Biological Tags for Stock Separation in Pacific Herring Clupea harengus pallasi in California

Moser, Mike; Hsieh, Janet

A survey of the parasites of Pacific herring (Clupea harengus pallasi) off northern California identified 1 species of Acanthocephala, 1 species of Cestoda, 2 species of Copepoda, 1 species and 1 family of Digenea, 3 species of Nematoda, and 3 species of Protozoa. From this survey, Lacistorhynchus dollfusi (Cestoda), Parahemiurus merus (Digenea), and Anisakis simplex, Contracaecum sp., Hysterothylacium sp. (Nematoda) were selected as potential tags. Herring were collected in Tomales, San Francisco, and Monterey bays for the following 9 yr and examined for these select parasites. The results suggest that these parasites can be used to distinguish the spawning stocks of San Francisco and Tomales bays. The distribution of the definitive hosts of the respective parasites suggests that the Tomales Bay fish are offshore during the nonbreeding season and the San Francisco Bay fish onshore. The similarity in parasitism between San Francisco Bay and the nonspawning population in Monterey Bay suggests that these 2 populations represent a single stock. Pacific herring were collected from Tomales, San Francisco and Monterey Bays and examined for parasites. From the results the authors determined which parasites could be used to differentiate spawning stocks from one another. Based on the analysis of resident parasites, the authors found that during the breeding season herring from Tomales Bay stay offshore while the fish from San Francisco Bay stay onshore during this period. It was also concluded from the parasite analysis that the herring from San Francisco Bay and Monterey Bay originate fromt the same stock.

Biological Tags for Stock Separation in Pacific Herring Clupea harengus pallasi in California

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