Fishery bulletin of the Fish and Wildlife Service - NOAA

FLUCTUATIONS IN ABUNDANCE OF RED SALMON,
ONCORHYNCHUS NERKA (WALBAUM), OF
THE KARLUK RIVER, ALASKA
By JOSEPH T. BABNABT, A. M., Aquatic Biologist, Division of Fishery Biology, Fish and Wildlife
Service
Page
Introduction — 237
Statistical history of the fishery 238
Age at maturity .241
Spawning populations 247
Total populations 252
Returns from known spawning populations
255
Chemical analyses of lake and stream
waters 260
Change in age composition of the population
267
Seaward migrations 272
Sex ratios of adult fish 275
Marking experiments 277
Marking of Karluk River red
salmon 281
CONTENTS
INTRODUCTION
Page
Marking experiments—Continued.
Recovery of marked fish
Experiments in 1926
Experiments in 1927 and 1928
Experiments in 1929
Experiments in 1930 ._
Experiments in 1931
Experiments in 1932.
Experiments in 1933
Discussion of marking experiments
Mortality in fresh water
Summary and conclusions
Literature cited
281
282
283
283
284
286
287
289
290
291
292
294
One of the major problems of the Federal Government on the Pacific coast is the
conservation of the Alaska salmon resources which yield more than 280 million pounds
of salmon to the commercial fisheries each year. In order to conserve these resources,
so as to provide for an optimum yield each season, it has been found necessary
to impose certain regulations on the fishing industry. These regulations aim
primarily to provide an adequate escapement of the salmon to the streams eachseason
so that they may reproduce and maintain the supply. 1 i
Knowledge of fluctuations in the abundance of salmon populations provided
the basis upon which the regulations were formulated. Since the commercial catch
records gave insufficient and frequently unreliable information on the abundance
of salmon, picket weirs were established in a number of important salmon rivers
through which the fish were counted on their upstream migration to the spawning
grounds. The count of the number of salmon migrating into a river, together with
the record of the commercial catch in the locality of the river, furnished information
' Pacific salmon spend the early part of life In fresh water, the time spent there depending on the species and locality. They
then migrate to the ocean and after a varying period of time return to fresh water to spawn. Fishery Bulletin 39. Approved for
publication May 6,1940.
237