Document Type

Statistical Report

Publication Date



The City of Tampa Bay Study Group has noticed high numbers of an anural solitary mogulid tunicate, of an unknown ascidian species, dominating some bottom communities of Hillsborough Bay during the winter. Ascidian concentrations have been found in excess of 4000/me , and lengths have ranged from O.25mm to 20mm for larvae and adults, respectively. Coincident with these high ascidian concentrations, excellent water clarity has been observed, where the bay bottom is visible through water of 2 to 3m depths. Ascidians can filter large volumes of seawater as part of their food gathering process. Although not found in Hillsborough Bay, Phallusia, an ascidian only a few centimeters long, can reportedly filter 173 liters of water per 24 hours.