PRESENCE AND HISTOPATHOLOGICAL EFFECTS OF THE COPEPOD PSEUDOMYICOLA-SPINOSUS IN MYTILUS-GALLOPROVINCIALIS AND MYTILUS-CALIFORNIANUS

The copepod Pseudomyicola spinosus (Cyclopoidea, Myicolidae) was found in the mantle, gills, intestine, stomach, and connective tissue of th e digestive gland of the blue mussel Mytilus galloprovincialis and the California mussel Mytilus californianus from Baja California, northwe stern Mexico. The copepod can move from the mantle and gills to the di gestive gland and vice versa. In M. galloprovincialis, copepod prevale nce was 93% and its number ranged from 0 to 20 (mean, 5) in the mantle and gills and from 0 to 5 (mean, 1.1) in the digestive gland. In M. c alifornianus, copepod prevalence was 43% and its number ranged from 0 to 2 (mean, 0.4) in the mantle and gills and from 0 to 1 (mean, 0.1) i n the digestive gland. In the epithelium of the stomach and intestine of both mussel species studied, the appendages of P. spinosus may prod uce a loss of epithelial cells. Occasionally there was a light increas e of hemocytes at the basal region of the stomach and intestinal epith elia where copepod was attached. In the lumen of the stomach and intes tine copepods may be surrounded by mucus. P. spinosus was also found a mong the connective tissue of the digestive gland, apparently as a res ult of penetration through the wall of the stomach or other digestive organs. A granuloma-like structure engulfing the copepod in the connec tive tissue of the digestive gland was found. This is the first descri ption of histopathological effects of P. spinosus in mussels. (C) 1997 Academic Press.