In 1997, a mark-recapture investigation was conducted to assess Arctic grayling Thymallus arcticus in Piledriver Slough, near Fairbanks, Alaska. The timing of the investigation corresponded to the period following spring breakup of the slough, at the time of spawning. A total of 820 Arctic grayling were captured with backpack electrofishing and hook-and-line gears, marked, and subsequently released between May 12-16. Following a seven-day sampling hiatus, 994 Arctic grayling were captured using the same methods, in the same areas, and examined for marks, yielding 151 recaptures. An estimated 8,660 (SE = 1,202) Arctic grayling > 150 mm FL were present during the sampling period. The 1997 stock was characterized by a high proportion age-4 and age-5 fish. Densities of Arctic grayling have continued to remain at high levels (627 fish per km), even though beaver dams have blocked migrations to headwater areas and reduced the total area of habitat by as much as 52% for the past five years and may have lowered the population carrying capacity. The estimated survival between 1996 and 1997 was 57%, which indicates the catch-and-release regulation imposed since 1993 may have lowered the overall annual mortality levels. Exploitation was estimated from estimates of catches and probability of hooking mortality and ranged up to 18%, which supports catch-and-release regulations.