ORDER
Echinorhynchida
FAMILY
Pomphorhynchidae
TAXONOMY
Pomphorhynchus laevis (Zoega in O. F. Muller, 1776) Van Cleave, 1924 (nec laeve).
OTHER COMMON NAMES
None known.
PHYSICAL CHARACTERISTICS
Average-sized worms with a long and cylindrical neck. Neck dilated in its anterior part into the shape of a bulb. Females are 0.5–1.1 in (13–28 mm) long. Males: 0.24–0.63 in (6–16 mm) long. Body unarmed and most often orange. Cylindrical proboscis with 18–20 longitudinal rows of 12–13 hooks each. Short lemnisci. Two testes in tandem. Six cement glands.
DISTRIBUTION
HABITAT
Definitive hosts: numerous freshwater fishes (e.g., sharp-nosed eel (Anguilla vulgaris), common bream (Abramis brama), chub (Leuciscus cephalus), barbel (Barbus barbus), goldfish (Carassius auratus), etc. Intermediate hosts: amphipods: Corophium volutator, Gammarus bergi, G. fossarum, G. lacustris, G. pulex, and Pontagammarus robustoides. Fish for paratenic hosts (e.g., Phoxinus phoxinus).
BEHAVIOR
Not known. Host dietary carbohydrates likely the major energy source. Adults perforate all layers of intestinal wall with their proboscis and thus never change position in intestine. Infected intermediate hosts exhibit photophilic behavior. Cystacanths bright orange, making infected amphipod intermediate hosts more visible to fish predators.
FEEDING ECOLOGY AND DIET
Little known. Lipid analysis indicates neck and lemnisci function in lipid absorption and storage.
REPRODUCTIVE BIOLOGY
Larvae mature in intermediate hosts within several weeks. Gravid females in fish intestine carry immense numbers of eggs. Once released in water, spindle-shaped eggs appear to be diatom-like.
CONSERVATION STATUS
Not listed by the IUCN.
SIGNIFICANCE TO HUMANS
Not pathological to humans. Possible economic effect by affecting fingerling development in aquaculture conditions.
