Walleye eggs were harvested at the mouth of the Tamarac River as early as 1927 and sent to the State Hatchery at Redby until the Waskish Hatchery, built in 1941 as a Works Progress Administration project, began hatching them locally; the last harvest there took place in the spring of 1979. The hatchery was not built or operated to sustain the Red Lake walleye population, because natural reproduction in Red Lake was more than adequate. Instead, walleye hatched there were used to stock other waters in Minnesota and were also shipped throughout the United States. In spring, spawning walleye ran up the Tamarac River and were briefly trapped for stripping, with mature females first spawning at about 15-17 inches or 5-6 years of age and faster-maturing males at about 4 years. Fish culturists stripped eggs and sperm from ripe fish, held unripe females in cribs for 1-3 days until ready, then mixed sperm with eggs, with most fertilization occurring in the first 15 seconds after water activated the sperm. Because walleye eggs are naturally adhesive, hatchery workers coated them with bentonite to remove that adhesive, then washed and water-hardened them until they became durable enough for transfer to hatchery jars. At Waskish, 4 batteries of 120 jars each could hold about 120,000,000 eggs, with each jar containing about 2 quarts or 250,000 eggs; once full, excess eggs were sent to other hatcheries. Water flow through the jars oxygenated and gently rolled the eggs during incubation, and after hatching the fry moved with the water into metal tanks, where they could survive for up to three days on their yolk sacs before being stocked into lakes or rearing ponds. By using a small portion of a lake’s eggs in a controlled environment, hatchery methods substantially improved hatch rates and created surplus fry for lakes lacking natural reproduction, while returning part of the fry to the parent lake produced a significant net gain; because egg volume at this site reached hundreds of millions, fry returned to Red Lake was also very high.