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active spawn and post-fish samples of 2000, calculated as 77% and 71%, respectively. These values are similar to the 75% of compact particles observed in the ambient suspended sediment during the active spawn of 2000. The ambient waters of the October post-spawn period have only 51% compact particles in the suspended sediment.

When the data from August and October 2000 settling runs are plotted together the different sizes and behaviors of the two populations are apparent (Figure 4.3). The compact particles are generally smaller, all being <760 /m and tend to exhibit the fastest settling rates with 6% actually exceeding the settling rate of 100 /m quartz sand (8.7 mm s-1). The open matrix floc particles exhibit the largest sizes as indicated by the fact that all particles in excess of 760 /m are identified as flocs that generally settle at slower rates. Note that there are few large flocs in the ambient suspended sediments of both August and October, but upon resuspension of the gravel stored sediment the floc structures increase in number.

Table 4.3 summarizes the data from all available settling chamber runs and provides statistics for the particle populations' size (diameter), shape (sphericity), and density by particle type where possible. The data for the relative abundance of floc and compact particles indicates that in all but the die-off period compact particles dominate both the suspended (ambient) and gravel stored (resuspended) samples. The proportion of floc particles tracked for settling varied between 7% and 35% of the total population. The percentage of flocs exceeded the compact particles only during the fish die-off in August 1996. Once again it is clear that the compact particle sizes are significantly smaller than floc sizes, as shown by viewing both the population means and maximum diameters. The largest sizes occur in the resuspended gravel stored sediments during the fish die-off of 1996. The compact particle population mean during die-off is significantly larger (p = 0.05) than compact particles observed at

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