Sea Lions

The pharmacokinetics of ceftiofur crystalline-free acid (EXCEDE Sterile Suspension, 200 mg ceftiofur equivalents/ml) were determined for the California sea lion (Zalophus californianus). A single dose of EXCEDE was administered intramuscularly at 6.6 mg/kg to 12 wild California sea lions during rehabilitation. The first 10 animals were each assigned to two blood collection time points, with a total of 10 time points at: 6, 12, 24, 48, 72, 96, 120, 144, 168, and 192 hr after administration of the drug. An additional two animals were sampled 1, 2, 3, 4, 5, and 6 hr postinjection. Plasma was separated within 10 min of blood collection and stored at -20 degrees C until analysis. Plasma concentrations of ceftiofur, desfuroylceftiofur, and related metabolites, were determined using liquid chromatography with tandem mass spectrometry (MS). Maximum plasma concentrations of ceftiofur and related metabolites were observed 24 hr postdosing with a mean concentration of 3.6 microg/ml. The half life (60 hr) and area under the curve (270 microg x hr/ml) were also determined. These data indicate that a single dose of EXCEDE at 6.6 mg/kg i.m. would likely maintain a mean plasma drug level >0.6 microg/ml for 5 days and >0.5 microg/ml for 8 days.

The use of novel objects as environmental enrichment devices is a key aspect of many environmental enrichment programs, regardless of whether the animals being enriched are housed in aquaria, zoos, or laboratories. The effectiveness of novel objects as enrichment devices depends on a number of factors, many of which are based on findings from comparative psychology. For example, the literature on habituation predicts that an object that is always in an animal’s environment will be less interesting than a similar object that is available only on an intermittent basis. To test the hypothesis that type of exposure to objects affects the objects’ enriching qualities, we exposed sixteen animals from ten different species to novel objects in two different conditions. In the first condition, animals were exposed to a novel object for a total of 120 min, 60 min at a time on two separate occasions. Approximately three weeks later, the animals were once again given a total of 120 min to interact with the object that they had experienced in the first condition, but the amount of time the object was available per session was much more variable. The results demonstrate that variable presentations are more likely to maintain the enriching qualities of objects, consistent with the literature on habituation.

Studies on population abundance variations at different temporal scales contribute to the understanding on
how these populations change over time and what are the factors influencing those variations. We analyzed daily, monthly
and annual haul-out abundance patterns of South American sea lions (SASL, Otaria flavescens) in 2 breeding colonies of the
north of Chile. Additionally we analyzed the effect of El Niño events on the sea lions’ annual patterns. The abundance of sea
lions in Punta Negra (PN) decreased from 1994 to 2011, whereas in Punta Patache (PP) increased, although the number of
pups was proportionately low. Our results indicated a strong effect of El Niño over the abundance of sea lions, especially
for females + juveniles in PN. The haul-out monthly abundance of females and juveniles increased during austral winter
months, whereas adult and subadult males did not show a clear pattern. Finally, the haul-out abundance tended to increase
throughout the day reaching a maximum by late afternoon, especially for females and juveniles. No difference in daily
patterns between breeding and non-breeding seasons for any of the sex/age classes was found. This study shows that the
number of animals in the PP and PN breeding colonies presented annual, monthly and daily periodicities, and that these
periodicities are conditioned by both intrinsic (e.g., breeding period) and extrinsic (e.g., time of day, El Niño) factors. On an
annual basis, our results indicate that even at a local scale, SASL population trends at 2 colonies may be different.

Marine mammals are repeatedly exposed to elevated extra-thoracic pressure and alveolar collapse during diving and readily experience alveolar expansion upon inhalation - a unique capability as compared to terrestrial mammals. How marine mammal lungs overcome the challenges of frequent alveolar collapse and recruitment remains unknown. Recent studies indicate that pinniped lung surfactant has more anti-adhesive components compared to terrestrial mammals, which would aid in alveolar opening. However, pulmonary surfactant composition has not yet been investigated in odontocetes, whose physiology and diving behavior differ from pinnipeds. The aim of this study was to investigate the phosphatidylcholine (PC) composition of lung surfactants from various marine mammals and compare these to a terrestrial mammal. We found an increase in anti-adhesive PC species in harp seal (Pagophilus groenlandicus) and California sea lion (Zalophus californianus) compared to dog (Canus lupus familiaris), a...