Fluctuating Asymmetry of \u3ci\u3eMenidia beryllina\u3c/i\u3e as a Measure of the Environmental Stress Caused by the 2010 Deepwater Horizon Oil Spill

Fluctuating asymmetry (FA) is often used as an indicator of environmental stress on a population. Stress encountered during development can result in asymmetries in bilateral traits. By quantifying fluctuating asymmetry in Menidia beryllina, FA can be used as an indicator of possible environmental stress linked to the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. The hypothesis states that the levels of FA will be greater in M. beryllina from post oil spill samples compared to pre oil spill samples. Menidia beryllina were used because they are a numerically dominant species found in high wave action coastal estuaries, an area heavily affected by the oil spill. M. beryllina were collected monthly (beginning in May 2011) at Pascagoula River sites where specimens had been previously been collected for various pre oil spill studies. FA was then measured in three bilateral traits: eye diameter, pectoral fin length, and pelvic fin length. Data were analyzed using a two way mixed model ANOVA with side (left and right) as the fixed factor, individual and repeated measurements as factors. This model allows for measurement of FA while controlling for measurement error