“…These are, for example, larvae of oysters and crustaceans or fish embryos, which are considerably more sensitive to heavy metals than are the reproductive adult stages. Marine hydroid polyps also respond sensitively to heavy metals (Karbe, 1972;Stebbing, 1976;Fischer, 1978): e. g. Laomedea loveni responds even to cadmium concentrations in the low #g 1-1 range (Scholz et al, 1978;Theede et al, 1979b). However, experimental determination of tolerance limits must take abiotic environmental factors into account, because they may be of importance for in-situ survival, especially in estuaries and coastal areas (Eisler, 1971;Olson & Harrel, 1973;von Westernhagen et al, 1974;Jones, 1975;Rosenberg & Costlow, 1976;Sullivan, 1977;Voyer et al, 1977;Weis & Weis, 1978;Lehnberg & Theede, 1979;Theede et al, 1979b).…”