Atlantic Halibut have a relatively slow growth rate and late onset of sexual maturity, with males attaining maturity at seven to eight years old, females at 10 to 11 years, and individuals averagely live around 25 to 30 years old. The oldest to have been caught was 50 years old. The Alaskan Halibut is a batch spawner where females lay anywhere from a few thousand to four million eggs (depending on the size and age of the fish, older females tend to lay only two million in one spawning period). Spawning occurs between December and April near the bottom of the ocean between . The egg size is around 3.0–3.8 mm and the larvae at time of hatching is 6.5 mm. Growth weight is dependent on the density, competition, and availability of food.
