Long-term changes in commercial fish catches in Lake Mamry Polnocne (northeastern Poland) on the background of physical, chemical, and biological data
2009
Wolos, A.,Inland Fisheries Institute, Olsztyn (Poland). Dept. of Fisheries Bioeconomics | Zdanowski, B. | Wierzchowska, M.,Institute of Inland Fisheries, Olsztyn (Poland). Dept. of Hydrobiology
Lake Mamry Polnocne, a part of the Great Masurian Lake System in northeastern Poland, is a valuable body of water from environmental, recreational, and economic points of view. The paper evaluates long-term physical, chemical, and biological parameters as well as commercial fisheries data. Nitrogen and phosphorus influx data as well as physical and chemical data indicate that the trophic state of Lake Mamry Polnocne can be described as moderate from 1967 to 2006, making the lake borderline b-mesotrophic and eutrophic. The lake's trophic state increased with time, manifesting itself in an increasing concentration of biogenic substances, decreasing water transparency, and worsening oxygen conditions in the hypolimnion. Changes in physical, chemical, and biological parameters generally corresponded with changes in the commercial fish catches of selected species and groups of species indicative of the process of eutrophication
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