| Spawning takes place in late autumn in cold, clear brooks at 0.5-3 m depth. Females dig nests in gravel and spawn a batch of eggs. Males cover the eggs after fertilization (Ref. 173). Spawning migration into freshwater lasts from June to November, fat reserves are converted into energy and sexual products. Colors change from silvery blue green to brownish or greenish with orange and red mottling. Skin become thick and leathery. Period of spawning lasts for 1-2 weeks, producing 8,000-25,000 eggs. After this, fish are very emaciated, losing 30-40% of prespawning weight (Ref. 35388). Most fish (95 %) die after spawning (Ref. 173). Only 4-6% females spawn a second time. Survivors loose their spawning coloration, hook of males dwindle (Ref. 35388). |