Experimental culture of the estuarine ectoproct Conopeum tenuissimum from Chesapeake Bay.

Abstract

1. The pattern and form of colony growth in the ectoproct Conopeum tenuissimum was found to be diet-dependent.2. Poorly nourished colonies were characterized by their straggling shape and low zooid number to generation number ratios. These colonies apparently attempted to maximize substrate covered, facilitating location of a more favorable nutrient regime.3. Well fed colonies were rounded in shape and characterized by high zooid number to generation number ratios. These colonies maximized the number of zooids produced in their already favorable area, creating colony reserves, and preparing for reproduction.4. Initial growth in all colonies was exponential, but after a few days of culture growth, rates varied with food used. The chlorophyte flagellate Dunaliella tertiolecta and the dinoflagellate Gymnodinium simplex were good foods, supporting growth to more than 1,000 zooids and sexual maturation within the 42 day culture period. The chrysophyte flagellate Monochrysis lutheri and Va-12 (an un-named chrysophyte flagellate) proved to be fair foods, supporting moderate growth, but no sexual maturation. The blue-green alga Anacystis marinus, the chlorophyte Nannochloris occulata, and the diatom Cyclotella nana supported little or no growth, while bacterial food did not support growth of Conopeum cultures.5. Combinations of algal food produced good colony growth. A three-species mixture was better than a two-species mixture, suggesting differential yet additive nutritional contributions by each algal species.6. Increased food concentrations supported increased growth only up to a certain concentration. This growth response varied with salinity.