AbstractThe reproduction, growth, and variability of the shape of the shell in the gastropod Boreotrophon candelabrum (Reeve, 1848) from Peter the Great Bay (Sea of Japan) were investigated. In aquarium conditions, the mollusks started to lay transparent hemispherical egg capsules in late April at a water temperature of 5.6°C. The females with a shell height of 38–51 mm laid 13–46 egg capsules. The diameter of the base of the egg capsules ranged from 6.0 to 10.1 mm. Each capsule contained from 411 to 1710 eggs with a diameter of 0.204 ± 0.024 mm. In nature, egg capsules appeared in the first half of May and were commonly found from May to the first half of June; a few may be encountered until September. The release of the larvae from the egg capsules into the sea occurred from the second half of May. Mollusks grew most intensively in the first 2 years of life and reached a shell height of approximately 35 mm. The annual shell growth then decreased and at the age of 6 years the mollusks almost attained the maximum size observed in nature. This was calculated by the von Bertalanffy equation: Lt = 61.2 [1 – e–0.5572 (t – 0.4672)]. The shape of the shell of B. candelabrum significantly varied depending on habitat conditions. The habitat given in the species description  was only observed for 17% of the population in the bay.