Effects of Lake Productivity on Density and Size Structure of Pelagic Fish Estimated by Means of Echosounding in 17 Lakes in Southeast Norway
Density estimation of pelagic fish was performed by means of single beam echosounding in 17 lakes within a period of 34 years, from 1985 to 2018. Surveys were performed repeatedly (two to fourteen times) in five lakes. The density estimates ranged from 34 to 4720 fish/ha and were significantly corre...
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MDPI AG
2021-05-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/21/10/3391 |
| _version_ | 1797534342658916352 |
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| author | Arne N. Linløkken |
| author_facet | Arne N. Linløkken |
| author_sort | Arne N. Linløkken |
| collection | DOAJ |
| description | Density estimation of pelagic fish was performed by means of single beam echosounding in 17 lakes within a period of 34 years, from 1985 to 2018. Surveys were performed repeatedly (two to fourteen times) in five lakes. The density estimates ranged from 34 to 4720 fish/ha and were significantly correlated with total phosphorus concentration. The high density in relatively phosphorus rich lakes (<i>TP</i> > 10 µg/L) was comprised of small fish (<20 cm) and was partly due to the higher number of pelagic fish species. The number of pelagic species varied from one, Arctic charr, in the most elevated and oligotrophic lakes, and whitefish dominated in less elevated oligotrophic lakes. In lowland lakes characterized as mesotrophic or tending to mesotrophy, smelt, vendace, and two to three cyprinids comprised the pelagic fish stock. These fish species predate zooplankton effectively, and species composition and body size of planktonic cladocerans was affected by fish density. Large species of <i>Daphnia</i> were lacking in lakes with high fish density, and body size of present species, <i>D. galeata, D. cristata</i>, and <i>Bosmina</i> spp. were negatively correlated with pelagic fish density. |
| first_indexed | 2024-03-10T11:28:17Z |
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| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-03-10T11:28:17Z |
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| spelling | doaj.art-f1ec206aa9304fbbaf8dab9c2cf7cc132023-11-21T19:30:14ZengMDPI AGSensors1424-82202021-05-012110339110.3390/s21103391Effects of Lake Productivity on Density and Size Structure of Pelagic Fish Estimated by Means of Echosounding in 17 Lakes in Southeast NorwayArne N. Linløkken0Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, N-2418 Elverum, NorwayDensity estimation of pelagic fish was performed by means of single beam echosounding in 17 lakes within a period of 34 years, from 1985 to 2018. Surveys were performed repeatedly (two to fourteen times) in five lakes. The density estimates ranged from 34 to 4720 fish/ha and were significantly correlated with total phosphorus concentration. The high density in relatively phosphorus rich lakes (<i>TP</i> > 10 µg/L) was comprised of small fish (<20 cm) and was partly due to the higher number of pelagic fish species. The number of pelagic species varied from one, Arctic charr, in the most elevated and oligotrophic lakes, and whitefish dominated in less elevated oligotrophic lakes. In lowland lakes characterized as mesotrophic or tending to mesotrophy, smelt, vendace, and two to three cyprinids comprised the pelagic fish stock. These fish species predate zooplankton effectively, and species composition and body size of planktonic cladocerans was affected by fish density. Large species of <i>Daphnia</i> were lacking in lakes with high fish density, and body size of present species, <i>D. galeata, D. cristata</i>, and <i>Bosmina</i> spp. were negatively correlated with pelagic fish density.https://www.mdpi.com/1424-8220/21/10/3391fish speciesspecies characteristicszooplanktonpredationalgaephosphorus |
| spellingShingle | Arne N. Linløkken Effects of Lake Productivity on Density and Size Structure of Pelagic Fish Estimated by Means of Echosounding in 17 Lakes in Southeast Norway Sensors fish species species characteristics zooplankton predation algae phosphorus |
| title | Effects of Lake Productivity on Density and Size Structure of Pelagic Fish Estimated by Means of Echosounding in 17 Lakes in Southeast Norway |
| title_full | Effects of Lake Productivity on Density and Size Structure of Pelagic Fish Estimated by Means of Echosounding in 17 Lakes in Southeast Norway |
| title_fullStr | Effects of Lake Productivity on Density and Size Structure of Pelagic Fish Estimated by Means of Echosounding in 17 Lakes in Southeast Norway |
| title_full_unstemmed | Effects of Lake Productivity on Density and Size Structure of Pelagic Fish Estimated by Means of Echosounding in 17 Lakes in Southeast Norway |
| title_short | Effects of Lake Productivity on Density and Size Structure of Pelagic Fish Estimated by Means of Echosounding in 17 Lakes in Southeast Norway |
| title_sort | effects of lake productivity on density and size structure of pelagic fish estimated by means of echosounding in 17 lakes in southeast norway |
| topic | fish species species characteristics zooplankton predation algae phosphorus |
| url | https://www.mdpi.com/1424-8220/21/10/3391 |
| work_keys_str_mv | AT arnenlinløkken effectsoflakeproductivityondensityandsizestructureofpelagicfishestimatedbymeansofechosoundingin17lakesinsoutheastnorway |