Development and survival of embryos and alevins of the Atlantic salmon, Salmo salar L., continuously exposed to acidic levels of pH, from fertilization

Abstract

Embryos and subsequent alevins of the Atlantic salmon, Salmo salar L., were incubated continuously from fertilization to a time 40 days after hatching at six levels of pH, 6.8 (control), 5.0, 4.5, 4.2, 4.0, and 3.7, at 5–6 °C. Embryos had an LL50 of pH 3.9. The rate of embryonal development was not retarded by these levels. The LL50 for alevins was pH 4.3. Externally deformed alevins were few and not related in frequency to particular levels of pH. Populations of Atlantic salmon will decline and ultimately disappear from freshwater habitats whenever the level of pH approaches 4.5 for an extended period.