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Wetzel, Dana L.; Reynolds, John E., III; Bonde, Robert K.; Schloesser, Ryan W.; Schwierzke-Wade, Leslie; Roudebush, William E.
(detail)
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2019 |
Enhancing reproductive assessments of the Florida manatee (Trichechus manatus latirostris) by establishing optimal time period and inhibin B baseline concentrations.
Endangered Species Research 39: 283-292. https://doi.org/10.3354/esr00972 Aug. 2019.
–ABSTRACT: The Florida manatee (Trichechus manatus latirostris) occupies coastal and riverine habitats that may influence endogenous biological rhythms, including reproductive potential. Inhibin b provides a biomarker of gonadal function and reproductive potential in humans and other eutherian mammals. This study examined the influence of size, sex, and time of year on inhibin B levels in manatees sampled among three habitats with varying degrees of environmental stress in Florida. Inhibin B levels in 38 males averaged (±SE) 4.90 ±0.23 pg/mL; the average level in 31 females was 5.63 ± 0.46 pg/mL. Elevated patterns in inhibin B were exhibited between mid-March and mid-August corresponding to increased mating activity and testicular function, with significant differences in inhibin B levels between male and female manatees (P=0.03) throughout the year. No significant differences in inhibin B were detected between low impacted and higher impacted sampling locations during winter, suggesting the potential influence of environmental stress on manatee reproduction may be best examined between mid-March and mid-August, the midpoint of the reproductively active, non-winter time period. Establishing temporal baselines for inhibin B values may be useful in assessing manatee reproductive status and potential conservation threats, shedding light on fertility potential and enabling future assessment of the effects of stressors on reproduction in Florida manatees.
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Tennant, Rachel; Brady, Beth; Love, Kim; Ramos, Eric; Schloesser, Ryan
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2024 |
Persistent long-term habitat use by Florida manatees at Fort Pierce, Florida from 1997 to 2020.
PlosOne https://doi.org/10.1371/journal.pone.0297636. 7 tabs. 5 figs. Mar. 21, 2024.
–ABSTRACT: To survive cold winters, Florida manatees (Trichechus manatus latirostris) depend on artificial (i.e., power plants) and natural warm water sources such as springs and passive thermal basins. Passive thermal basins can provide critical habitat for manatees for short or extended periods of time. The Henry D. King Powerplant in Fort Pierce, Florida discharged warm water into Moore's Creek until it went offline in 1995. However, it is unknown to what degree manatees continue to occupy this area and how environmental factors influence their occurrence in the creek. To explore this, we examined the habitat use of Florida manatees in Moore's Creek after the shutdown from November 1997 to March 2020 from daily counts of manatees. In addition, we correlated local environmental data (ambient air, temperature, salinity) to assess if Moore's Creek had properties indicative of a passive thermal basin. Results indicated there was not an increase or decrease in habitat use over twenty years in the Creek. The consistent use of Moore's Creek over the study period suggests that this habitat possesses thermal and freshwater resources to support manatee occurrence long-term. These findings provide robust support for the importance of this habitat and passive thermal basins for Florida manatees.
--Review: Ryan Schloesser, Aquatic Mammals, 2004.
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Bibliography and Index of the Sirenia and Desmostylia 