The Grande Ronde Basin Spring Chinook Salmon Captive Broodstock Program: What Worked and What Didn't?

The Grande Ronde Basin of Northeast Oregon historically supported multiple large populations of spring Chinook salmon Oncorhynchus tshawytscha.  A steady decline from 1960 through the mid-1990s necessitated development of the Grande Ronde Basin Spring Chinook Salmon Captive Broodstock Program (CBS), which was designed to quickly increase numbers of adults spawning in nature.  The program began with collection of the 1994 cohort in 1995 and ended in 2013.  This presentation provides an overview of our results - what worked and what didn’t.

The CBS generally met its parr collection and survival rate goals.  Male maturation was much younger than expected, with 87% maturing at ages 2 or 3, while 99% of females matured at ages 4 or 5.  Growth was slower than expected and adults were ~35% smaller (at age) than naturally-reared adults.  Bacterial kidney disease (BKD) caused the majority of mortalities.  Fecundity was less than half of that expected and ~20% of all eggs collected were culled to prevent vertical transmission of BKD, causing effective fecundity to be about one-third of that expected.  The CBS successfully contributed to increasing numbers of adults spawning in nature, but disease and growth must be addressed for future programs.