Background:

The Monterey sardine Sardinops sagax (Jenyns, 1842), is one of Mexico’s most valuable fishing resources. The feeding habits of this sardine (filter feeder) make it an adequate host for different helminthic parasites.

Goals:

To determine the helminthological load of the Monterey sardine, S. sagax, in the coastal waters of Baja California.

Methods:

Samples of S. sagax landed by the sardine fleet stationed at Puerto del Sauzal, Ensenada, Baja California, were analyzed during the winter-spring and summer-fall.

Results:

We found three species of trematodes: Miosaccium ecaude, Parahe miurus merus (= P. noblei), and Bucephalus sp.; two species of nematodes: Anisakis sp. and Hysterothylacium sp.; and cestodes belonging to the Tetraphyllidae family. During the two sampling seasons, trematodes had the highest prevalence (100%). The prevalence and intensity of the helminthological load was higher in the winter-spring season.

Conclusions:

Of the parasites found, the metacercariae of the Bucephalussp.trematode are a potential parasitic risk to tuna, while the Anisakis sp. and Hysterothylacium sp.nematodes are also transmitted to tuna and can cause zoonosis. These findings are the first parasitological information of the Monterey sardine in Mexico and the first record of Bucephalus sp. in S. sagax. This information provides a baseline for further pathological and epidemiological studies of this species of commercial importance and is crucial for the fishing and aquaculture industry.