Parasitic Copepods on Lobsters


Category 3 (Host Not in Canada)

Common, generally accepted names of the organism or disease agent

Parasitic copepods on lobsters.

Scientific name or taxonomic affiliation

Nicothoë astaci.

Geographic distribution

Orkney Islands, Scotland.

Host species

Homarus gammarus (=vulgaris).

Impact on the host

This choniostomatid copepod attaches to a gill filament by means of its suctoral mouth, pierces the wall of the filament with sharp styliform mandibles and feeds on the haemolymph. It often occurs in groups near the base of the gills. At each moult of the host, attached copepods are shed with the old shell and die, but re-infestation by last-stage copepodids can occur in significant numbers shortly after the moult, before the gills become hard again.

Diagnostic techniques

Gross Observations: Parasitic copepods permanently attached to base of gills. Adult female (1.2-1.7mm body length) with two large lateral expansions or wings (up to 4mm long) on thorax and two oval egg sacs (up to 3 mm long) attached to abdomen. Juveniles of a similar appearance, but without egg sacs and smaller in size. Males not found on the lobster.

Methods of control

No known methods of prevention or control.


Mason, J. 1959. The biology of Nicothoë astaci Audouin and Milne Edwards. Journal of the Marine Biological Association of the United Kingdom 38: 3-16.

Citation Information

Bower, S.M. (1996): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Parasitic Copepods on Lobsters.

Date last revised: Fall 1996
Comments to Susan Bower

Date modified: