Studies on the parasites of Pacific herring (Clupea harengus pallasi Valenciennes): a preliminary evaluation of parasites as indicators of geographical origin for spawning herring

Abstract

A preliminary analysis of parasites as biological indicators for spawning stocks of Pacific herring (Clupea harengus pallasi Valenciennes) occurring in coastal waters of British Columbia and adjacent areas of Washington and Alaska was conducted using the techniques of pattern recognition. Separation of stocks based on three parasites which best served as category separators (Thynnascaris adunca (Rudolphi, 1802) larva; Anisakis simplex (Rudolphi, 1809) larva; and bucephalid metacercariae) using multicategory linear discriminant analysis and k-nearest neighbor analysis revealed good separation for only one locality (Port Gamble, Washington). Re-analysis using three subsets of collections based on geographical area (northern, central, and southern) gave substantially improved classification. Although reliable separation of adjacent stocks of spawning herring could not be accomplished, parasites may be useful in characterizing certain stocks of herring or for separation of stocks taken from more divergent geographical areas.