Family Bosminidae

Bosmina (Bosmina) longirostris (O. F. Muller, 1785)

Bosmina longirostris

B. (Bosmina) longirostris was abundant in lakes throughout the eastern regions of the study area. Samples were collected, from May to December, at depths of 50 m to the surface, primarily from the limnetic zone. Water temperature ranged from 6° C to 23.5° C, and conductivity 25 to 625 mS/cm. Occurring from pH 4 to 9 (Berzins and Bertilsson, 1990), it was recorded at pH 7.5 and 8.25 from Star Lake and Mabel Lake respectively. Tolerant of a wide range of water chemistry, temperature and lake morphometry (Carter et al., 1980), B. (Bosmina) longirostris is abundant in lakes and ponds worldwide. Due to its small size, this planktonic species is generally a dominant member of the zooplankton in lakes with increased fish predation (Berzins and Bertilsson, 1990; Brandlova et al., 1972; Dodson and Frey, 1991; Sanford, 1993). Larger zooplankton species tend to be preyed upon more readily by planktivorous fish because they are easier to see and provide more nutrients.

Collection Localities: Osoyoos Lake 993-95-1, 994-76-1; Okanagan Lake, Squally Point 994-80-1,994-82-1, 994-86-2; Okanagan Lake, Mission 994-84-1; Peachland Lake 992-79-1; Okanagan Lake, N of Kelowna 994-87-1; Okanagan Lake, Lambly Creek 994-77-1, 994-83-1; Aberdeen Lake 983-74-2; Kalamalka Lake lagoon 995-70-3; Cools Pond, Vernon 995-69-2; Peter Hope Lake 983-937-1,983-938-1; Mabel Lake 994-205-7; Shuswap Lake 976-1204-2,994-150-3; Paul Lake 983-928-1, 983-929-1; Mara Lake 995-95-4; Little White Lake 994-148-2; White Lake 994-147-8; Caribou Lake 983-255-4; East Barriere Lake 994-219-7; Phinetta Lake 994-165-2; Lac des Roches 994-170-7; Star Lake 994-229-5.

Bosmina (Eubosmina) longispina (Leydig 1860)

Although keys and descriptions of this species indicate and there is no distal pecten on the postabdominal claw of this species postabdominal claws of specimens examined have a row of very fine spinules distally, visible under high magnification. This species has gone in and out of synonomy with Bosmina (Eubosmina) coregoni. a species that is not known to occur in western North America. Brooks (1959) illustrated this species as B. coregoni and also indicates fine distal spinules on the claw. Not as common as B. longirostris.

Collection Localities: Caribou Lake 983-163-7; Birch Lake 994-225-2; Phinetta Lake 994-165-2, 994-168-2; Lac des Roches 994-170-7.

Cladocerans of the Thompson-Okanagan Region  
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