Vol. 53 - Alaska Resources Library and Information Services

little vertical temperature stratification inshore of the 50 m isobath.
The high temperatures on the northern side of Bristol Bay during June
and September were apparently related to warm fresh water moving generally
west from Kvichak and Togiak Bays.
3.1.2 Substrate Characteristics
Sediment Analysis. The results of the sediment analyses are presented
in Table 3.1-1, which reports the percent sand, gravel and silt, geometric
mean diameter and sorting index for the 60 samples analyzed.
Most samples in the study area were predominated by sand, as shown in
Figure 3.1-13. At least one sample from each of the study areas except
Bristol Bay contained >10 percent gravel. Six of the seven KB samples
contained from 42 to 91 percent gravel, four of the fifteen TB samples
contained 41 to 62 percent gravel, and two of the nine IL samples
contained 30 to 54 percent gravel. By contrast, samples from the
Bristol Bay subarea contained little or no gravel, but had the greatest
amounts of silt, ranging from 0 to 33 percent. Station TB130, near Cape
Newenham, had 16 percent silt; none of the remaining stations sampled
had >5 percent silt. The geometric mean diameter for the BB samples was
lowest and the sorting index was highest. Samples containing gravel
were poorly sorted by comparison to the deeper, Bristol Bay samples.
The percentage gravel information is presented as contours (by orders of
magnitude) in Figure 3.1-14. This figure shows the apparent large-scale
distribution of gravel deposits in the study area.
Observational data concerning substrate material in trynet and rock/
dredge samples are presented in Figure 3.1-15. The distribution of
gravel or larger sized substrates from these observations agrees fairly
well with the distribution obtained from sediment sample data. The
Shipek sampler used to obtain sediments works poorly in larger grained
sediments, thus, shell and cobble substrates were not adequately
sampled. Observations indicated that substrates with significant
amounts of whole and broken shell debris were found at 50 m and deeper
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