RESULTS 
Effect of MONO-585 on Development 
Survival of the zoea of R. harrisii was unaffected by the presence of 1.0 and 
0.1 ppm MONO-585 when the larvae were maintained in salinities of 20 and 35 
ppt (Figure 21-1). In the reduced salinity of 5 ppt, however, total mortality 
within the zoeal stages was observed with a dilution of 1.0 ppm, while survival 
at 0.1 ppm was higher than that observed for either the seawater control or the 
acetone control (Figure 21-1). A concentration of 10 ppm MONO-585 was 
lethal in all three experimental salinities and none of the zoeae developed 
beyond the first stage. 
Megalopa of R. harrisii were affected by the presence of 1.0 ppm 
MONO-585 when combined with a high salinity of 35 ppt but survival of this 
last larval stage was only slightly reduced at 20 ppt (Figure 21-1). There were 
no reductions in survival of megalopa in 0.1 ppm, regardless of the salinity. 
In those experimental salinities in which some development occurred, the 
time required for development from hatching to the megalopa, megalopa to the 
crab, and hatching to the time of Final metamorphosis to the crab, was 
unchanged by the presence of either 1.0 or 0.1 ppm MONO-585 (Figure 21-2). 
The development pattern followed the sequence of four zoeae and one 
megalopa normally observed for R. harrisii and no additional or supernumerary 
larvae were noted. 
As indicated in Figure 21-3, total mortality of megalopa of C. sapidus was 
observed in all series maintained at 5 ppt, including the control. In salinities of 
20 ppt and 35 ppt, 10 ppm MONO-585 resulted in total mortality. One ppm 
reduced survival from 100 percent observed in the controls to 40 percent, 
regardless of salinity, and 0.1 ppm reduced survival to approximately 90 
percent. Time for metamorphosis of the megalopa, from the final zoeal molt to 
the appearance of the first juvenile crab, varied from a mean of approximately 
8 days to 11 days, but the presence of MONO-585 did not appear to be related 
to this variability (Figure 21-4). 
When cultured in 5°C, 24 hour cyclic temperature (20-25°; 25-30°; and 
30-35°: Costlow and Bookhout, 1971) there was no significant change in 
survival of control series or those series of megalopa maintained at 0.1 ppm 
MONO-585 (Figure 21-5). There was, however, some reduction in survival of 
megalopa maintained in 1.0 ppm MONO-585 coupled with all three cyclic 
temperatures. The greatest reduction in survival occurred when the compound 
was combined with a salinity of 35.0 ppt, but this effect was reduced when the 
cyclic temperature was increased to the maximum level of 30-35°C. 
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