PARENT SESSION
Oral Session # 25: Invasive Species II: Aquatic Systems.
Presiding: G Rilov
Tuesday, August 5. 8:00 AM to 11:30 AM, SITCC Meeting Room 205.

Why is the bryozoan Membranipora membranacea such an effective invasive species?

Pratt, Marney^*,1, ¹ Duke University, Durham, NC

ABSTRACT- Certain species have life histories characteristics that make them particularly effective invaders. The marine bryozoan Membranipora membranacea was first noticed in New Hampshire in 1987. This species became the dominant epiphyte on laminarian kelps in the Gulf of Maine within 2 years, and has had huge effects on kelp forest communities. Kelps encrusted heavily with M. membranacea tend to get damaged and break more easily, and massive defoliation of kelp beds has been reported as a result. What makes M. membranacea such an effective invader? This species has a high reproductive output, can disperse long distances, is good at colonizing new substrates, and can grow very rapidly. All of these characters can be related to hydrodynamics in some way, which is why it is important to understand how water motion affects different aspects of the life history of M. membranacea. For example, the direction and magnitude of currents largely determine dispersal patterns, local water flow characteristics may help determine settlement choices, and water flow influences food acquisition which in turn affects growth, survival, and reproductive output. My research has focused on the effect of water velocity on food capture success, growth, and survival of M. membranacea. I have found that M. membranacea has a higher ingestion rate, grows faster, and survives longer than the other species I have tested at all of the velocities examined. But the question remains why? I tested some potential reasons why M. membranacea captures food so effectively including how the location, arrangement, and size of the feeding zooids affect overall colony feeding success.

Key words: Membranipora membranacea, bryozoa, ingestion rate, invasive species