MERCURY CONTENT IN RELATION TO SEX, SIZE, AGE AND GROWTH IN 2 SCORPIONFISH (HELICOLENUS-DACTYLOPTERUS AND PONTINUS-KUHLII) FROM AZOREAN WATERS

Levels of total Hg were determined in the muscle tissue of Helicolenus dactylopterus (mean = 0.29 ug.g-1 +/- 0.025 S.E.; range = 0.04-1.10 ug.g-1) and Pontinus kuhlii (mean = 0.16 ug.g-1 +/- 0.092 S.E.; range = 0.05-0.50 ug.g-1) caught in the Azores between August 1989 and May 1990. Mercury concentrations were related to sex, length, weight, age, growth and condition of both fish species. There were highly significant positive correlations between Hg levels and these variables. In P.kuhlii a significant sex-related difference in Hg levels was found; the rate of Hg accumulation is significantly faster in females than in males and mean Hg levels were higher in females. Relationships describing Hg vs size and age dependence were determined for both species and sexes and patterns and rates of Hg accumulation were discussed in relation to a number of biological and ecological factors with influence on it. A comparison of Hg content of Azorean and Mediterranean populations of H.dactylopterus was conducted and its suitability as an indicator in pollutant monitoring of benthic compartment of marine ecosystems is discussed.