Early-life demographic traits are poorly known, impeding our understanding of population processes and sensitivity to climate change. Survival of immature individuals is a critical component of population dynamics and recruitment in particular. However, obtaining reliable estimates of juvenile survival (i.e., from independence to first year) remains challenging, as immatures are often difficult...

The present study evaluated Se bioaccumulation in four waterbird species (n=206 birds) that breed within San Francisco Bay, California, U.S.A.: American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), Forster's terns (Sterna forsteri), and Caspian terns (Hydroprogne caspia). Selenium concentrations were variable and influenced by several factors, including species...

Predators sample the available prey community when foraging; thus, changes in the environment may be reflected by changes in predator diet and foraging preferences. We examined Forster's tern (Sterna forsteri) prey species over an 11-year period by sampling approximately 10,000 prey fish returned to 17 breeding colonies in south San Francisco Bay, California. We compared the species composition...

Tuna purse seine fishery is a commercial and industrial fishery in the Iranian waters of Oman Sea. An observer programme was conducted to identify the by-catch composition of the tuna purse seine fishery in the Iranian waters of the Oman Sea. Investigations were carried out on board of purse seiner vessel “named Parsian Shila” between September and October 2015. The by-catch was composed of 17 ...

Penguins play important roles in the biogeochemical cycle between Antarctic Ocean and land ecosystems. The roles of emperor penguin Aptenodytes forsteri, however, are usually ignored because emperor penguin breeds in fast sea ice. In this study, we collected two sediment profiles (EPI and PI) from the N island near a large emperor penguin colony at Amanda Bay, East Antarctic and performed stabl...

To investigate the diving heart rate (f(H)) response of the emperor penguin (Aptenodytes forsteri), the consummate avian diver, birds diving at an isolated dive hole in McMurdo Sound, Antarctica were outfitted with digital electrocardiogram recorders, two-axis accelerometers and time depth recorders (TDRs). In contrast to any other freely diving bird, a true bradycardia (f(H) significantly <f(H...

The physiological basis of the aerobic dive limit (ADL), the dive duration associated with the onset of post-dive blood lactate elevation, is hypothesized to be depletion of the muscle oxygen (O(2)) store. A dual wavelength near-infrared spectrophotometer was developed and used to measure myoglobin (Mb) O(2) saturation levels in the locomotory muscle during dives of emperor penguins (Aptenodyte...

In order to determine the rate and magnitude of respiratory O2 depletion during dives of emperor penguins (Aptenodytes forsteri), air sac O2 partial pressure (PO2) was recorded in 73 dives of four birds at an isolated dive hole. These results were evaluated with respect to hypoxic tolerance, the aerobic dive limit (ADL; dive duration beyond which there is post-dive lactate accumulation) and pre...