Grande Ronde Basin Spring Chinook Salmon Captive Broodstock Program, 2008 Annual Report.

Abstract

The Grande Ronde Basin Spring Chinook Salmon Captive Broodstock Program is designed to rapidly increase numbers of Chinook salmon in stocks that are in imminent danger of extirpation in Catherine Creek (CC), Lostine River (LR) and upper Grande Ronde River (GR). Natural parr are captured and reared to adulthood in captivity, spawned (within stocks) and their progeny reared to smoltification before being released into the natal stream of their parents. This program is co-managed by ODFW, National Marine Fisheries Service, Nez Perce Tribe and Confederated Tribes of the Umatilla Indian Reservation. Presmolt rearing was initially conducted at Lookingglass Fish Hatchery (LFH) but parr collected in 2003 and later were reared at Wallowa Fish Hatchery (WFH). Post-smolt rearing is conducted at Bonneville Fish Hatchery (BOH - freshwater) and at Manchester Research Station (MRS - saltwater). The CC and LR programs are being terminated, as these populations have achieved the goal of a consistent return of 150 naturally spawning adults, so the 2005 brood year was the last brood year collected for theses populations. The Grande Ronde River program continued with 300 fish collected each year. Currently, we are attempting to collect 150 natural parr and incorporate 150 parr collected as eggs from females with low ELISA levels from the upper Grande Ronde River Conventional Hatchery Program. This is part of a comparison of two methods of obtaining fish for a captive broodstock program: natural fish vs. those spawned in captivity. In August 2007, we collected 152 parr (BY 2006) from the upper Grande Ronde River and also have 155 Grande Ronde River parr (BY 2006) that were hatched from eyed eggs at LFH. During 2008, we were unable to collect natural parr from the upper Grande Ronde River. Therefore, we obtained 300 fish from low ELISA females from the upper Grande Ronde River Conventional Program. In October 2008 we obtained 170 eyed eggs from the upper Grande Ronde river Conventional Hatchery Program. We will attempt to collect natural parr in August 2009. This year 752 fish were removed from the captive population: 629 fish survived to gamete production and 123 fish died from various causes prior to spawning. Growth of the Captive Broodstock fish was similar to previous years. The saltwater fish have grown more slowly than those reared in freshwater. A total of 720 fish were sorted as maturing and 629 (87.4%) of them survived to spawn. We collected gametes from 273 females and 350 males from the 2002-2006 brood years in 2008, using 111 spawning matrices and collected 474,187 green eggs (1,737 eggs/female). All ripe males were spawned and no semen was collected for cryo-preservation. Of the 474,187 eggs collected for the BY 2008 F1 generation, 448,373 (94.6%) survived to the eyed stage. 68,612 (15.3%) were culled from females with high ELISA OD values for BKD prevention. For BY 2007, we collected a total of 477,048 eggs from all three populations and 407,369 (85.4%) reached the eyed stage, while 95,024 eyed eggs (23.3%) were culled for BKD prevention. Eyed eggs were hatched at Lookingglass Fish Hatchery, producing 267,131 fry. As parr, 153,371 fish were coded-wire tagged (CWT). For the 2006 F1 brood year, we collected 177,890 eggs and 149,073 (83.8%) reached the eyed stage. 83,826 eyed eggs (56.2%) were culled at the eyed stage for BKD prevention. 61,044 fry were produced (93.6%), 53,688 (88 %) survived to smolt. There were 54 bacterial kidney disease (BKD) mortalities at BOH and MRS, combined in this reporting period. Overall, there were fewer BKD mortalities in 2008 due to a reduced number of fish coming into the Captive Broodstock Program and a shift away from collecting wild parr to using eyed eggs from low ELISA females from the Conventional Hatchery Program. Unknown causes of death accounted for 32 deaths at MRS and BOH, combined in 2008. We continually examine and modify the operations of the Captive Broodstock Program to make improvements wherever possible. We continue to have difficulty with prevention and treatment of BKD outbreaks and continue to use erythromycin and azithromycin to treat this disease. We are also continuing to investigate other possible treatments and prophylactic measures. To reduce the incidence of BKD in offspring of the Captive Broodstock Program, we continue to allow culling of eyed eggs from females with high BKD ELISA values (generally >0.800 OD units but the cull level varies annually, depending on the distribution of ELISA values, number of eggs collected, and management considerations). We are also using ultrasound to determine maturity and sex of fish early in the maturation process and are now able to determine maturity and sex of most maturing fish in early April. This allows us to transfer maturing fish from saltwater to freshwater at a more natural time, which should improve fecundity and egg quality of saltwater-reared fish.