Fluctuating asymmetry as a bio-indicator for the Florida manatee, Trichechus manatus latirostris
Fluctuating asymmetry (FA) is a condition where individuals in a population exhibit small random deviations from symmetry in otherwise bilaterally symmetrical traits. The degree of FA exhibited is often correlated with individual survivability and/or reproductive success and has been used to assess individual and population health. In this study we assessed whether FA is a good indicator of population health for the Florida manatee, Trichechus manatus latirostris. Our assessment of six bilateral characters indicated that the level of FA exhibited by manatees has not changed significantly over the past century. These data may suggest FA is not a useful tool for manatees or that the characters analyzed were not useful markers. Similarly, animals that died from cold stress did not exhibit higher levels of FA than a control group of animals that died due to the 1996 red tide episode. These data suggest that FA is not correlated with survivability for manatees or that manatees do not exhibit selective mortality based on individual quality.