Enhanced sockeye salmon outplanted as part of enhancement projects in the Transboundary Rivers area have their otoliths thermally marked as fry to allow later identification to stocking origin and brood year. Transboundary Rivers (TBR) stock assessment and monitoring projects collect otoliths from both outmigrating sockeye smolts and returning sockeye adults through a variety of projects. The proposed thermal mark recovery project will fund the preparation, interpretation and analysis of these samples, which will provide critical data to stock assessment and enhancement activities; wild/enhanced ratios, scale aging validation, fry to smolt survival, smolt to adult survival, contributions of enhanced fish to returns, straying rates, etc. These data are vital elements of Transboundary stock assessment, enhancement, and fishery management programs. Data are used in enhancement planning and evaluation for multiple stocks, forecasting of returns, annual run reconstructions, and monitoring fishery management performance.