Family Holopediidae

Holopedium gibberum Zaddach, 1855

H. gibberum was recorded from five lakes throughout the study area. Collections were limited to the limnetic zones at depths of 23 m to the surface. A water temperature of 23° C, conductivity of 40 mS/cm and pH of 7.5 was recorded for Star Lake. This acid tolerant species has been previously reported between pH 4.2 and 13.2 (Berzins and Bertilsson, 1990; Sprules, 1975). Although primarily a softwater species, common in lakes with total hardness less than 20 ppm (Stenson, 1973), Carter et al. (1980) recorded H. gibberum from a number of Ontario lakes with total hardness levels between 140 and 180 ppm.

This holarctic species is common in northern and arctic lakes and bogs of Europe and North America. H. gibberum is a planktonic species, but can occur nearshore. Chengalath (1982) reported H. gibberum in five percent of 356 littoral samples collected from sites across Canada.

H. gibberum is identified by a large transparent gelatinous case surrounding the carapace (often damaged during collection) and a uniramous second antennae.

Collection localities: Nickel-Plate Lake 983-812-4; Missezula Lake 983-783-1; Corbett Lake 983-255-3; Aberdeen Lake 983-74-1; Star Lake 994-229-3.

Cladocerans of the Thompson-Okanagan Region  
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