ROBINSON, N.M.*; WALTERS, L.J.; Univ. of Central Florida, Orlando: Asexual reproduction via fragmentation in the bryozoan Zoobotryon verticillatum

The spaghetti bryozoan Zoobotryon verticillatum (Gymnolaemata) is found in warm water marine environments worldwide. In Mosquito Lagoon (northernmost section of the Indian River Lagoon system), the abundance of drift and attached Z. verticillatum varied greatly throughout the year. Plexiglass surfaces deployed for two-week intervals from May 2001 to May 2002 showed peak recruitment periods in May and August with a latent period (no Z. verticillatum reported) from November through April. To better understand the biology of this species, we examined the probability that small fragments of Z. verticillatum could attach to hard surfaces after being separated from the parent colony by either water motion or predation. We also tested if fragment attachment was dependent upon fragment length and weight. 10, 20, 30, 40, and 50 mm fragments were created in the laboratory, weighed, and placed in compartmentalized plastic boxes that were cable-tied to PVC frames in the Lagoon. The boxes were left undisturbed for 4, 12, or 24 hours. After the allotted time, fragments were recorded as: 1) attached, 2) not attached, or 3) dead. We found that there was a low percentage of attachment at four hours (<10%) and intermediate attachment after twelve hours (27%). However, when left undisturbed for 24 hours 73% of the fragments attached. We found the largest size classes to be the most successful. For example, 40 mm fragments attached 92% of the time and 50 mm fragments attached 82% of the time. Photographic documentation of attachment to plexiglass has also been obtained and future studies will examine the attachment mechanism.