Abstract
Ptychodiscus brevis (Davis) Steidinger, 1979 (formerly Gymnodinium breve Davis, 1948) is present throughout most of the year in eastern Gulf of Mexico continental shelf waters at concentrations of <1,000 cells 1−1 (Steidinger, 1975). Blooms (>1,000 cells 1−1) develop 18–74 Km off the west coast of Florida, usually in late summer or early fall (Steidinger and Baden, 1984). Many of these blooms terminate offshore, but they can be transported inshore where they become established along beaches and in lower reaches of estuaries (Steidinger and Ingle, 1972; Steidinger and Haddad, 1981). There have been only four documented blooms of P. brevis off the Atlantic coast of Florida (Murphy et al., 1975; Roberts, 1979; B. Roberts, Florida Department of Natural Resources, St. Petersburg, FL, personal communication). In all four cases these short-lived blooms were initiated off the southwest Florida coast and were transported from the west to the east coast (in October-November) by the Gulf Loop Current-Florida Current-Gulf Stream system.