ISSN:
1438-3888
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Description / Table of Contents:
Summary 1. Eggs of autumn spawning Baltic herring (Clupea harengus L.) were incubated in cadmium-contaminated water (0, 0.1, 0.5, 1.0, 5.0 ppm) at four salinities (5 ‰, 16 ‰, 25 ‰, 32 ‰) in order to evaluate possible changes in toxicity of Cd. 2. Effects of Cd on embryonic survival were found to be dependent on salinity of the incubating water. Deleterious effects of Cd on developing herring embryos were more pronounced in brackish water than in sea water. 3. Embryonic activity, as a measure of viability of developing embryos, decreased in Cd concentrations with decreasing salinity. 4. In none of the trials was egg diameter altered by the Cd content of the incubation water. 5. In all salinities, incubation time appeared to be shortened with increasing Cd content of the test medium. 6. At 5 ‰, 16 ‰, 25 ‰ and 0, 0.1, 0.5 and 1.0 ppm, hatching rate was not significantly altered by Cd. High hatching rates between 85 to 99% occurred in all salinity-Cd combinations. At high Cd levels (5.0 ppm), there was greater survival of embryos at high salinities (32 ‰ and 25 ‰) than at low salinities (16 ‰ and 5 ‰). 7. Percentage viable hatch was unaffected at 32 ‰, 25 ‰ and 16 ‰ S and 0, 0.1 and 0.5 ppm Cd. In low salinities (5 ‰), only 1% viable hatch occurred at 0.5 ppm; in 16 ‰, 61.5 % viable hatch occurred at 1.0 ppm Cd. No viable larvae were obtained in any tests at 5.0 ppm Cd. 8. In all salinities examined, mean total length of newly hatched larvae decreased with increasing Cd concentration of the rearing medium. Relative decrease in mean total length was minimum at 32 ‰ S. 9. In all four test concentrations yolk sac volumes of newly hatched larvae increased with rising Cd concentrations, probably associated with declining embryo activity. 10. The Cd content of eggs was found to be generally higher in lower salinities than in more saline water at comparable Cd concentrations.
Notes:
Kurzfassung Eier des herbstlaichenden Ostseeherings (Clupea harengus L.) wurden in natürlichem und in Cadmium kontaminiertem Seewasser (Konzentrationen: 0,1; 0,5; 1,0; 5,0 ppm Cd) bei verschiedenen Salzgehalten (5 ‰ 16 ‰ 25‰ 32‰) erbrütet. Die Toxizität von Cd wurde im Hinblick auf folgende Kriterien bewertet: Embryoaktivität und Überlebensraten bis zum Schlupf, Veränderungen der Eimembran, Verschiebung des Schlupfzeitpunktes, Unterschiede in den Schlupfraten, Anteil der lebensfähigen Larven und deren mittlere Totallänge sowie Durchmesser der Augen und Gehörkapseln frischgeschlüpfter Larven. Darüber hinaus wurde die Aufnahme von Cd in Abhängigkeit von Konzentration und Salzgehalt im Verlauf der Embryonalentwicklung bestimmt. Die Beeinträchtigung der Heringsembryonen durch Cd war in brackigem Wasser stärker als in unverdünntem Meerwasser. Auch die konzentrationsabhängige Aufnahme von Cd nahm mit sinkendem Salzgehalt des Erbrütungsmediums zu.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01627625
Permalink
