616 
BULLETIN OF THE BUREAU OF FISHERIES 
The catch of cohos has increased tremendously during the period under con- 
sideration as shown in figure 44. There was no great difference in the northern and 
southern parts of the strait up to about 1920, but since then the catches in the south 
have averaged approximately twice those in the north — just the reverse of the con- 
ditions with respect to the red salmon. 
The catches of king salmon have never been large and, so far as our records go, 
have been very irregular. It is interesting to note that there have been periods in 
which years characterized by very good catches of kings alternated with years in 
which the catch was very small, and that in every case the large catches were made 
on even years. This is suggestive of some sort of an association between the king 
and pink salmon fishery (since the pinks are exclusively 2-year fish) but no such 
association can at present be pointed out. 
Figure 44. — Catch of coho salmon in the Clarence Strait district, 1888 to 1927. 
The Clarence Strait district as a whole surpasses all other districts in south- 
eastern Alaska in the total production of salmon. The only indication of weakness in 
its fisheries is shown in the catches in 1927, a year of poor runs generally in the south- 
eastern area. The fishing effort in 1927 was certainly not lower than in previous 
years, as 183 traps and 42 seines were operated as compared with 118 traps and 116 
seines in 1925, yet the total catch in this district was only a little over 1% millions as 
compared with nearly 12 milllions in 1925. The catches of kings, cohos, and reds 
were not materially lower but those of the other species were far below their normal 
levels. Just why there should have been poor runs of pinks and chums in the same 
year is problematical, but there can be no doubt that the fact is of biological signifi- 
cance. It is well known, of course, that the pinks are exclusively 2-year fish while 
the chums vary mainly from 3 to 5 years in age at maturity. Poor runs of both 
species coming in the same year may have been merely coincidence; but if not it 
