probably, magnetite (Fe3O4) compounds, detected in many fish species, mainly migratory fishes such as trout, are responsible for such behaviour of melanophores.HighlightsStatic magnetic field delays the appearance of melanophores in the trout embryos and larvae.The largest aggregation of melanin in melanophores was found in larvae incubated in a 5 mT magnetic field.The largest number of melanophores was found in the embryos incubated in the geomagnetic field.
Background. The stocks of cod, Gadus morhua Linnaeus, 1758, have been declining within recent decades and the Baltic Sea is one of the most affected areas. The latter body of water with its low salinity, pollution, and vast areas of demersal hypoxia is particularly vulnerable. Areas of natural spawning are scarce and the reproductive output of cod has been irregular and more and more limited. One of the proposed solutions for this problem might be an artificial reproduction.  One of such areas has been the Gdańsk Deep, but the number of potential brood fish is relatively low, which makes the eggs and sperm poorly accessible. The aim of the presently reported study was to conduct spawning and egg incubation under controlled conditions to obtain viable hatchlings and to monitor the embryonic development of cod originating from the area of the Gdańsk Deep. Materials and methods. The parental fish specimens were obtained during commercial trawl catches. The eggs were fertilized artificially at the field laboratory using filtered brackish sea water with salinity of 15‰, and then were incubated at a constant temperature of 8 ± 0.5°C. Eggs and larvae development, and larvae beginning exogenous feeding were observed under a stereo microscope, and photographed regularly to determine the sizes of the eggs and larvae and to document the results of the experiment. Results. The mean percentage of fertilization of eggs was 70%. Hatching began 236 h after fertilization, and the newly hatched larvae comprised 30% of the initial stocking density. The mean length of the larvae was 3.95 mm. The cod larvae began exogenous feeding before the yolk sac was fully absorbed. Conclusion. Artificial reproduction with gametes obtained from cod spawning in the Gdańsk Deep is possible, and the fertilization rates obtained were similar to those achieved with cod from the Bornholm and Gotland basins. Therefore, our results also show that cod spawning in the Gdańsk Deep can be suggested as a model species for further research.
Oxygen uptake and carbon dioxide release by rainbow trout (Oncorhynchus mykiss Walb.) embryos exposed to constant magnetic fields of 5 and 10 mT (oxygen uptake and carbon dioxide release) and 50, 150, and 300 mT (oxygen uptake) were measured. The data were compared with those recorded in embryos developing under natural magnetic field (control). The magnetic fields tested were found to stimulate respiratory processes in the rainbow trout embryos as shown by a significantly increased oxygen consumption, particularly during periods of intensified morphogenesis. Exposure to 5 and 10 mT magnetic fields resulted in a slightly higher carbon dioxide release, the oxygen consumption being observed to increase as well. The respiratory quotient of the embryos exposed to magnetic fields was slightly higher than that in the control.
Trout (Salmo trutta L.) and rainbow trout (Oncorhynchus mykiss Walb.) embryos developing in eggs incubated in the geomagnetic field are oriented NW-SE. Artificial horizontal magnetic fields of 0.5 and 1.0 mT, i.e., higher than that of the natural one but of the same direction resulted in a changed alignment of the embryos examined. The embryos placed in those artificial fields were aligned N-S and NE-SW. A 90° clockwise rotation of the artificial horizontal magnetic field poles, relative to the geomagnetic one, resulted in embryos′ orientation being changed to N-S and NE-SW.
Background. The effect of the magnetic field on fish egg shells has not attracted major interest of researchers, even though it could have been predicted that such effect may be vital to fish embryogenesis. One of the hitherto-neglected aspects of the magnetic field action of fish eggs are the changes in the egg shell permeability and possible alteration of the process of embryogenesis. Studying this process and learning the associated phenomena may be important in explaining cases of substantial mortality of the embryos. Materials and methods. Fish eggs (Atlantic salmon, Salmo salar L.; sea trout, Salmo trutta L.; and rainbow trout, Oncorhynchus mykiss (Walbaum, 1792) and isolated egg shells, in a custom-made osmometer setups, were subjected to the action of a stable magnetic field (2 mT). The ultrastructure of the egg-shells was studied using a scanning electron microscope (JEOL JSM 6100). Results. Stable magnetic field (2 mT), affecting fish eggs, caused statistically significant increase in the egg-shell permeability to water, in the period of the egg activation (and also less distinct increase during the entire embryogenesis). Conclusion. Weak, stable magnetic field increases egg-shell permeability to water affecting water management processes in fish eggs, during incubation. This phenomenon may have practical implications for fish hatcheries.
Abstract Rainbow trout embryos (Oncorhynchus mykiss) in different development stages were exposed to the influence of a constant magnetic field (5 and 10 mT). An increased oxygen uptake was observed in embryos influenced by the field activity as compared to those which develop in a geomagnetic field. The effect of a magnetic field on the breathing processes of embryos was more pronounced in the periods of an advanced morphogenesis.
Abstract Several rivers that are tributaries of the Oder estuary are inhabited by Salmo trutta L, the most important of which are Ina, Gowienica, and Wołczenica. Both forms of the species, sea trout and resident brown trout, are present. All rivers are traditionally stocked with either sea trout from the neighboring Pomeranian river Rega basin or resident brown trout from various locations. To examine populations in these rivers in terms of genetic structure, genetic diversity, and origin, they were analyzed using 13 microsatellite loci. Relatedness was also assessed for fish stocked in the same year. The obtained genotypes were compared with breeding stocks used for stocking in Poland. The analyses revealed a significant genetic distance between adult individuals from Ina and Rega Rivers and fish caught during electrofishing. Strong kinship relationships were identified in the sampled areas, with high proportions of fish originating from stocking and their dominance in numbers over wild juveniles, primarily in smaller tributaries. Additionally, clear separation in the origin of stocked individuals was observed. Adult trout from Ina and Rega are genetically closer to northern brown trout lineages, providing crucial information for the management and biodiversity conservation of Polish Salmo trutta populations.
