. The Canadian field-naturalist. 166 The Canadian Field-Naturalist Vol. 105 upstream and downstream of Hope; however, no reports exist of sturgeon spawning areas in British Columbia. The effect of the 1913 slide at Hell's Gate on the Fraser River with respect to limiting sturgeon migration and access to spawning areas has never been investigated, nor has the use of the present Hell's Gate fishway by sturgeon ever been reported. General Biology There are few publications on the biology of White Sturgeon. In the Sacramento River, sturgeon spawn in the spring (Kohlhorst 1976) when the water tempe
. The Canadian field-naturalist. 166 The Canadian Field-Naturalist Vol. 105 upstream and downstream of Hope; however, no reports exist of sturgeon spawning areas in British Columbia. The effect of the 1913 slide at Hell's Gate on the Fraser River with respect to limiting sturgeon migration and access to spawning areas has never been investigated, nor has the use of the present Hell's Gate fishway by sturgeon ever been reported. General Biology There are few publications on the biology of White Sturgeon. In the Sacramento River, sturgeon spawn in the spring (Kohlhorst 1976) when the water temperature is between and °C. Kohlhorst (1976) indicates peak spawning occurs when the water temperature is 14 to 15°C. Specific details of the spawning habitat of White Sturgeon are undescribed; eggs are adhesive (Monoco and Doroshov 1983), and it is likely that sturgeon spawn as do other Acipenser species - broadcast fertilization with the adhesive fertilized eggs adhering to crevices in the substrate. Fecundity is quite high, 180 000 to 590 000 eggs per female or between 7600 to 10 900 eggs' kg female body weight (Doroshov et al. 1983). The eggs of Acipenser transmontanus exhibit amphibian-like holoblastic cleavage and hatch in about 7 days at 15° C. The sac fry start feeding 7 to 10 days after hatch (Doroshov et al. 1983). Growth is quite variable in the wild. Hess (1984) has indicated that the fish reach an average size of 167 cm in 20 years; but the size range at that age is from 133 cm to 185 cm. Approximate comparisons of average growth rates from the Sacramento River in the south to the Nechako River in the north indicates the fastest growth is in the warmer water of the Sacramento and lower Columbia River compared to the lower and upper Fraser River (Figure 5). Growth of cultured sturgeon is much more rapid than in the wild (Figure 5). Margolis and McDonald (1986) record the parasites from juvenile and subadult sturgeon taken in the lower Fraser River. Food of
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