Scallop Gill Turbellaria


Category 4 (Negligible Regulatory Significance in Canada)

Common, generally accepted names of the organism or disease agent

Scallop gill turbellaria.

Scientific name or taxonomic affiliation

Unidentified turbellarian.

Geographic distribution

On sea scallops from Atlantic Canada but may have a wider distribution.

Host species

Placopecten magellanicus as well as other bivalves including oysters clams and cockles.

Impact on the host

All observations to date are based on histology and large numbers have not yet been observed (prevalence up to10%, 1-2 per section).

Diagnostic techniques

Histology: Examine transverse sections through gill and palp areas for cross sections through turbellarians characterised by ciliated surfaces. Occasionally found in the stomach or intestine.

Methods of control

No known methods of prevention or control. Managers of areas currently free of these flatworms may wish to prevent their introduction.


Ball, M.C. and S.E. McGladdery. 2001. Scallop parasites, pests and diseases: implications for aquaculture development in Canada. Bulletin of the Aquaculture Association of Canada 101-3: 13-18.

McGladdery, S.E., R.E. Drinnan and M.F. Stephenson. 1993. A Manual of the parasites, pests and diseases of Canadian Atlantic bivalves. Canadian Technical Report of Fisheries and Aquatic Sciences No. 1931, p. 107-110.

McGladdery, S.E. and M.F. Stephenson (unpublished data). Parasites and diseases of wild and suspension-grown sea scallop Placopecten magellanicus from Newfoundland. Atlantic Canadian Association of Parasitologists, Mont-Joli, Quebec, October 1991.

Citation Information

Bower, S.M., McGladdery, S.E. (2004): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Scallop Gill Turbellaria.

Date last revised: December 2004
Comments to Susan Bower

Date modified: