The Use of the Mortality Rate of Marine Fish Prelarvae for the Estimation of Zinc and Lead Toxicity

The effect of zinc on the prelarvae of the Japanese anchovy Engraulis japonicus and on the sand flounder Limanda punctatissima punctatissima and of lead on the prelarvae of the Japanese anchovy was investigated. The median lethal concentrations and maximum ineffective concentrations for a 96-h exposure were calculated. The maximum ineffective concentrations of metals did not exceed their background levels in Peter the Great Bay (Sea of Japan) but were markedly lower than the maximum permissible concentrations (MPC) set for waters of the seas of the Russian Federation. The prelarvae of the Japanese anchovy and the sand flounder can be useful for evaluation and comparison of the toxicity of pollutants and for the estimation of regional MPC levels for pollutants of marine waters.     

Effect of angiotensin II on transepithelial potential in the isolated perfused flounder (Platichthys flesus) gill

Angiotensin II (Asp¹, Val⁵) perfused through isolated flounder gills inhibited the transepithelial potential by up to 25 per cent at a concentration of 10⁻⁹M. There was no effect on gill haemodynamics and the subsequent response to 10⁻⁵ M adrenaline was normal.     

Biomarkers in fish from dioxin-contaminated fjords

Abstract

The Grenland fjords, southern Norway, have been heavily contaminated by dibenzo-p-dioxins and dibenzofurans (dioxins) over decades through inputs from a magnesium smelter. Despite radically decreased inputs since 1990, there are still high levels of dioxins in both biotic and abiotic components of the fjords. The aim of the study was to establish whether biomarkers’ responses in three fish species, Atlantic cod (Gadus morhua L.), sea-trout (anadromous brown trout, Salmo trutta L.) and flounder (Platichthys flesus L.), could be used to discern the effects in the most contaminated ecosystem, Frierfjord, from the effects in the adjacent, less-contaminated ecosystem, Eidangerfjord. Biomarker responses clearly indicated that the three fish species were affected by dioxin exposure. Phase I responses in cod and trout could be used to differentiate exposure in the two fjord ecosystems. Phase II responses (glutathione S-transferase) in cod and trout similarly indicated a higher dioxin exposure in Frierfjord compared with Eidangerfjord. Results for glutathione S-transferase and glutathione reductase indicated different exposure levels in the two fjords, but also showed seasonal variability, and the results highlighted the need for baseline data for these biomarkers.