Trematoda | Azygiida
Williams, E.H. Jr. and L. Bunkley-Williams. 1996. (Ref. 359)
Size / Weight / Age
Max length : 17.0 cm TL male/unsexed; (Ref. 359)
Climate / Range
Atlantic Ocean and central Pacific.
This small to very large fluke is unmistakable in the stomach of wahoo; a fleshy worm that varies in size and shape; with extended worms the size of a mans finger and contracted ones about the size of a walnut. Smaller worms: still massive but they are capable of contorting into many shapes. Color: brown to pinkish. 2 suckers: easily seen and are close together on the anterior end of the worm.
Length: 0.85 to 10 cm; Live worms may extend to 17 cm. Significance: The wounds they produce and sheer size must have a negative, if unstudied, impact on big game fishes. They have also been used as biological tags (Ref. 359). Associations: We examined 13 dolphin collected off La Parguera, Puerto Rico, for total parasites. Five of these fish had 2 to 3 of these worms, and thousands of other flukes in their stomachs. However, there was no obvious relationship between these worms and other species of flukes. One worm was found in a 0.1 cm long 0.02 cm wide stomach ulcer of an albacore from Desecheo Island. The relationship between stomach ulcers and stomach parasites in big game fishes is not certain. We have seen injuries to the stomach lining of wahoo caused by these worms, but could not be certain that these were not caused after the death of the host. Host Specificity: Wahoo is the preferred host of this parasite, both by being almost always present, and by achieving a consistently large size in this host. It is a characteristic parasite of wahoo and a primary parasite of Atlantic blue marlin, dolphin, little tunny and possibly other scombrids. Secondary parasite: scombrids and billfishes. New Hosts: Blackfin tuna, frigate tuna and longbill spearfish. Damage to Host: causes wounds by penetrating the stomach lining to feed on blood; and absorb a considerable amount of blood. Few worms occur per host. Usually only 1 or 2 of the worms present in the stomach of a host are very
large. Some mechanism of the parasites or the hosts appears to regulate both the numbers and sizes (Ref. 359). Members of the class Trematoda are parasitic, thus requires a host to survive. Life cycle: Eggs are passed on to the feces of the hosts. Embryos hatch into miracidia and penetrate the tissues of snails where they further undergo three stages: sporocysts (Ref. 833).
IUCN Red List Status (Ref. 114614)
CITES status (Ref. 94142)
Threat to humans
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Estimation of some characteristics with mathematical models
Low vulnerability (10 of 100)