312 
BULLETIN OF THE BUREAU OF FISHERIES 
catch which was pickled in 1928 was composed largely of herring spawned in 1922 
and 1923. Just because fluctuations in the catch may be caused by dominant year 
classes, it must not be supposed that a very small spawning population is sufficient for 
the continuance of a prosperous fishery, and the very fact that the success of spawning 
does vary, makes it more necessary that there be an adequate number of spawners to 
tide over periods of unfavorable years. Since the offspring of the abundant adult 
population of the early years were so greatly reduced in numbers before reaching 
maturity, one can not hope that the small numbers of offspring that will survive to 
maturity from the spawning of as scarce an adult population as that of 1928 will be 
sufficient to maintain the fishery. 
Cook Inlet . — The analysis of the data in Cook Inlet is complicated by the fact 
that two methods of fishing are employed, gill netting and purse seining. Previous 
to 1923 only gill nets were employed, but in that year one purse seine was used, and 
/9/8 /920 /922 /924 /Q26 /Q2<5 
Figure 51. — Th catch of raw herring per fathom of gill net in certain years from 1918 to 1928, 
inclusive, in Kachemak Bay, Cook Iniet 
since then gill netting has played a minor role. Unfortunately, no records are avail- 
able which show the total number of gill nets fished each year, or which separate the 
gill-net and purse-seine catches of those operators employing both methods of fish- 
ing. However, there are seven years in which we have accurate records of the fath- 
oms of gill net used by a portion of the operators. For these years the following 
data are available: 
Year 
Fathoms 
of gill 
net 
Pounds of 
raw herring 
caught 
Year 
Fathoms 
of gill 
net 
Pounds of 
raw herring 
caught 
1918 
1,782 
500 
450 
550 
2, 313, 339 
1, 293, 968 
1, 097, 355 
1, 810, 496 
1926- 
4,370 
6,110 
3,075 
1, 051, 932 
982, 181 
795, 115 
1921 
1927 
1923.. 
1928_ 
1924 
From this has been calculated the average catch per fathom of gill net. (Fig. 
51.) Among the earlier years there are records of the gear only in 1918. If this one 
year is representative of the abundance of that period, there was a considerable rise 
up to the level of 1921 to 1924. If this rise is valid it can be accounted for by a change 
<o 
1 
§ 
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