Ecological studies of a fouling bryozoan Bugula neritina. IV. The effect of low salinity on the early growth of a bryozoan Bugula neritina in the sea and laboratory.

Abstract

Colonies attached to glass slides were suspended in the sea. They were also immersed in low salinity waters once for one or two hours or repeatedly for one, two or six hours once a day to examine the effects of salinity changes on growth. The effect was also examined with a culture method in beakers using water of various salinity (33.7, 31.0, 27.9, 24.1 and 18.1‰), with colonies on glass slides with Rhodomonas as food.Exposure to fresh water for even a short time caused severe damage to the animal, but salinities higher than 9‰ were not injurious for their further growth. Colonies repeatedly exposed to seawater lower than 20‰ will not grow to be a mature colony. If the seawater has a salinity higher than 25‰ they might grow to a mature stage and in salinities higher than 30‰ they grow well.