Application of Epidemiological Tools to the Conservation of an Endangered Species: The Plight of Cook Inlet, Alaska Belugas (Delphinapterus leucas)
Dates
Year
2012
Citation
Norman, Stephanie Ann, 2012, Application of Epidemiological Tools to the Conservation of an Endangered Species: The Plight of Cook Inlet, Alaska Belugas (Delphinapterus leucas): University of California, Davis.
Summary
Cook Inlet, Alaska belugas (CIB) (Delphinapterus leucas ) are a genetically and geographically isolated wild stock, residing in the upper Inlet's waters year-round. Four studies were conducted to help evaluate CIB health and survival threats: 1) characterization of hematology and serum chemistry values in Bristol Bay belugas (BBB), a healthy growing population, for comparison to CIB, 2) characterization of hematology and serum chemistry variation patterns from captive belugas over 22 years, to provide methods applicable to wild populations such as CIB, 3) development of a model using anthropogenic and environmental factors to demonstrate CIB population trajectories based on survival and fecundity rates in a simulated population, and [...]
Summary
Cook Inlet, Alaska belugas (CIB) (Delphinapterus leucas ) are a genetically and geographically isolated wild stock, residing in the upper Inlet's waters year-round. Four studies were conducted to help evaluate CIB health and survival threats: 1) characterization of hematology and serum chemistry values in Bristol Bay belugas (BBB), a healthy growing population, for comparison to CIB, 2) characterization of hematology and serum chemistry variation patterns from captive belugas over 22 years, to provide methods applicable to wild populations such as CIB, 3) development of a model using anthropogenic and environmental factors to demonstrate CIB population trajectories based on survival and fecundity rates in a simulated population, and 4) evaluation of fecal pathogens and contributing fecal host sources to surface waters and sediment in areas of upper CI that overlap critical beluga habitat. Results from the first study showed that mean hematocrit, chloride, creatinine, total protein (TP), 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 transaminase, aspartate aminotransferase, gamma glutamyl transferase, and creatinine kinase were significantly higher. In this study, the most striking differences in analyte values for BBB were seasonal, and the analyte value variability noted for age and sex was similar to that seen in other studied wild beluga populations. Based on bloodwork values, BBB appeared to adapt to capture and handling. The BBB bloodwork established useful baselines for further monitoring of this population and future comparisons to BBB. Results from the second study, in which blood analyte variation was evaluated in a captive beluga population, demonstrated that many blood analytes differed based on whale sex and age. For many blood analytes, similar circannual variation patterns were observed across facility location, and seasonal variation was also observed. These findings from a long-term assessment of individual analyte variation in healthy cetaceans agree with previous reports that many blood analytes differ significantly between partitioning factors such as age groups and seasons. Age, seasonality, and sex were important determinants for a majority of the blood analytes, therefore, the variability of these variables should be accounted for when investigating health trends over time. The results from study three demonstrated an efficient and non-invasive method to help determine the magnitude of a stressor that would likely result in the observed decline of the CIB population that could also be applied to other populations. In addition, the results can identify hypothetical causes of the decline and what stressors justify additional resources for study. In the last study, determining fecal pathogen pollution patterns and sources, the most common host source fecal marker was human source, followed by the livestock marker that may also represent large wildlife hosts such as moose and deer. The prevalence of Giardia was greater than that for Cryptosporidium , overall and by matrix type. Salmonella was not detected. Vibrio was more prevalent in sediment than in water for both months. Norovirus was detected in water samples but not in sediment. The most prevalent fecal host source marker detected overall was human, followed by livestock. Human-host Bacteroidales marker prevalence was greatest in water both months, followed by livestock in water and canine and avian in sediment. Fecal coliform counts in surface waters were within Alaska water quality standards, and were 10-100x greater in sediment. In unadjusted regression analyses, water was found more likely to be positive for either protozoal organism compared to sediment. In the final study, the greatest contribution of tested fecal host-specific markers appeared to be from human sources. Exposure of belugas to pathogens in waters where they most often congregate and socialize should be a consi eration. In addition, exposure of marine life and humans to potential fecal pathogens may be influenced by climatic and anthropogenic factors and should be considered when evaluating fecal monitoring programs. (Abstract shortened by UMI.)