The seasonal biological surveys of 1971 / John C. Ayers, Samuel C. Mozley, John A. Stewart.

TABLE 7. The common zooplankton Crustacea (16 genera, 21 species).
Max. X of fauna
in collections
1971 1972
Cyclopoid copepods (2 genera, 3 species)
Cyclops bicuspidatus thomasi S. A. Forbes 36 42
Cyclops vernalis Fischer <1 <1
Tropocyclops prasinus mexicanus Kiefer 5 3
Calanoid copepods (4 genera, 7 species)
Diaptomus ashlandi Marsh 22 43
Diaptomus minutus Lilljeborg 8 12
Diaptomus oregonensis Lilljeborg 7 9
Diaptomus sicilis S. A. Forbes <1 2
Epischura lacustris S. A. Forbes <1 1
Eurytemora affinis (Poppe) <1 <1
Limnocalanus macrurus Sars <1 1
Harpacticoid copepods (1 genus, 1 species)
Canthocamptus sp. <1 1
Cladocerans (9 genera, 10 species)
Bosmina Zongirostris (0. F. Muller) 85 85
Eubosmina coregoni (Baird) 19 12
Ceriodaphnia quadrangula (0. F. Muller) 1 <1
Chydorus sphaericus (0. F. MUller) <1 <1
Daphnia galeata mendotae Birge 11 6
Daphnia retrocurva S. A. Forbes 28 16
Diaphanosoma leuchtenbergianwn Fischer <1 1
Holopediwn gibberum Zaddach 10 7
Leptodora kindtii (Focke) <1 <1
Polyphemus pediculus (LinnQ) <1 1
Particular interest is given this survey by the presence of a thermal bar
condition in the Cook area. A plot of surface temperatures places the 4~C
isotherm along the 18-m depth contour (Fig. 2). On another survey date, 2 May
1972, we also encountered a thermal bar condition in the area; at this time
the 4~ isotherm was located along the 25-m contour. On 12 April 1972, stations throughout the survey area had surface temperatures less than 4~, while

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