Thalassiosira punctigera

History of Spread

Thalassiosira punctigera is a widely distributed diatom, which was first described from the Northwest Pacific in 1886. It is known from both sides of the Pacific (British Columbia and Puget Sound samples taken in 1929), and both hemispheres (Wellington, New Zealand 1962) (Hasle 1983). We have found no information on its fossil history, and Hasle (1983) considers it to be of unknown origin. However, we treat it here as originating from one or both sides of the Pacific, since the earliest records are from this ocean.

Outside the Pacific Ocean, T. punctigera was collected off Brazil and Argentina in 1949-1981 and as a rare form in the eastern Caribbean in 1955-56. It was first collected in European waters in 1978, in the English channel, and became abundant in estuarine waters along the North Sea by the 1980s (Kat 1982; Hasle 1983; Durselen and Rick 1999).

In the NW Atlantic, T. punctigera was first collected by Paul Hargraves (University of Rhode Island) in Narragansett Bay in the 1970s. This diatom was overlooked at the time However, in the 1990s, when this species became more abundant, Paul Hargraves rexamined the earlier preserved samples and found T. punctigera. Subsequently, T. punctigera was identified from samples collected in the Gulf of Maine and Chesapeake Bay (Hargraves 1999; Hargraves 2000).

Chesapeake Bay specimens were collected by Hargraves in the York River in the late 1980s (Paul Hargraves 2000). Based on the species' occurrence and establishment in Narragansett Bay, we are assuming that it is also established in the Chesapeake Bay. However, Harold G. Marshall, Old Dominion University, (Marshall 2000) has not identified this taxonomically difficult species in his samples.

History References - Durselen and Rick 1999; Hargraves 1999; Hasle 1983; Kat 1982; Paul Hargraves 2000; Harold Marshall 2000

Invasion Comments