부산대학교 도서관

High temperatures appear to shorten and low temperatures lengthen the incubation period of pink salmon (Oncorhynchus gorbuscha) eggs. The fry migrate to sea during spring when the yolk sac is almost completely absorbed. There is no significant difference from year to year in qualitative description or in certain countable physical characters. Migration is usually swift and vigorous. The effect of light is demonstrated by the fact that movement is limited to the hours of darkness and slowed by direct moonlight. Rainfall does not initiate migration but causes fry already in motion to proceed more quickly. Small temperature variations have little effect. Oxygen content and pH of the water vary coincidentally with rainfall.