Sablefish have a wide distribution in the Pacific Ocean extending from Mexico to Alaska and through the Aleutian Islands and Bering Sea. Reproduction of wild sablefish populations is thought to occur from winter to early spring but there are very few published accounts monitoring reproduction in wild populations. We are investigating the reproductive cycle of sablefish in populations off the Washington and California coasts at monthly intervals throughout a complete year. Samples are being analyzed from females and males for gonadal maturation using gonadosomatic indices and histology, for reproductive hormone levels and for length/weight and age. This project uses commercial fishing vessels for the experimental sampling platforms to collect samples.