Research on Captive Broodstock Programs for Pacific Salmon, 2003-2004 Annual Report.
- National Marine Fisheries Service
The success of captive broodstock programs depends on high in-culture survival, appropriate development of the reproductive system, and the behavior and survival of cultured salmon after release, either as adults or juveniles. Continuing captive broodstock research designed to improve technology is being conducted to cover all major life history stages of Pacific salmon. We were able to develop an analytical method for optimizing the detection of spawning events in Chinook salmon using EMG signals. The method developed essentially captured the consistently greater frequency of higher EMG values associated with females cover digging immediately following spawning. However, females implanted with EMG tags retained the majority of their eggs, which significantly reduced their reproductive success compared to non-tagged females. Future work will include increased sample sizes, and modified tagging methods to reduce negative effects on reproductive success. Upper Columbia River sockeye salmon exposed to the odorants PEA, L-threonine, Larginine and L-glutamate were able to learn and remember these odorants as maturing adults up to 2.5 years after exposure. These results suggest that the alevin and smolt stages are both important developmental periods for successful olfactory imprinting. Furthermore, the period of time that fish are exposed to imprinting odors may be important for successful imprinting. Experimental fish exposed to imprinting odors as smolts for six or one weeks successfully imprinted to these odors but imprinting could not be demonstrated in smolts exposed to odors for only one day. A 2-3 C reduction in seawater rearing temperature during the fall and winter prior to final maturation had little effect on reproductive development of spring Chinook salmon. Body size at spawning and total ovary mass were similar between temperature treatments. The percentage of fertilized eggs was significantly higher for females exposed to the ambient temperature compared to those exposed to the chilled temperature. However, the percentage of embryos surviving to the eye-stage, total fecundity, and mean egg mass did not differ between treatments. This work is being continued with larger samples sizes and increased duration of temperature exposure. Exercise during the months prior to final maturation had no detectable effects on fertilization success or embryo viability in Redfish Lake Sockeye. Problems with highly variable or low eyed-embryo survival are most likely due to problems with fertilization. Synchronizing spawn timing between males and females may improve gamete fertility, perhaps by making oocyte maturation and ovulation more readily detectable and synchronous within the individual. Improvements in milt production (using GnRHa) and fertilization protocols have apparently increased fertilization success in Redfish Lake sockeye over previous years. Broodstock treatment with azithromycin immediately prior to spawning can protect against acute challenge with R. salmoninarum. Among fish challenged with 10,000 virulent R. salmoninarum cells per fish, progeny of broodstock treated with azithromycin exhibited significantly greater survival than progeny of sham-treated broodstock. Work on the efficacy of antibiotic treatment and vaccination against BKD before and after smoltification in offspring chinook salmon captive broodstocks is ongoing. To date, the long-term study of inbreeding indicates that the potential for anadromous Chinook salmon to respond rapidly to close inbreeding, with adverse consequences for marine survival and, possibly, growth. The effects of inbreeding expressed during early life history do not reveal significant effects. Overall, the results would support recommendations for initiating artificially propagated populations with sufficient, outbred broodstock and implementing carefully monitored breeding practices to minimize rates of inbreeding during a program's duration.
- Research Organization:
- National Marine Fisheries Service
- Sponsoring Organization:
- United States. Bonneville Power Administration.
- DOE Contract Number:
- 00005227
- OSTI ID:
- 900478
- Report Number(s):
- DOE/BP-00005227-4; R&D Project: 199305600; TRN: US200711%%339
- Country of Publication:
- United States
- Language:
- English
Similar Records
Research on Captive Broodstock Programs for Pacific Salmon, 2002-2003 Annual Report.
Research on Captive Broodstock Programs for Pacific Salmon; Assessment of Captive Broodstock Technologies, Annual Report 2002-2003.
Related Subjects
ADULTS
AMBIENT TEMPERATURE
ANTIBIOTICS
BREEDING
COLUMBIA RIVER
EMBRYOS
FEMALES
FERTILITY
FERTILIZATION
GAMETES
JUVENILES
MALES
ODORANTS
OOCYTES
OVULATION
PROGENY
REARING
SALMON
VIABILITY
Pacific salmon - Physiology - Research
Pacific salmon - Breeding - Northwest
Pacific - Research