The goal of the present study was to carry out a thorough methodological validation and describe baseline profiles for glucocorticoid hormones (cortisol and corticosterone) in blubber from blue ( n = 77) and gray ( n = 103) whales from the eastern North Pacific Ocean. For each species, we modelled cortisol and corticosterone concentrations in response to life history parameters (age, sex, reproductive status) and season or geo...

Killer whales ( Orcinus orca ) are highly social and occasionally gather in large aggregations that reach 150 individuals. During 338 encounters with Southern Alaska resident killer whales, we collected 1,352 hr of behavioral data to assess the probability of various behaviors based on season, number of pods present, presence of rarely sighted pods, and number of mitochondrial DNA haplotypes present. A binomial generalized lin...

Hormonal biomarkers are useful indicators of mammalian reproductive and metabolic states. The present study validated and applied the use of progesterone and cortisol blubber assays for studies of blue whales from the Gulf of California, Mexico. In a validation study for pregnancy detection, blubber progesterone concentrations were correlated with pregnancy status for four female blue whales: three resighted with a calf the ye...

Cook Inlet beluga whales ( CIB s) are an endangered population residing in Cook Inlet, Alaska. We characterized the calling behavior of CIB s to improve our understanding of sounds produced by this population. Bottom‐moored hydrophones were deployed at Eagle Bay in summer 2009 and at Trading Bay in summer and winter 2009. CIB sounds were qualitatively analyzed and categorized as a whistle, pulsed call, or click train. A total...

We examined the effects of maternal buffering in free‐ranging Pacific harbor seal pups during capture and handling research procedures. We predicted that pups held with their mother would benefit from social buffering and exhibit lower cortisol concentrations resulting from capture and handling than dependent pups caught without their mothers and weaned pups. We expected that pups captured with their mother that experienced a...

Three adult captive Steller sea lions (SSL; two females, one male) housed in Alaska were longitudinally sampled for organochlorine contaminant (OC) analysis in both blubber ( n = 19) and blood ( n = 69) over a 2 yr period (March 2001 to March 2003). Blood OC concentrations were similar between individuals, and exhibited significant increases in summer months (July through September) relative to winter (January through March)....

A leading theory for the cause of the decline of Steller sea lions is nutritional stress, which led to chronic high juvenile mortality and possibly episodic adult mortality. Nutritional stress may have resulted from either poor quality or low abundance of prey. The objective of this study was to determine whether we could predict shifts in body condition ( i.e. , body mass or body fat content) over different seasons associated...

The behavioral and predatory patterns of Gulf of Alaska (GOA) transient killer whales ( Orcinus orca ) were studied between 2000 and 2005 using remote video and vessel‐based observations near the Chiswell Island Steller sea lion ( Eumetopias jubatus ) rookery and in the broader Kenai Fjords (KF) region of the northern GOA. GOA transient killer whales were observed on 118 d over the 6‐yr period; the median group size was two (r...