Preliminary Study on Distribution and Abundance of Chaetognaths (Arrow Worms) in the Gulf of Mexico.

The distribution of zooplankton presumably reflect ocean conditions. Chaetognaths (arrow worms) consist of an important zooplankton component and are recognized as a significant trophic link between smaller marine zooplankton, such as copepods, and larger predators, including many commercially important fish species. Arrow worms are raptorial predators which feed mainly on zooplankton and larval fish, which may affect recruitment dynamics of fish. Despite their trophic significance, there is limited information on the distribution and abundance of arrow worms in terms of environmental conditions in the Gulf of Mexico (GoM). In this study, we processed zooplankton samples that were collected using 200 µm vertical plankton nets at inshore and offshore stations in the GoM during spring and summer of 2015. Concurrently, we collected vertical profiles of temperature, salinity and density using a CTD in the spring, and surface temperature, salinity and dissolved oxygen in the summer. Our preliminary results indicate that Sagitta friderici and Sagitta tenius are abundant species in offshore stations. Furthermore, we explore the relationship between arrow worm species abundance and distribution with relation to physical variables in the region. This research will improve our understanding on the abundance and distribution of arrow worms in terms of ocean conditions in the GoM.