Cetacean Health Biomarkers
Determining the health of marine mammal populations using physiological biomarkers
In its broadest definition, a biomarker is a measurable indicator of some physiological condition or biological state within an individual animal. We measure them in marine mammal populations to estimate rates of both normal biological states such as pregnancy, sexual maturation, and seasonal reproductive readiness and abnormal conditions like reproductive failure, chronic physiological stress, and poor nutritive health. Together this information, along with other lines of evidence, helps us determine the likelihood that a population of marine mammals is in good health with strong survival and reproduction.
Currently we use hormone analysis of blubber samples to measure biomarkers. Using dart biopsies, we can obtain many blubber samples in a short period of time while minimizing the impacts on the animals. You can think of these biopsies as being like blood samples that you provide your doctor when you are feeling ill. A number of diagnostic tests are run on those blood samples looking for different biomarkers to help determine the cause of your illness. Similarly, we use the hallmark changes in marine mammal hormone levels to help determine the animals’ reproductive states, stress levels, and nutritive conditions. We also gather information from their DNA, RNA, and lipid composition to obtain even greater understanding of their health. Past efforts have examined impacts of strandings, specific types of fishing activity, and pollution, including the Deepwater Horizon oil disaster in the Gulf of Mexico.