Effects of short-term storage of gametes on fertilization of Pacific herring eggs
© Biologischen Anstalt Helgoland 1978
A method is described whereby arrays of samples ofClupea pallasi eggs may be stored during their preparation. The high fertilization potential retained by the eggs during short-term storage allows them to be fertilized synchronously when sample preparation is complete. A variation of the “dry” method of storage retained maximum fertilization potential (80–85%) of the eggs for about 1 hr, and of milt dilution (1∶8 with 17‰ S sea water), about 7 hr. Following dry storage, eggs fertilized in salinities of 0–45‰ showed maximum rates of fertilization in salinities of 10–20‰, and fertilization rates ≥ 50% in salinities of 4.5–42‰. Salinities of fertilization influenced egg diameter, median hatching time, and larval length at hatching in egg samples transferred 21/2 hr after fertilization to an incubation salinity of 17‰ at 7°C. Fertilization rates were higher (90–95%) for eggs stored in 17‰ S at 7°C prior to fertilization. Under such “wet” storage conditions, maximum fertilization pontential was retained for about 2 hr. Highest fertilization rates (95–96%) were obtained for eggs stored and fertilized in salinities of 12–15‰. For the species and the area of origin considered (British Columbia), wet storage of eggs should result in maximum fertilization when the eggs are stored at 4°C for a period not greater than 2 hr prior to fertilization in the 12–15‰ S storage medium.