| Increases in oceanic shipping are a global phenomenon, and a leading cause of concern for marine animal welfare. While it may be difficult to assess the effect of boat traffic on all species in all contexts, it is vital to report anthropogenic impacts where longitudinal data is available, and doubly so where a dearth of information exists. The purpose of this study is to describe how dolphin behavior changed in the presence of boats in the Mississippi Sound between 2006 and 2012, and more specifically, to detail how different boat types impacted dolphins' behavioral states. This study is unique in its capacity to assess the effect of all major boat types in a given area. Common boat types in the Mississippi Sound were operationally defined as sailboats, recreational boats, fishing boats, shrimp boats, shipping boats, ferries, or patrol boats. Behaviors were grouped into nine behavioral states including feed, social, travel, mill, with boat, rest, other, underwater, and not found. Behavioral states were recorded via an instantaneous scan sampling method. Mixed multivariate analysis of covariance (MANCOVA) tests determined that there was no statistical difference between behavioral states before and after boat events, when boat types were collapsed. However, when boat types were included in analysis, they affected dolphin behavior in significantly different ways. This thesis contributes to the field of difficult-to-assess indirect effects of boat traffic, and provides incentive for researchers to perform inclusive boat traffic surveys in future studies. |
