Meeting Abstract
It has recently become apparent that polyandry – females mating with multiple males in one breeding season – is prevalent among the elasmobranchs (sharks, skates, and rays). This often leads to multiple paternity, or individual broods being sired by multiple males. As opposed to the clear advantages of polygynous mating to the male, the adaptive advantage of polyandry to the female or her brood is not clear. Some theories include female bet-hedging, trading up, or increased genetic diversity in the overall population. Alternatively, because injuries to the female are probable during mating events, it may simply be safer for her not to resist – a theory known as convenience polyandry. We are using polymorphic microsatellite markers to determine the frequency of multiple paternity in a small coastal shark of the Northern Gulf of Mexico (GoM), the finetooth shark (Carcharhinus isodon). This species has shown evidence of co-occurring annual and biennial reproductive periodicity in the Northern GoM population. We will compare the frequency of multiple paternity between these two subsets in order to determine if the rate is impacted significantly by long-term sperm storage and/or mate encounter rate. This will be the first study of its kind on C. isodon, allowing for comparison to other Carcharhinids to help determine how life history characteristics can impact mating behavior. This information is essential for forming effective management plans for species that are impacted by human activity.
