Wirkungen von Rohöl-Emulgatorgemischen auf marine Fischbrut und deren Nährtiere

Abstract

The effects of crude oil-emulsifier mixtures on the larvae ofClupea harengus L. andAgonus cataphractus L. are described. The herring larvae tested had total lengths of 20 to 26 mm; the larvae ofAgonus cataphractus were investigated shortly after their first food intake. Samples of wild plankton from daily catches (used as food during rearing experiments) were also tested. The different dilutions were obtained from the following initial mixture: 20 ml emulsifier “Moltoclar”, 80 ml Irak crude oil, 900 ml stale sea water (∼32 S ‰). Dilutions with the following content of the emulsifier were used: 50 mg/l, 25 mg/l, 5 mg/l, 2.5 mg/l, 0.5 mg/l, 50µg/l, 5µg/l, 0.5µg/l. Lethal concentrations ranged from 2.5 to 5.0 mg/l. Sublethal damages were clearly ascertained down to a concentration of 0.5 mg/l. Irak crude oil alone did not cause damage to herring larvae during the observation period of 4 days.

Zusammenfassung

1. Es wurde die Einwirkung eines Rohöl-Emulgatorgemisches (Irak-Öl/Moltoclar) auf die Larven vonClupea harengus L. undAgonus cataphractus L. sowie auf Wildplankton untersucht.

2. Bei Emulgatorkonzentrationen von 2,5 bis 5,0 mg/l war die Letalitätsgrenze erreicht.

3. Subletale Schädigungen ließen sich bis zu einer Konzentration von 0,5 mg/l deutlich nachweisen.

4. Irak-Rohöl hatte keine schädigenden Wirkungen auf Heringslarven.