PROGRESS IN BIOLOGICAL INQUIRIES, 1939 9 
ings was accompanied not by a price increase, but by a slight de- 
crease; the average being 2.8 cents per pound in 1938 and 2.6 cents per 
pound m 1939. 
Conditions in the mackerel fishery have not been encouraging to 
owners of New England vessels which annually account for more than 
one-half of the total mackerel production. The last 5 years have 
witnessed a steady decline in the number of purse seiners entering the 
mackerel fleet; in 1935, there were 99, but only 49 in 1939. Most of 
the 50 vessels lost to the mackerel fishery have taken up groundfish: 
dragging. Dependable profits to fishermen in a well-established rose- 
fish fishery, especially, have offered relief from the uncertainties of 
the mackerel supply and discouraging financial returns. Such uncer-- 
tainties are not new to the mackerel fishery. Violent fluctuations in. 
the catch from one year to the next have bothered the trade and the: 
fishermen for more than a century. 
The mackerel investigation begun in 1926 had for its purpose the 
discovery of causes for the great differences in annual yield, with a 
view toward turning its findings to economic advantage. Several 
lines of investigation were inaugurated for solution of the problems. 
These were: (1) The collection of catch records, to provide a means of 
comparing past with present production of mackerel. (2) The de- 
termination of a measure of abundance not affected by changes in the 
size of the fleet or the amount of gear fished. (3) The study of such 
salient features of mackerel biology as might have a bearing upon the 
problem; geographical distribution, spawning habits, rate of growth, 
life span, migrations, ete. (4) A study of conditions in the sea to 
determine what environmental factors influenced appreciably the 
biological features mentioned above. 
Catch records assembled from many sources revealed an 80 to 100 
million-pound production level, roughly speaking, from 1804 to 1885. 
This was the “hey-dey” of the fishery, when annual production oc- 
casionally exceeded 100,000,000 pounds. The last such peak, in 1884, 
was followed by a drop to about 25,000,000 pounds in 1886. Since 
that time mackerel production has averaged approximately 30,000,000 
pounds a year. The last good year was 1935, when total Atlantie 
coast landings approximated 80,000,000 pounds. In 1937, the total 
production was about 25,000,000 pounds. 
Mackerel first appear off Virginia in the spring, and are found 
progressively northward to the Gulf of St. Lawrence as summer 
advances. The offshore fishery rarely extends more than 100 miles 
from shore, while the activity of the fleet is confined largely to a strip 
of water averaging less than 50 miles from the coast. With the 
approach of cold weather, mackerel apparently leave the Gulf of St. 
Lawrence and head southward. Until 3 years ago the fishery had 
ceased off southern New England by the end of December. During 
the past 3 years, however, a few purse seiners have continued opera- 
tions into January. 
Observations have demonstrated that spawning in the southern 
part of the range takes place between April and August. Due to 
rapid summer growth, mackerel attain minimum marketable size their 
first fall: about 8 or 9 inches in length. Asa rule, the maximum size 
attained is about 22 inches in length and about 4 pounds in weight, 
during a life span of approximately 12 years. 
