Effects of introduced species on the recruitment of sessile invertebrates.

This experiment was conducted to determine if an established Botryllus schlosseri colony affected the recruitment of sessile invertebrates. Small perspex plates that had been in the field for 8 weeks and then in a laboratory water table were used to test this hypothesis. Treatment plates were scraped of all organisms expect for the B. schlosseri colonies. Control and 'mimic' plates were scraped of all organisms. Mimic B. schlosseri were made from silicone and used to determine if the effects were due to the physical structure of the organism or biological attributes (e.g. post-settlement overgrowth or chemical defence mechanisms). Plates were suspended from Workshops Jetty, Williamstown for 10 days (2nd March to 12th March 2004) before being collected. At the conclusion of the experiment all species found on the plates were counted and identified.