Influence of physical and chemical factors on settlement and recruitment of the hydroid Tubularia larynx

Abstract

Field observations using settlement panels, which were carried out in Port Daniel Bay, Bate des Chaleurs, Quebec, Canada, in 1992, showed recruitment by the hydroid Tubularia larynx to be unevenly distributed with depth. Multiple regression on residuals indicated that 2 physical factors, water temperature and light intensity, out of 5 tested explained 45% of the observed variance in the recruitment of T. larynx on the panels. In laboratory experiments, warm temperatures increased settlement significantly. Contrary to field results, light intensity did not seem to influence the settlement of T. larynx in the laboratory. The influence of small scale (