. Bulletin. Science. MACROPARASITES OF PACIFIC SANDDAB 39 n=16 n=33 n=33. Naobranchia occidentalis I Anisakis sp. Lacistorhynchus dollfusi SUMMER FALL WINTER SPRING SEASON Fig. 1. Seasonal mean intensity of 3 common macroparasites infecting Pacific sanddab from White Point, Palos Verdes Shelf, during four seasons: summer and fall 1997, and winter and spring 1998. N is the number of infected hosts per season. Only the mean intensities of L. dollfusi were found to be significantly different seasonally (F3103) = , P = sonally with the highest mean intensity of these parasites occurring
. Bulletin. Science. MACROPARASITES OF PACIFIC SANDDAB 39 n=16 n=33 n=33. Naobranchia occidentalis I Anisakis sp. Lacistorhynchus dollfusi SUMMER FALL WINTER SPRING SEASON Fig. 1. Seasonal mean intensity of 3 common macroparasites infecting Pacific sanddab from White Point, Palos Verdes Shelf, during four seasons: summer and fall 1997, and winter and spring 1998. N is the number of infected hosts per season. Only the mean intensities of L. dollfusi were found to be significantly different seasonally (F3103) = , P = sonally with the highest mean intensity of these parasites occurring in summer (Fig. 1). Mean intensities of Anisakis sp. and L. dollfusi were also compared among 3 age classes of sanddab, but no significant differences were seen (for Anisakis sp. F280 = , P = and for L. dollfusi F290 = , P = ). Seasonal changes in prevalence of fish parasites is common (Chubb 1982) and can be influenced by several factors including temperature and host diet (Williams and Jones 1994). Although temperature data were not collected at the time sand- dabs were obtained for this study, this variable can affect the development of macroparasites like parasitic copepods (Conley and Curtis 1993). Pacific sanddab, a bothid and demersal fish species, is an opportunistic feeder (it readily consumes crustaceans, polychaete worms, razor clams, and juvenile rockfish) that can tolerate disturbed and polluted habitats like that of the PVS (Cross et al. 1985; Rackowski and Pikitch 1989). Crustaceans, like euphausiids, can be a substantial component of the diet of sanddabs (Hopkins and Hancock 1980) and euphausiids can serve as intermediate hosts for Anisakis sp. (Smith and Wootten 1978). Benthic faunal assemblages do vary on the PVS, being in- fluenced by such things as pollution, El Nino, and even strong storms (Thompson et al. 1993). It is possible that seasonal and geographical availability and distri- bution of crustacean prey could account for differences in
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