PROGRESS IN BIOLOGICAL INQUIRIES, 1939 49 
1931 year-class represented 54 percent of the catch in 1937, 48 per- 
cent In 1938, and 32 percent for we ace responding period in 1939. 
Here, again, the spawnings of 1932, , and 1934 were almost total 
failures, their combined ea o the catch during the fall of 
1939 being less than 5 percent. With the disappeara: nee of this 
dominant 1931 year-class, and because the succeeding 3 brood-years 
failed to contribute any measurable portion to the Ce catch, a further 
decline in the population level may be anticipated in this area for 
the 1940 season. 
Southeastern Alaska—The season’s catch for Southeastern Alaska 
in 1939 was 160,000 barrels, compared to a 10-year average of 434,000 
barrels in the area, and was the lowest catch recorded since the 
inception of the intensive reduction fishery 15 years ago. The suc- 
cess or failure of this fishery has been dependent almost wholly on 
the abundance and availability of the stock of herring frequenting 
the Cape Ommaney area. The continuing decline in the abundance 
of this population, as reflected in a declining catch per unit of gear, 
led to a closure of the Cape Ommaney area during the 1939 season, 
although nearly 72,000 barrels of the total catch were taken’ from 
this same population outside of the closed area. 
Samples of the size and age composition of the catch in this area 
were again collected. In the Cape Ommaney region, as in Kodiak 
and Prince William Sound, the 1931 year-class dominated the catch 
for several years, but by 1938, due to the more intensive fishing in 
this area, had practically disappeared. Here, too, the spawnings 
of 1932, 1933, and 1934 were virtual failures. The decline in this 
fishery to a dangerously low level must be attributed, in no small 
measure, to this failure of the young to survive. 
A survey of the spawning grounds oe Sitka, which is the source 
of the Cape Ommaney stock of her ring, was made during the spring 
of 1939. For the second consecutive year the run in this important, 
area was exceedingly light, giving further proof that the decline 
in abundance as measured by the “eatch per unit of gear is valid. 
Incidental to this survey, an effort was made to determine the effect 
of Sal elas and dessication on the survival of eggs spawned in 
the intertidal zone. The clusters of eggs could not. be separated 
for microscopic examination without hardening them in a fixative. 
When the eggs were hardened they became opaque which precluded 
‘a determination of viability. Thus the attempt resulted only in the 
development of a technique for hardening, separating, and clearing 
egos which will make possible future accurate estimates of mortality 
due to temperature and dessication. 
PACIFIC PILCHARD INVESTIGATIONS 
O. H. Serre, in charge 
The problem of the pilchard investigation is to determine the 
amount that can be safely harvested annually without jeopardizing 
future yields* This determination is complicated by the existence 
of natural fluctuations in abundance, which are caused by differences 
from year to year in the numbers of fish surviving the early stages 
of life. There are also variations in availability, so that the com- 
4 Progress in Biological Inquiries, 1938, pp. 43-47. 
