158 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



jut FEB HAH UPR 



Figure 7. — Zooplankton concentration. Average of plankton samples taken at stations 1, 3, and 7. 



Table 1. — Summary of dialysis bag data showing initial 

 and final counts of organisms and final copper content 

 of bags placed in East Lagoon, after addition of ore 



' About 60 percent of the organisms in the bags at Station 4 were dead. 



BARNACLE ATTACHMENT RATE IN EAST LACOON 



rV 



If 



1_ 



\I 



Figure 8. — Barnacle attachment in East Lagoon. 



100 — 

 80 — 

 60 - 

 .0- 

 2 -/ 



AUG 6 - AUG 20 1958 



100 



80 



60 



^ 40 



a 20 



5 



AUG 20- SEPT 2 1958 



•~20 TONS OF ORE ADDED 



L_ 



t- BOp 



z 



UJ 60 - 



o 



Q. 



20 - 

 0. — 



to 



20 



SEPT 23-DEC 31 1958 



-40 TONS OF ORE ADDED 



40 

 20 



20 30 



DAYS IN LIVE CARS 



Figure 9. — Mortality of Littorina irrorala in East Lagoon. 



that the snail could tolerate copper concentrations 

 of 8 jug. at./l. with only temporary minor discom- 

 fort. The mortality rate of this organism for five 

 test periods is shown in figure 9. The snails 

 represented by the August 6 to September 2 

 periods were a generation older than those used 

 in subsequent experiments. We believe increased 

 age was the cause of greater mortality rate shown. 

 The decrease in mortality following the addition 

 of the copper ore indicates that the ore had little 

 or no detrimental effect on this organism. The 

 relatively small increase of the copper concentration 



