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Non-Invasive Whale Hormone Measurement

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Visiting a whale habitat and seeing these magnificent creatures up close is a wonderful experience. Free-swimming whales, including Humpbacks, are an eye-catching species for sightseeing. In past years, a huge decline in the number of humpback whales has been observed, mostly due to human impact. Humpback whales have received much attention from wildlife biologists, especially those interested in aiding reproduction. Nevertheless, studying the sex, age, and reproductive status of these animals to aid conservation is a challenge because of a lack of validated sample collection techniques. Novel non-invasive, validated reproduction-monitoring techniques are required to help these beautiful creatures survive and thrive.

A recent study by Kathleen Hunt et al. sought to find an answer to this challenge by exploring a non-invasive method using whale feces as opposed to traditional blood-derived methods. Her group explored practical methods of whale fecal sample collection and its use to screen steroid and thyroid hormones associated with sex, pregnancy stage, and stress levels of humpback whales.

For analysis, more than 50 fecal samples were collected from watery plumes using meshed nets. These fecal plume samples were processed and analyzed for five fecal steroid hormones (progestins [fP], testosterone and related androgens [fT], estrogens [fE], glucocorticoids and mineralocorticoids [fGC], and thyroid hormones).

Fecal samples were screened for progestins using an in-house, lab-derived radioimmunoassay (RIA). Testosterone was screened using two assays; the first assay was an in-house RIA and the second was a commercial colorimetric enzyme immunoassay (Testosterone EIA Kit, K032-H1/H5 from Arbor Assays). The fecal estrogens, glucocorticoids, and thyroid assays were performed using commercially derived RIA formats. All assays were validated by assessing parallelism, precision, and accuracy.

Results from the progestin assays showed fecal progestin levels were considerably increased in pregnant female humpback whales. Androgen assays showed elevated fecal androgens in adult male humpback whales, while thyroid assays were able to quantify hormones in feces and demonstrated seasonal changes and patterns.

In conclusion, the study validated the use of mesh nets for whale fecal samples collection for steroid and thyroid hormone analysis. The results generated valuable physiological, reproductive, and stress-level information on humpback whales that can ultimately be used to help ensure the survival of these beautiful animals for the conservation of marine ecosystems.

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