Fishery bulletin of the Fish and Wildlife Service - NOAA

130 FISHERY BULLETIN OF THE FISH AND WILDLIFE SEBVICE
landings per week derived from the figures given in table 17, and shown in the
following statement:
Total number of deliveries per week in Zones 1 and Z during June and July
Week ending Dcltoeriei
June 11- _ 1, 551
June 18 2, 008
June 25 : 2, 229
July 2 2,283
July 9 2, 692
July 16 2, 647
July 23 2,424
July 30 3,013
It is shown by the preceding statement that the number of deliveries practically
doubles during the months of June and July—an increase in fishing effort that could
readily account for the fact that the count at Bonneville Dam does not increase,
although there is better than a fourfold increase in the number of fish taken in the
fishery in Zones 1 and 2.
In this connection it has been of interest to determine something of the relationship
that exists between the abundance of fish as measured by the average poundage
per delivery and the number of deliveries. The number of deliveries may be taken as
a fair measure of the number of men fishing. We have, therefore, taken these two
series of values from table 17 and calculated the coefficient of correlation. This
proved to be +0.75. The interpretation is quite clear that the abundance of fish, as
shown by the size of the individual catches, is an important factor in determining the
number of fishermen that will fish.
INTENSITY OF FISHING IN GENERAL
The runs of chinook salmon considerably outweigh in importance and value the
runs of all other species in the Columbia River fishery combined. Of the entire run
the part that enters the river during spring and early summer, April to July inclusive,
is the most valuable on account of the fine quality of the fish. This part of the run,
perhaps more than any other, has been adversely affected by the reduction of spawning
areas and localities suitable for the rearing of the young fish that has attended the
utilization of the water resources in the headwaters, especially for power and irrigation.
Since the salmon industry began on the Columbia River the chinook has been
the mainstay of the fishery and the most relentless exploitation has fallen upon the
spring run.
It has been shown above that the present intensity of fishing is such that, in
1938, over 80 percent of the spring run and between 60 and 70 percent of the main
fall run of chinook salmon were taken in the commercial fishery. In this connection
it is pertinent to recall that in the regulation of the Alaska salmon fisheries the Federal
Government, acting through the Fish and Wildlife Service, has adopted the principle
that the escapement should be not less than 50 percent of the entire'run. There are
sound theoretical grounds for thinking that the maximum sustained yield of the salmon
fisheries can be maintained with an escapement of this order of magnitude, and
the practical results obtained with the Alaska fisheries support this view. It seems