Subsequent experiments(Blaxter 1953) showed that spring-spawning herring sperm frozen in 12.5% glycerol in diluted sea water (1 part distilled water to 4 parts sea water of salinity 3.4%) held at -79 C was viable after 6 months when thawed and used to fertilize fresh eggs from an autunun- spawning female. Femilization rates of 80 to 85% were obtained but no attempt was made to rear the fertilized eggs. Unfertilized eggs did not survive this cryopreservation treatment.Later, Hempel and Blaxter (1961) reared larvae from a cross between Scottish male herring and German female herring where the Scottish herring sperm had been cryopreserved for 6 wk and was used to fertilize untreated fresh German herring eggs.