92 
BULLETIN OF THE BUREAU OF FISHERIES. 
lake is surrounded by comparatively low, flat shores. Beyond the city of Sand- 
point the lake is shallow and empties into the Pend d’Oreille River. 
Clarks Fork and Pack River with the numerous mountain streams bring a 
tremendous amount of water into the lake, especially during the “spring rise.” 
Although there is no dam at the outlet the average change of level during a season 
is 5.2 m. (17 feet), and a maximum of 8.2 m. (27 feet) has been recorded. The 
depths of the various parts of the lake are given on the map (fig. 14). The section 
between Hope and Bay View is so deep that it seldom freezes, and boats run between 
these points all winter. 
The lake is noted for its char or “Dolly Varden” trout ( Salvelinus bairdii), 
which reach a large size and offer excellent sport. The cutthroat trout ( Salmo 
clarkii ) is also abundant. The lake trout ( Cristivomer namaycush) was planted in 
this lake, but no catches have been reported, although this lake appears to be ideal 
for this species. 
Due to the great depth of this lake and the suddenness with which a storm could 
come up it was impossible to anchor a small boat or to work very long at a time. 
With respect to depth no lake studied during this survey offers more of interest 
than does Lake Pend Oreille. The largest amount of plankton was above the 
thermocline, or above the 10-15 m. stratum, as 59 per cent of the Crustacea and 
66 per cent of the nauplii were found there. (See Table 12, p. 130, and fig. 16.) 
A few nauplii, however, were found as deep as 200 m. Both Diaptomus ashlandi 
and Cyclops bicuspidatus were found in a catch at the bottom of the lake (360 m.) . 
The maximum numbers of Diaptomus and DapTmia hyalina per cubic meter of 
water were found in the 0-10 m. stratum. D. hyalina was not found below 50 m. 
Notholca longispina was the only rotifer noted in the limnetic catches. 
Very little phytoplankton was found in any of the catches. Oscillatoria was 
the predominant alga and was confined to the upper 20 m. of the lake, 11 per cent 
of the strands being found in the 0-10 m. stratum of the lake and 81 per cent in the 
10-20 m. stratum. Between 200 and 300 m. a few strands of Fragilaria and 
Tabellaria were found. Even the larger forms of aquatic plants were compara- 
tively scarce. Most of the shore of the lake was of such a nature that it would be 
almost impossible for them to get a foothold. 
PRIEST LAKE, IDAHO. 
This beautiful body of clear, soft water lies 32 km. northeast of Sand Point, 
Idaho. It is usually reached by a 40 km. (25 mile) drive from Priest River, Idaho. 
It is completely surrounded by virgin forest, being a part of the Kaniksa National 
Forest. Its greatest length is 38.5 km. (24 miles), which with its irregular shape 
(see map, fig. 17) gives it an extended shore fine. 
Although mountains surround the lake, they are some distance from it, and 
most of the shore rises gradually, offering numerous beautiful camping sites. This, 
combined with the clean sand beaches and good trout fishing, makes the lake very 
popular as a s umm er resort. 
