PROGRESS IN BIOLOGICAL INQUIRIES, 1939 37 
lation of the fish food present with the food organisms consumed by 
the coho young from the time of hatching until their seaward mi- 
gration. This procedure, together with a “study of the influence of 
varying environmental conditions on the growth and time of seaward 
migration of the young, was aimed to give insight into the fresh- 
water mortality of the species. 
In order to locate suitabie key streams for these studies a general 
survey was made of the impor tant streams in the region. Five tribu- 
{aries were selected, each of which differed from the other in its 
source, distance from salt water, size, shaded areas, type of bottom, 
mean temperature, and, to some extent, in chemical composition. The 
selection of streams with varying environmental conditions was made 
in order to include the important fresh-water habitats frequented 
by coho salmon. 
A new type of sampler for streams, designed by Dr. Davidson and 
Mr. Kelez, is being used to determine qualitatively and quantitatively 
the bottom fauna and its variations. The new sampler is more 
efficient than net types, since it can be used in a variety of locations 
such as in sand, mud, vegetation, and gravel, and it takes an exact 
quantitative sample. An example of its efficiency is shown by the 
numbers of Chironomidae larvae that are consistently taken in the 
sampler, whereas these forms are usually, if not entirely, missed by 
other samplers due to the small size of the larvae and their depth 
in the gravel. Collections of chemical and physical data on the 
streams, bottom samples, and coho fry or fingerlings are taken each 
month. 
Hatchery experiments.—In cooperation with the Division of Fish 
Culture, a series of experiments are being conducted to test the re- 
actions of coho fry and fingerlings to various concentrations of sea 
water. The relative tolerance to salt water, and rapidity of adap- 
tation to higher concentrations exhibited by fish of varying age, 
would have a definite bearing on the time of release of hachery- 
reared fish. ‘The experiments were begun at the Quileene Hatchery 
in November. 
SURVEY OF ALASKAN LAKES 
Dr. Wilding was detailed to southeastern Alaska from July to 
October to study certain lakes and streams in cooperation with the 
U. S. Forest Service. The purpose of the survey was to determine 
the physical, chemical, and biological characteristics of the waters in 
one to formulate a trout- stocking and conservation program. Ten 
lakes in Southeastern Alaska, and Wonder Lake in McKinley Park, 
were surveyed. The analysis of the lakes included: Temperature 
series, dissolved oxygen and free carbon dioxide, pH, carbonates, bot- 
tom fauna, fish, and plankton samples. The amount and suitability 
of spawning area was determined and fish- and egg-planting sites 
were located. In certain general characteristics the lakes were quite 
similar, especially in regar d to their oligotrophic nature, high oxygen 
content, low bacterial. decomposition and carbon- dioxide content, 
slightly acid reaction, absence of vegetation, and scarcity of bottom 
organisms. The plankton population was extremely variable from 
lake to lake, and in general there were numerous organisms of a few 
species. A detailed report of the investigation has been prepared 
and a stocking policy recommended. 
