Studies on the invasive ascidian Didemnum vexillum and the Long Island Sound Benthic Mapping Initiative

  • 10/29/2013 | 4:00 PM – 5:00 PM
  • Location: Druckenmiller Hall, Room 020
  • Event Type: Meeting

Lauren Stefaniak, Department of Marine Sciences, University of Connecticut

Over the past 40 years, the colonial ascidian, Didemnum vexillum, has spread from its native Japan to many temperate coastal regions of the world. Reproduction of daughter colonies in D. vexillum can be sexual, via larvae, and asexual, via long colony lobes or tendrils that easily fragment from the parent colony. Because D. vexillum broods its larvae within the colony matrix, in addition to having the potential to reattach and grow, detached tendrils could also transport competent or near-competent larvae to new locations. Here we quantify aspects of the life history cycle of D. vexillum to determine the relative importance of sexual and asexual pathways to D. vexillum reproduction. We found that the tendril growth form is important to the population biology of D. vexillum by increasing space for feeding and reproducing zooids in a space-limited environment. However, because reattachment of tendrils requires an extended period of contact, tendrils may primarily aid dispersal and establishment of new populations by increasing the number of recruits settling in a single location, potentially resulting in an increased probability of population survival.

The Long Island Sound Seafloor Mapping Collaborative is a multi-institution initiative to create new integrated ecological habitat maps of Long Island Sound. As a part of the Ecological classification group, my project uses a combination of a grab sampler equipped with high-definition video and still cameras, a remotely operated vehicle, drop cameras, and closed circuit rebreather diving to intensely sample benthic habitats. Along with acoustic benthic imaging, modeling of the physical environment, and sediment characterization, these observations will be used to generate habitat maps that managers and stakeholders can use to plan infrastructure in Long Island Sound in a way that minimizes impacts on economically important fisheries and the ecological health of the Sound.