Seasonal and developmental differences in blubber stores of beluga whales in Bristol Bay, Alaska using high-resolution ultrasound.

Diving mammals use blubber for a variety of structural and physiological functions, including buoyancy, streamlining, thermoregulation, and energy storage. Estimating blubber stores provides proxies for body condition, nutritional status, and health. Blubber stores may vary topographically within individuals, across seasons, and with age, sex, and reproductive status; therefore, a single full-depth blubber biopsy does not provide an accurate measure of blubber depth, and additional biopsies are limited because they result in open wounds.

Endocrine changes in harbor seal (Phoca vitulina) pups undergoing rehabilitation.

Rehabilitating pinniped pups are often admitted to care centers as neonates and generally lack maternal investment and are in poor body condition. Upon admittance to a rehabilitation facility, pups are typically fed a milk replacement formula via gavage, which is switched to frozen fish upon weaning. While rehabilitation has been successful in terms of recovery and release, preweaning growth rates in captivity are consistently lower than in the wild.

Seasonal hematology and serum chemistry of wild beluga whales (Delphinapterus leucas) in Bristol Bay, Alaska, USA.

We collected blood from 18 beluga whales (Delphinapterus leucas), live-captured in Bristol Bay, Alaska, USA, in May and September 2008, to establish baseline hematologic and serum chemistry values and to determine whether there were significant differences in hematologic values by sex, season, size/age, or time during the capture period. Whole blood was collected within an average of 19 min (range=11-30 min) after the net was set for capture, and for eight animals, blood collection was repeated in a later season after between 80-100 min; all blood was processed within 12 hr. Mean hematocrit, chloride, creatinine, total protein, albumin, and alkaline phosphatase were significantly lower in May than they were in September, whereas mean corpuscular hemoglobin concentration, monocytes, phosphorous, magnesium, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, γ-glutamyltranspeptidase, and creatinine kinase were significantly higher.

Adverse foraging conditions may impact body mass and survival of a high Arctic seabird.

Tradeoffs between current reproduction and future survival are widely recognized, but may only occur when food is limited: when foraging conditions are favorable, parents may be able to reproduce without compromising their own survival. We investigated these tradeoffs in the little auk (Alle alle), a small seabird with a single-egg clutch. During 2005-2007, we examined the relationship between body mass and survival of birds breeding under contrasting foraging conditions at two Arctic colonies.