For species of conservation concern, including lake sturgeon (Acipenser fulvescens), maintaining genetic diversity is critical for successful restoration. Great Lakes lake sturgeon restoration increasingly relies on hatchery supplementation and stream-side rearing facilities that utilize collections of eggs and offspring of early life stages. The number of wild-caught eggs/larvae sampled is not likely an accurate predictor of spawning adult number, nor of hatchery cohort diversity. We used microsatellite loci and likelihood-based pedigree reconstruction to quantify offspring diversity, and the number and effective number of adult lake sturgeon contributing to offspring reared in the Manistee River stream-side hatchery facility in Michigan. Over 10 years (2005–2014) 1129 samples from stream collections of eggs, dispersing larvae, and juveniles were genotyped. Inter-annual variation in estimated mean offspring co-ancestry (Θ 0.013–0.030), numbers of contributing adults (Ns 23–72), and effective number of breeding adults (N^b 17–43) were documented. Combining samples across 10 years we estimated that mean offspring co-ancestry was 0.005, the number of spawning adults (Ns) contributing to offspring released was 326, while the harmonic mean effective number of breeding adults (N^b) was estimated to be 29.5 (lower than 10 times 29.5 for semelparous species). Forty-eight percent of adults contributed one or more offspring in two or more years. Demographic (non-Poisson distribution of adult reproductive success, low annual Ns and repeated spawning) and genetic (low annual N^b, relatedness among offspring within and among year cohorts) features depressed levels of diversity. Implications to species recovery planning are discussed considering low numbers of adults recruiting offspring annually.