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Developing non-invasive biomarkers to monitor threats to Florida manatees
Elizabeth Burgess NEAq
Robert Bonde USGS
Martine de Wit FWC
Charles Deutsch FWC
Margaret Hunter USGS
Rosalind Rolland NEAq
Janet Lanyon UQ
Need to understand stress physiology
• Long-lived, limited dispersal, low reproductive rate– cumulative (sublethal) impacts, population viability
• Threatened species– coastal impacts, severe weather, unusual mortality events
• Herbivorous marine mammal– low-energy forage, seasonal fluctuations
• Poor thermoregulation– seasonal reliance on thermal refugia, cold stress syndrome
Assist monitoring efforts & rehabilitation effortsEarly warning indicators before population consequences
Taking a physiological approach… HORMONES
liver
metabolismconjugation
sample[reflects circulating levels]
excretion
💩💩💉💉
Taking a noninvasive approach… FECES(Larkin et al. 2005)
Hormones in feces
Thyroid hormones
Mineralocorticoids
Glucocorticoids
Estrogens
Androgens
Progestagense.g. progesterone
e.g. estradiol
e.g. testosterone
e.g. triiodothyronine (T3)
e.g. cortisol
e.g. aldosterone
regulate metabolism
stress response
In the lab….Fecal extract by using MeOH to draw out hormones
Enzyme immunoassay uses antibody binding and enzymatic reaction to produce a color change to quantify hormone
Biochemical validationsParallelism testDilution & Std curves parallel
Accuracy testPositive linear relationship
Cortisol AbArbor Assays®
manatee fGC
T3 AbArbor Assays®
manatee fT3
Sex & size class
Overall SIMILAR fGC and fT3 levels across reproductive cohorts
n = 103 manatees
(29) (39) (12) (23)
P = N.S. sex, size class, sex*size class, all P = N.S.
Adrenal activity (fGC) Thyroid function (fT3)
Seasonal variation
LOWER fGC and fT3 levels during winter
(14)(89)
P < 0.001 P = 0.02
Adrenal activity (fGC) Thyroid function (fT3)
Adult MALES have HIGHER fGC and fT3 levelsduring non-winter seasons
Seasonal variation
Adult males, P = 0.001; all Females, P = N.S.
Adrenal activity (fGC) Thyroid function (fT3)
Adult males, P = 0.02; all Females, P = N.S.
(9) (2) (3)(0)(20)(10)(30)(29)
Seasonal variation
WINTER HABITATS:•artesian spring complex• Industrial & 2o warm water site
(14)(89)
Adrenal activity (fGC) Thyroid function (fT3)
Seasonal variation
P = 0.04
LOWER fGC and fT3 levels in manateesoverwintering in artesian spring complex
(89)
P = 0.009
Adrenal activity (fGC) Thyroid function (fT3)
(14)(37)(52)
Work in progress…
• Baseline and critical reference ranges • Full complement of hormone classes (incl. aldosterone)
• Correlation with serum levels
• Chronic cases: cold stress syndromeunusual mortality events
•Toolkit:Health monitoring in wild / rehabilitationMortality event investigation (e.g. Rolland et al. 2017)
Thank you!Funding from Christine Stevens Award, Animal Welfare Institute
U.S. Geological Survey, Wetland and Aquatic Research Center
Florida Fish and Wildlife Conservation Commission
