Maturation of wild adults can be controlled using photo-thermal conditioning. Matured fish can be induced to ovulate using GNRHa implants and repeatedly strip-spawned over several days. GNRHa implants have also been used to initiate tank spawning which will then continue for several months under controlled photoperiod and temperature conditions. Limited production of juveniles has also occurred in fertilized earthen ponds. Small juveniles produced in ponds could be transferred to a dry diet within 14 days.
Juveniles display increasing tolerance with age to low salinity environments.
Fifty day old fish could tolerate 5 ppt salinity while 220 day old fish survived in freshwater. The Yakima Fisheries Project is a multi agency study designed to test the concept that supplementation can utilize fish reared in a hatchery environment to increase the productivity of naturally producing populations of salmon. An experimental hatchery was designed and constructed to facilitate this research. Only wild adult salmon from the Yakima basin will be used as brood stock. Brood stock collection and egg fertilization strategies were developed to maintain genetic diversity.