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t 1 1 t t 1 1 t t 1 11 1 t Morgan Fish Disease Control Center in 1984. Thus the incidence of tape- worm infection was assumed to be zero among fishes in T & F Pond. In West Pond, Asian tapeworm was first detected in squawfish on 2 June 1987. The average number of worms per infected fish was low at that time. However, infection intensity rapidly became quite high (Table 4). Squawfish col- lected during 1988 have not yet been examined for Asian tapeworm, but it can be assumed that infection rates and worm burdens were at least as great as in 1987. The effect of Asian tapeworm on Colorado squawfish is not yet known. However, the literature indicates that this parasite is a dangerous patho- gen, particularly to underyearling cyprinids. Scott and Grizzle (1979) report heavily infected golden shiners (Notemigonus crysoleucas) killed by complete intestinal blockage and occasional bursting of the intestine. Heavy infections may cause blockage, inflammation and perforation of the intestine, generalized emaciation, reduced growth rate, and even death (Hoffman 1980, Pool et al. 1984). Infection rates and severe losses of common carp sometimes reach 100% in German pond hatcheries (Korting 1975). Given the high infection rates and intensities in Colorado squawfish from West Pond, B. acheilognathi should be considered a serious problem for squawfish pond culture. Water Quality. Low dissolved oxygen may have caused some problems for fish in late August. In the central region of the pond, where limnologi- cal data were normally collected, DO dropped to 1.0 mg/L on the bottom, 0.5 mg/L at mid depth, and 1.5 mg/L on the surface (Fig 4). However, in the north corner of the pond, where fish were rising for mayflies, dis- solved oxygen remained between 3-5 mg/L during this time. Thus, squawfish 27