History and Goals:
Snake River spring/summer Chinook salmon are currently listed as threatened under the Endangered Species Act. Populations of spring Chinook in northeast Oregon, specifically the Grande Ronde Sub Basin have declined sharply during the past five decades. Three streams with threatened spring Chinook populations were targeted for intervention - Lostine River, Catherine Creek, and the Upper Grande Ronde River. Historically the Lostine River supported a large productive Chinook population with an estimated 893 redds in 1957. This number fell precipitously to only 16 redds in 1994. Clearly this population was headed toward extinction unless immediate conservation measures were implemented to assist in restoring the population. In 1995 the Nez Perce Tribe, along with ODFW, CTUIR, and NMFS initiated the Grande Ronde Sub Basin Spring Chinook Captive Broodstock Program. The goals of the program are 1) to prevent extirpation, 2) to maintain genetic diversity and 3) to enhance the natural population.
Rearing and Research:
The process begins with the collection of 500 wild parr from their natal stream, in this case the Lostine River. The parr are raised to smolt stage at Wallowa Fish Hatchery, then transferred to Bonneville Hatchery and Manchester Marine Laboratory to be reared to adult stage. Each fish is identified by a PITT tag and VI tag allowing it to be tracked through out it's life time at each rearing facilities.
Fish transferred to Bonneville are reared entirely in fresh water and those transferred to Manchester are reared in saltwater until maturation when they are then transferred to Bonneville for spawning. The different rearing strategies or “treatments” are being evaluated in order to maximize adult performance. Fish are sampled through out their life span with regard to length, weight, disease and mortality rates. This allows us to evaluate what rearing strategies work best. Each spring at both facilities all fish are sampled for maturity status. Beginning in 2001 the use of ultra-sound imaging was incorporated to determine early maturation and segregation of adults. This is particularly helpful in identifying maturing saltwater reared fish that may benefit from early removal from the salt environment and reduce the incidence of osmoregulatory problems. Maturity sorts continue through August and spawning typically begins in early September. Final length and weights are acquired, fecundity and fertility estimates for each female are calculated allowing for further analysis of rearing strategies. The use of Cryopreservation technology is also a major component of the Captive Broodstock Program. Every effort is made to maximize the genetic diversity of F1 offspring from this program. Any male whose fresh gametes were not incorporated into a spawning matrix for that season is cryopreserved and stored at the Bonneville facility with a duplicate inventory at the University of Idaho. We regularly use these gametes especially in the early and late portions of the spawning season when fresh males maybe limited.
The Fruits of Our Labor:
Eggs are incubated at Oxbow Hatchery and transferred to Irrigon Hatchery at eye up. At Irrigon they are raised to parr and then transferred to Lookingglass where they are reared to smolt stage. From Lookingglass the smolts are transferred to their natal streams for acclimation and release.
Finally we are back where we began, in the natal stream of their beginning. In the spring of 2000 approximately 35,000 smolts were acclimated and released. That number has grown significantly with each successive year of the program.
The year 2002 marked the return of the first F1 generation 4 year old adults to their natal stream. Their run timing, size-at-maturity and sex ratios were in close synchrony to their wild counterparts. For several years now captive broodstock progeny have spawned and laid eggs in the gravels of the Lostine River . Their offspring and how they perform will be the true test of this captive broodstock program.
*This project has been integrated into the Lostine River Monitoring & Evaluation Project.