Short-term survival of Steller sea lion (Eumetopias jubatus) pups: Investigating the effect of health status on survival

We estimated survival probabilities for Steller sea lion (Eumetopias jubatus) pups from 3 wk to 6 wk old and from 6 wk to 1 yr at three rookeries in southeastern Alaska. We also investigated the effect of mass, body condition, health variables, and the genetic origin on 3-6 wk survival. Survival differed substantially among rookeries and between sexes, with survival lowest at Hazy Islands, intermediate at White Sisters, and highest at Graves Rocks and survival lower for males than females. Body mass, body condition, and hematocrit were positively related to survival and blood % H2O and haptoglobin level (for females; no relationship for males) were negatively related to survival. Taking predictor variables collectively, sea lion pups at Hazy Islands, which had the lowest survival probability, had the lowest mass, hematocrit, and hemoglobin, and had high levels of blood % H2O, and hookworm infection. Values from Graves Rocks, which had the highest survival, were the opposite of those from Hazy Island (e.g., high mass, body condition, hematocrit, and hemoglobin), while those from White Sisters (intermediate survival) had varying means (e.g., high hematocrit and hemoglobin and low hookworms, but also low body condition); these patterns suggest that physiological factors potentially underlie rookery differences in survival.