estimate made during years that had heavy rains of 
long duration during the peaks of spawning runs is not 
comparable with an estimate made during normal 
water levels: 
Streams where intertidal spawning pre- 
dominates may present difficult observation conditions 
at high tide. Spawning salmon in the intertidal zone 
behave differently when the spawning areas are flooded 
by the high tide. 
Aerial observations vary with the different 
types of aircraft used. Observations made from small 
light planes capable of following winding stream 
courses are more reliable than those made from larger 
planes which must fly at considerable height above the 
stream and generally at greater speeds. 
Physical Observations 
Observations of the characteristics of each 
stream by different observers have been recorded with 
varying degrees of accuracy. Many details of stream 
descriptions are dependent upon the individual observer's 
ability and knowledge. 
Many stream dimensions are merely estimates. 
Instruments for measurements were usually not available 
to observers and pacing and estimating were used. 
Most basic stream distances have been taken 
from aerial photographs and are relatively accurate. 
However, some errors may have occurred where refer- 
ence points were difficult to identify. Drainage 
estimates were based on compensating polar planimeter 
measurements of valley areas, but occasionally drain-~ 
age divides were difficult to distinguish and the areas 
given are only approximate. 
EXPLANATION OF CATALOG FORMAT 
Further descriptions of the data such as estimates 
of timing, temperature ranges, spawning facilities, 
etc. , are included under these specific headings in the 
explanation of the catalog format that follows: 
Stream Designations 
Statistical area number. --The number used by 
the Bureau of Commercial Fisheries to designate the 
statistical area is given in the upper left side of the 
heading. 
Stream name. --This appears in the center 
of the first line of the heading. Recorded names or 
common local names are used when available. Other- 
wise unnamed streams of importance are given descrip- 
tive names corresponding to location or other dis- 
tinguishing features. Some streams have identical 
names; they are retained without change due to local 
usage. Many minor streams have no names; hence 
they are identified only by number. 
Stream number. --This number appears on 
the right side of the first line of the heading. The 
letter preceding the number designates the adminis- 
trative district in Southeastern Alaska: e.g. , 'K" 
for Ketchikan. Continuity of stream numbers along 
a shoreline is followed where practical. Due to the 
numerous islands, breaks in the sequence have been 
necessary. Non-hyphenated numbers designate 
major or important streams. A catalog number 
which includes a hyphenated number designates a 
tributary to the stream of the same number. A cata- 
log number combining numbers and letters desig- 
nates a minor stream, either adjacent to or between 
major streams numbered in sequence. For example, 
stream number 17A is a minor stream adjacent to 
major stream number 17. 
Latitude and longitude, --This appears on 
the second line, left side, of the heading. Location 
of streams is given by the use of "'N" for north lat- 
itude, and "W" for west longitude, stated in degrees 
(°), minutes and tenths of minutes; minute symbol 
(') is omitted. Location of the high tide point on 
the stream is given for positive identification. 
Previous number. --This appears on the 
second line, right side, of the heading. Stream 
number or numbers used in the past by Fish and Wild- 
life Service are given for positive identification of 
old stream records. 
Geographic location. --This appears on 
the third line of the heading. Each stream location 
is described by the administrative district, major 
channel, bay or inlet, arm or cove, and location 
within the smallest division given by direction 
(from true north) and distance (nautical miles). 
Major species. ~-Included are those species 
of salmon which comprise the bulk of spawning in 
the stream. Where more than one dominates, both 
(or more) are included. 
Other species. --This indicates other known 
species of salmon and trout using the stream. 
Escapement timing. --The timing is based 
on systematic stream survey records, which include 
a number of years of surveys with visits before, near, 
and after the peaks of abundance. Extensive stream 
temperature studies were conducted in conjunction 
with most of these surveys. The earliest runs of 
salmon occur along the colder mainland streams. 
The latest runs are in the outer channel and coastal 
areas where stream levels are dependent uponrainfall. 
