Progesterone levels in fur seals (Arctocephalus forsteri) are used to predict pregnancy rates and ultimately generate population estimates. However, progesterone levels are difficult to track and predict in the early stages of pregnancy. Researchers believe the increased progesterone from pregnancy comes from the corpus luteum, the placenta, or both. The purpose of this study is to detect pregnant and nonpregant females by creating a standard classifying system of detecting progesterone in early gestation periods and to estimate reproductive failures in the preceding breeding season. Fur seals were captured before implantation with a hoopnet and sedated. The animals were tagged and syringed for blood. Progesterone sampling was every twenty-six
