We evaluated the traits and survival to release of reconditioned kelt steelhead Oncorhynchus mykiss in the Yakima River (Washington State, USA). From 2001 to 2011, we captured a total of 9,738 downstream‐migrating kelts at an irrigation diversion facility, an average about 27% of each annual wild steelhead return. Captured kelts were reared for 4.5–10 months in an artificial environment, treated for diseases and parasites, and fed both krill and pellets. Surviving reconditioned fish were released into the Yakima River during the peak of the upstream migration of prespawn steelhead. Reconditioned steelhead kelts were predominantly (>92%) female. Annual survival to release ranged from 20% to 62% and averaged 38% over the course of the study, the surviving reconditioned kelts showing increases in FL, weight, and Fulton's K condition factor compared with their preconditioning status. Kelts in good condition and those with bright coloration at the time of collection were more likely to survive than those of poorer status at collection. Postrelease timing of upstream migration by reconditioned kelts was spread over several months and correlated well with the run timing of prespawn migrants upstream. The empirical results we observed demonstrate the potential for kelt reconditioning to provide recovery benefits for repeat spawning imperiled wild populations in highly developed river systems. Received July 17, 2012; accepted March 15, 2013

This study investigated diverse reproductive types in complex mating systems of steelhead Oncorhynchus mykiss. Postspawned steelhead (kelts) were sampled during attempted downstream migration over Lower Granite Dam on the Snake River, U.S.A. Multilocus microsatellite genotypes (14 loci) were used to assign unknown origin, kelt individuals to upstream populations of origin. Results indicated that iteroparity is a life-history trait that remains in several tributaries of the Snake River basin despite strong selection against downstream adult passage because of hydroelectric dams. The largest populations of steelhead in the Snake River, however, were only weakly represented (Clearwater River ¼ 7Á5% and Salmon River ¼ 9Á4%, respectively) in the kelt steelhead mixture relative to the Grande Ronde River (18Á2%), Imnaha River (17Á4%), Pahsimeroi Hatchery (25Á2%) and Asotin Creek (22Á2%). A lack of correlation between population escapement size and kelt proportions (P > 0Á05) suggests that iteroparity was not uniformly expressed across populations, but was significantly negatively correlated with body size (P < 0Á05). Iteroparity may be a valuable source of genetic variability and a conservation priority, especially in years with poor recruitment or in recently bottlenecked populations.

A time‐lapse video system was designed and used to record the migration of adult Pacific salmon at Tumwater Dam on the Wenatchee River, Washington. From 1989 through 1991, the system was evaluated to determine its suitability and usefulness for escapement estimation of three Pacific salmon species, chinook salmon Oncorhynchus tshawytscha, sockeye salmon O. nerka, and steelhead O. mykiss. The accuracy and precision of estimates based on these videotape records were tested. Video‐based sockeye salmon escapement estimates were found to be within 4% of an independent estimate based on the on‐site visual counts made by experienced observers. An among‐observer variance test was performed comparing the counts of five different individuals who examined the same videotape records. Analysis of variance showed no significant differences among the five observers. A test that compared the effect on counts of different time‐lapse recording speeds indicated no significant differences between the two speeds tested, 48‐h and 72‐h modes. The amount of nighttime fish passage, measured between 2000 and 0400 hours, was estimated and averaged for each species over the three study years. Mean values ranged from 6.68 to 16.24%, which indicated that a significant portion of salmon migration at Tumwater Dam occurred at night. An additional test that compared these observations with those of a study of nighttime salmon passage at mainstem Columbia River dams suggested that the ratio of nighttime passage to that of the previous day was similar among study sites. The videotape system appeared to be a useful method for estimating Pacific salmon escapement, which offered several important advantages over on‐site counting. These advantages include improved accuracy, a permanent record of migration, and cost efficiencies that are particularly noteworthy in areas of low escapement. Also, a video record of salmon migration can be used to calculate bounded escapement estimates, and individual specimen identification can be confirmed. The tape analysis process of counting and identifying fish can be automated by means of a computerized image‐processing system.