Cook Plant preoperational studies 1970 / John C. Ayers ... [et al.].

TABLE 19. Zooplankton -- Summary table of bag experiments at Bailly,
20 June 1970.
Bag Time Time Elapsed Water Zooplankton/l Live/Dead Means of
filled emptied time volume Alive Dead Ratio/1 Ratios
IA-1 1,055 1,125 30 min 100 1 0.50 0.45 1.11
IA-2 " " " 100 1 0.77 0.82 0.94 1
IP-1 1,113 1,140 28 min 40 1 0.40 1.00 0.40
IP-2 " " " 54 1 0.28 0.56 0.50 0.45
OP-1 1,325 1,355 30 min 80 1 0.96 1.13 0.85
OP-2 " " " 80 1 0.64 1.03 0.62 0
OA-1 1,335 1,410 35 min 50 1 0.88 1.70 0.52
OA-2 50 1 1.42 2.32 0.61 0.57

contents were put through the zooplankton net and the entire collection counted,
there is no question of the reproducibility of aliquot counts involved.
The zooplankton net used was a #5 mesh which did not catch the smaller
zooplankters; the proportions of live and dead represent the condition among
the larger, more damageable, zooplankters.
The highest ratio of live to dead zooplankters was found in the bags of
intake water retained at ambient temperature (IA bags). Plankters in these
bags had been subjected only to natural in-lake damage and that attributable
to bucket-filling of the bags.
The smallest live/dead ratios were found in the bags of intake water
drifted through the plume (IP bags). Plankters in these bags had been subjected
to natural damage, bag-filling damage, and plume temperatures; that fewer
survived this treatment than survived passage through the plant (OP bags) is
unrealistic. It is attributed to too small zooplankton numbers in the bagged
water volumes used. Larger bags containing more zooplankton should provide
more reliable counts.

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