Sexing sirenians: Validation of visual and molecular sex determination in both wild dugongs (Dugong dugon) and Florida manatees (Trichechus manatus latirostris)

Aquatic Mammals
By: , and 

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Abstract

Sexing wild marine mammals that show little to no sexual dimorphism is challenging. For sirenians that are difficult to catch or approach closely, molecular sexing from tissue biopsies offers an alternative method to visual discrimination. This paper reports the results of a field study to validate the use of two sexing methods: (1) visual discrimination of sex vs (2) molecular sexing based on a multiplex PCR assay which amplifies the male-specific SRY gene and differentiates ZFX and ZFY gametologues. Skin samples from 628 dugongs (Dugong dugon) and 100 Florida manatees (Trichechus manatus latirostris) were analysed and assigned as male or female based on molecular sex. These individuals were also assigned a sex based on either direct observation of the genitalia and/or the association of the individual with a calf. Individuals of both species showed 93 to 96% congruence between visual and molecular sexing. For the remaining 4 to 7%, the discrepancies could be explained by human error. To mitigate this error rate, we recommend using both of these robust techniques, with routine inclusion of sex primers into microsatellite panels employed for identity, along with trained field observers and stringent sample handling.
Publication type Article
Publication Subtype Journal Article
Title Sexing sirenians: Validation of visual and molecular sex determination in both wild dugongs (Dugong dugon) and Florida manatees (Trichechus manatus latirostris)
Series title Aquatic Mammals
DOI 10.1578/AM.35.2.2009.187
Volume 35
Issue 2
Year Published 2009
Language English
Publisher Aquatic Mammals Journal
Contributing office(s) Southeast Ecological Science Center, Wetland and Aquatic Research Center
Description 6 p.
First page 187
Last page 192
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