Responses of Bugula neritina, an arborescent bryozoan, to the removal of growing tips at different locations within the colony

For colonial organisms physical damage or predation can result in the loss of part of the colony. Although the colony may survive, the loss of part of the colony may alter patterns of growth and reproduction. In this study the response of Bugula neritina, an arborescent bryozoan, to physical damage was tested in three experiments: 1) short term regenerative responses to the removal of zooids from growth tips; ii) growth and reproductive responses to damage imposed at different locations within the colony; and iii) the effects of damage produced by a natural predator, the nudibranch Polycera hedgepethi.

This data set gives the size and reproductive output of B.neritina colonies over a 4 week period in January and February 2000 following 3 damage treatments: i) full tip removal, ii) half tip removal and iii) branch removal and a control or 'intact colony'. Twenty replicate colonies were assigned to each treatment. The damage treatments removed 32 zooid pairs from each colony (approximately 20%) of each colony and were undertaken on colonies in the laboratory and then returned to the field site at Williamstown, Victoria. Size and reproductive output of the colonies were measured once a week, over 4 weeks in January and February 2000. There were no differences in colony size between the damage treatments but colony fecundity was reduced by 70% in the full tip removal treatment.