|De vis- en crustaceagemeenschap van de Westerschelde ter hoogte van de kerncentrale van Doel gedurende het winterhalfjaar 1991-1992|
Maebe, S. (1992). De vis- en crustaceagemeenschap van de Westerschelde ter hoogte van de kerncentrale van Doel gedurende het winterhalfjaar 1991-1992. MSc Thesis. Katholieke Universiteit Leuven. Faculteit Wetenschappen: Leuven. 106 pp.
The abstraction of cooling water at the nuclear power station of Doel, which is located in the Westerschelde estuarium, leads to impingement of fish and crustaceans.The community structure of the brackish water area of the Schelde was investigated by monthly sampling of the impinged fish and crustaceans.Our study consists of two parts.Firstly, we took samples every hour during a 24hour-cycle. The aim of this study was to investigate the influence of light condition (day/night) and tide on the structure of the community.24 species of fish and crustaceans were found in the samples. The most abundant species were Crangon crangon (commin shrimp), Palaemonetes varians (prawn), Carcinus maenas (common shore crab), Pomatoschistus minutus (sand goby), Pomatoschistus microps (common goby), Pomatoschistus lozanoi (lozano's goby), Sprattus sprattus (sprat), Clupea harengus (herring), Syngnathus rostellatus (Nilsson's pipefish), Dicentrarchus labrax (sea bass), Anguilla anguilla (eel) and Gasterosteus aculeatus (3spined stickleback).The data were analysed by univariate and multivariate analysis.These analyses showed us that 4 species were significantly more abundant in the night samples than in the day samples (Anguilla anguilla, Pomatoschistus lozanoi, Sprattus sprattus and Clupea harengus). Syngnathus rostellatus was captured significantly more during daytime. These species probably are characterized by an endogenous activity rhythme.The fish of most species belonged to the same yearclass. However, the populations of Anguilla anguilla and Carcinus maenas seem to consist of more than one yearclass.Secondly, samples were taken every month from september 1991 to february 1992.A few new species were found: Perca fluviatilis (perch), Lampetra fluviatilis (river lamprey), Rhihropanopeus harrisii (dwarf crab), Chelon labrosus (mullet) en Liza ramada (mullet).The number of individuals captured varied between 67/- lOOO m3 in february and 351/1000m3 in november.The multivariate analysis showed that the fish and epibenthic communities were different in the faal and in the winter.The highest density of Crangon crangon, Palaemonetes varians, Carcinus maenas, Syngnathus rostellatus, Dicentrarchus labrax, Pomatoschistus minutus and Pomatoschistus lozanoi occurred in the fall, the numbers of these fish decreased in winter.Only Pomatoschistus microps and Gasterosteus aculeatus were captured more often during the winter months. Some very important species were recorded in the samples. Although Osmerus eperlanus 'smelt) normally lives in unpolluted waters, it was captured a few times at the power plant in Doel. Rhithropanopeus harrisii is a brackish water species that has never been found alive in the Schelde before. In the winter samples 5 male individuals were found.Only little information is available on the fish and crustaceans community in the brackish water area of theSchelde. For the fist time, thanks to the optimalized sampling method, samples could be taken upstream of Bath.
- Fish and crustacean community in the Western Scheldt (Doel nuclear power station) during winter season 1991-1992, meer