Poop is underrated in conservation biology.
These smelly samples can tell you what animals are eating, their levels of stress, or whether they are infected by a disease. In a study led by ASLC Research Associate Renae Sattler, funded by the SeaWorld & Busch Gardens Conservation Fund, we’re hoping to learn if poop can also help us find out if female Steller sea lions are pregnant.
The ability to detect and subsequently monitor pregnancy in captive and wild marine mammals is a high priority conservation need. For example, low fecundity has been suggested as a potential driver of the 80% decline in Steller sea lion populations since 1970, and of the continued lack of recovery in parts of their range.
If tools for detecting pregnancy for captive and wild pinnipeds can be developed, not only will resident facilities have a tool to improve health monitoring, animal welfare and herd management, but population managers may be able to quantify pregnancies and enumerate reproductive failures throughout gestation.
Like most things, this is easier said than done. Scientists can’t exactly ask a sea lion to pee on a pregnancy test in the wild, and blood sampling for reproductive hormones, while a common and definitive early pregnancy detection tool, typically requires capture and chemical or physical restraint. Therefore, developing non-invasive methods to detect and monitor pregnancy that eliminate the need for handling are increasingly important.
That is where our study comes in. We want to know if early signs of sea lion pregnancy can be detected in hormones excreted into fecal samples.
So…we are heading into the laboratory!
Earlier this summer, our research fellows started to prepare samples collected from our resident research animals, and now its on to the next step of the process–hormone extraction. At this point, the samples have been freeze-dried to remove moisture, and then sifted to remove any hard parts. This could be sea lion hair, fish scales, or bones from their diet that might interfere with the analysis.
A measured portion of the now powdery poo is separated, methanol is added, and the mixture is gently shaken to extract all the hormones into a solution. At this stage, the resulting liquid ‘supernatant’ is a mixture of any hormones that might be present: estrogen, testosterone, cortisol or, the hormone we’re interested in: progesterone.
Now we are ready for the important next step: analyzing the sample to quantify progesterone levels, and how this changes throughout the year for pregnant and non-pregnant animals.
Stay tuned for the next steps in this study!
Written by: Amy Bishop & Renae Sattler
Funding for this work provided through a partnership with SeaWorld & Busch Gardens Conservation Fund.
Activities conducted under NMFS Permit #18534