Clavella perfida

From Fish
Clavella perfida parasitizing on the gill of Alaska pollack.
C. perfida from Alaska pollack. Note the 2 egg sacs.

Clavella perfida is a copepod parasite that infects the gills of marine fish.

It has been reported in the Alaska pollack (Theragra chalcogramma). Clavella perfida possesses 2 egg sacks. It attaches to the gill filament by a bulla. Only a female can be visually observed.

Parasites (5-10 mm) are visually observed in the gill filaments. Its pathogenicity to host fish is low[1].

Since this parasite is not infectious to human, it is harmless in food hygiene.

C. perfida can be readily differentiated from Haemobaphes diceraus parasitizing the gill of Alaska pollack, because the latter is larger and has a long neck extending to the host’s bulbus arteriosus.


  1. Katakura, S., Y. et al (2004) Influence of the parasitic copepod Haemobaphes diceraus and Clavella perfida on growth and maturity of walleye pollock Theragra chalcogramma. Nippon Suisan Gakkaishi 70:324-332