Experimente zum Einfluß von Sauerstoffmangel auf die Biologie zweier Fischarten der Ostsee (Gadus mohua L. und Scophthalmus maximus L.)
Experiments were carried out to investigate the influence of low oxygen on growth, feeding and food conversion of juvenile cod (G= 6.5-55.8 g) and juvenile turbot (G= 3.4-18.0 g). The fishes were kept for 6 1/2 weaks in 140 l rectangular tanks supplied with Baltic Sea water. Oxygen levels were set t...
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| Format: | Thesis |
| Language: | German |
| Published: |
1994
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| Online Access: | https://oceanrep.geomar.de/id/eprint/52712/ https://oceanrep.geomar.de/id/eprint/52712/1/Dipl.%201994%20Goergens,%20K.pdf |
| Summary: | Experiments were carried out to investigate the influence of low oxygen on growth, feeding and food conversion of juvenile cod (G= 6.5-55.8 g) and juvenile turbot (G= 3.4-18.0 g). The fishes were kept for 6 1/2 weaks in 140 l rectangular tanks supplied with Baltic Sea water. Oxygen levels were set to 40, 57, 74 and 90% saturation. Salinity was between 14.8-15.6. The water temperatures declined from an average of 15.6°C to an average of 11.1°C during the experimental period. The fishes were fed three times a day ad libitum with pellet food. Growth, feeding and food conversion of cod remained almost constant at DO levels of 70 and 90%. At DO levels below 60% a steep decrease of growth, feeding and food conversion was observed. Turbots also showed a weak dependency for growth, feeding and food conversion at declining oxygen levels. However, no critical oxygen level could be established. The critical oxygen level for turbots is expected below 40% saturation. Juvenile cod are more sensitive to low DO levels than Juvenile turbots. Poss1ble effects of oxygen depletion in the Baltic Sea on the development of juvenile cod and turbot are discussed as well as the consequences for the biomass of the Baltic cod stocks. |
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